task 3 technical assessment of major structures...preliminary planning study new railway line...

Preliminary Planning Study

New Railway Line Dresden - Prague

Task 3 Technical Assessment of Major Structures

15. December 2015

Preliminary Planning Study New Railway Line Dresden-Prague Task 3 Technical Assessment of Major Structures

Content 3. Technological assessment of main structures ...........................................................4

3.1 Route of the line........................................................................................................4

3.1.1 Location (surface conditions, objects) .......................................................................4

3.1.2 Route planning parameters (route, gradients, overlaps) ............................................5

3.2 Tunnel structures ....................................................................................................12

3.2.1 Ground conditions (layers, ground water situation) .................................................12

3.2.2 Occurrence of fault zones .......................................................................................19

3.2.3 Construction method (shotcrete method / TBM method) .........................................24

3.2.4 Technological parameters for the construction process ..........................................36

3.2.5 Management of the volumes of excavated and blasted materials ...........................38

3.2.6 Tunnel structures ....................................................................................................50

3.2.7 Loading gauge and design of cross-section and emergency stopping point ............60

3.2.8 Design principles for tunnel lining, drainage and sealing and for structural fire protection ................................................................................................................68

3.2.9 Type and positioning of the safety and rescue systems ..........................................76

3.2.10 Logistics concept ....................................................................................................78

3.2.11 Analysis of geotechnical and construction method risks ..........................................80

3.2.12 Assessment of the feasibility of the chosen tunnel solution .....................................81

3.3 Major bridges and viaducts .....................................................................................87

3.3.1 Required structures ................................................................................................87

3.3.2 Assessment criteria ................................................................................................87

3.3.3 Bridge Structures ....................................................................................................89

3.3.3.3 Seidewitz viaduct ....................................................................................................96

3.3.4 Construction costs ................................................................................................ 100

3.3.5 Next steps in the planning process ....................................................................... 100


Task 3 Technological assessment of main structures

3. Introduction

The actual railway routing of the line is based on the line routing in the preferred alternative 1.1 from the 2012 study (Project TEN 22, „Study of line/route alternatives for joint cross-border planning“), which is to be optimized as a result of further studies on the sensitivity of the area, the basic geological and hydrogeological data and the planning on the Czech side.

The main connecting nodes Dresden (Heidenau) Line No. 6240 and at the D/CZ border after the E 55 (A 17) motorway – Ústí nad Labem (Prague) were derived from the 2012 study on the new railway line.

The area being examined for its spatial and environmental resistances starts on the German side south of Dresden in the Heidenau district at the Station Heidenau Süd on the existing railway line Dresden – Pirna no. 6240.

It continues in a south-easterly direction past Pirna via the Pirna-Zehista district (Seidewitz Tal) towards Dohma, and then in a large curve via the mountain ridge Lohmgrundrücken towards the southwest bypassing the health resorts of Berggieshübel and Bad Gottleuba, towards Breitenau also bypassing the Gottleuba dam and reaching the Czech border.

The route crosses the E 55 (A 17) motorway on the Czech side west of the Spicak Mountain (723 m + NN) and leads south towards the town of Chlumec. The area being studied ends on the Czech side where the new line is integrated into the existing SZDC network north-east of Chabarovice and into the new railway station in Ústí nad Labem.

Because of the geographical situations in the valleys of the Elbe and the Seidewitz River and the Ore Mountains and in view of the maximum permissible longitudinal gradient, the route mostly runs via tunnels and a major bridge structure.


3.1 Route of the line

3.1.1 Location (surface conditions, objects)

The final result of the feasibility study submitted in 2012 showed three different variants for the railway layout (No. 1.1, 1.2, and 2).

The variant 1.2 did not correspond to the planning target for the operation of trains with a mass of up to 1600 t to be run without restriction because of the longitudinal slope of 20‰ in some sections. The variant 1.2 was therefore disclosed for the next planning step.

The variant 1.1 complies with the restriction of a longitudinal slope of 12.5 ‰, therefore this variant was the preferred solution in 2012.

In this study a route alternative was developed from the preferred variant 1.1.

This optimized variant 2015 does not cross the Bahretal and the community of Gersdorf which possesses excessively high spatial resistance for these two settlements and also avoids expected impact for the FFH-conservation area DE-5049-304 Bahrebachtal and the bird protection area DE- 5048-451 Osterzgebirgstäler like the initially preferred variant 1.1.

Conflict Analysis

In the course of a conflict analysis (tasks 2.1 and 2.2), the following environmental aspects were studied within a defined planning corridor along the previously defined preferred variant 1.1 (2012 study):

• settlement areas

• spatial development plans

• projects planned by third parties

• nature and the environment

• geophysics (mining, fault zones).

The land use conflicts that arose were categorized and structured with regard to the railway route and the conflicts which are significant for decisions on the route were identified. The individual conflicts were looked at in more detail and the route was optimized as far as possi-ble with regard to these constraints.

Route Optimizations

Furthermore a number of route optimizations for the prevention and control of the anticipated effects on the environment have been made:

1. At the connection to the existing line in Heidenau the tunnel beginning has been shift-ed in order to reduce the expected impact on a FFH-conservation area and on settlements areas like Heidenau industrial park or an old underground cavity called „Pechkeller“.


2. The planned railway viaduct in the Seidewitz valley was placed closer to the planned Pirna road bypass (DEGES project) to minimize the interference with the existing settlement structure in the urban district “Zehista” (bundeling effect).

3. In the area of “Lohmgrundrücken” the required open cut section at the beginning of the border tunnel has been shortened by extending the tunnel, reducing significantly the permanent effect on the groundwater.

The final optimized route 2015 is around 800 m shorter than the preferred alternative 1.1 from 2012

3.1.2 Route planning parameters (route, gradients, overlaps)

According to the project specifications, the route of the new railway line is to be designed for high-speed passenger traffic with v max = 200 / 230 km/h and goods traffic with v max = 120 km/h. For this parameters DB Netz AG regulations specify that the new railway line shall be assigned to a route standard classification called M 230.

The operational speed on this section will be between 160 km/h and 230 km/h.

The distance between the centres of the track is therefore 4.50 m (4.00 m for TSI routes).

For overtaking of trains the distance between the track passing stations should be between 8 km and 20 km according to DB regulations. Sections of the track for overtaking should be 750 m long for goods trains.

Crossover switches should be at intervals of 8 km (distance from station) and 20 km according to DB regulations.

Blocks for signalling purposes should be between 1.5 km and 4.0 km long in accordance with the design calculations.

Speeds of entry into/exit from sets of point switches should be between 80 and 100 km/h.

In crossovers, speeds should be between 80 and 100 km/h.

According to railway regulation TSI-INF-2014-1299, the maximum permissible longitudinal gradient for mixed traffic lines is 12.5 ‰.

The gauge profile GC specified by EBO/TSI must be complied with.

According to DB regulations, the route is classified as load category D4 (axle load 22.5 tons, line load 8 t/m) + SSW (heavy load waggon).

On tracks used for overtaking, hot wheel and axle detection devices must be installed.


A further requirement for the route resulted from the agreements with DB Netz AG, which believes that the existing line 6240 Dresden-Pirna needs to be retained in the future for goods traffic. At least one existing track towards Pirna should remain. As an alternative, a planning study of a two-track continuation towards Pirna is to be carried out.

Figure 1: Sketch map of the new Dresden – Prague railway line


3.1.2.1 Exit point at Heidenau (near Dresden)

Similarly to the preferred alternative, the route of the new railway line begins at the exit point south of Heidenau at km 49.671 on DB line No. 6240 with the installation of a crossover with 4 sets of point switches (W 101 to W 104, type 60-1200-1:18,5 fb). The maximum speed on line No. 6240 is 160 km/h and the crossovers (W 101 to W 104) are designed for a speed of 100 km/h.

After the crossovers, at km 49.680 on the existing line, the existing route is diverted after the crossing of the Geschwister-Scholl-Strasse Bridge at km 49.450. The existing line 6240 to-wards Pirna (1- or 2-track) separates from the future Dresden-Prague railway line. After the line No. 6240 branches off, the New Line (NL) starts to ramp up parallel to the line No. 6239 (city railway) at a gradient of 12 ‰ with a U-shaped ramped trough structure around 660 m long.

At NL-km 0.514 on the new line (km 48.580 on line No. 6240), the crossover of the new line over line 6240 starts with a flyover in the form of a reinforced concrete frame structure around 280 m long with lateral openings in the walls. The bridge structure that crosses exist-ing buildings (Heidenau industrial park) and the B 172 road starts at NL-km 0.800 on the new line.

The start of the bridge structure consists of a two-track superstructure over 4 bridge spans until the line widens and continues after 6 further single-track superstructure spans directly into a cutting and from NL-km 1.350 (1.390) into a tunnel structure with two tubes.

Due to the different track layouts, the total length of the bridge structure is 473 m for the Dresden-Prague track and 517 m for the Prague-Dresden track.

In view of the existing building situation (industrial park between B 172 road and line No. 6240 Dresden-Pirna), the exit area in Heidenau must be re-routed from preferred alternative 1.1 due to new buildings next to the existing line (constraints). The start of the tunnel has also been relocated because of its proximity in preferred alternative 1.1 to a special FFH ar-ea of conservation and an underground cavity („Pechkeller“); it is now located further to the east outside these areas.

Heidenau – Großsedlitz Tunnel

This tunnel with twin tubes (at a distance of ca. 29 m) starts at NL km 1.350 and ends at around NL-km 3.300. Due to the topography of the area, the tunnel structure is interrupted by a ca. 120 m long trough structure from NL-km 2.150 to 2.270.

After passing under the K8272 road (Großsedlitz – Pirna) and the B 172a main road, the tunnel ends at the south portal and the line enters into a trough structure up to NL-km 3.370 which is followed by an embankment structure (length ca. 800 m) up to NL-km 3.800. At the end of the tunnel, the distance between the tracks on the new line is reduced again to 4.50 m between track centres.


Seidewitz Viaduct

After this, from NL-km 3.800 to km 4.850, there is a two-track bridge with a distance of 4.50 m between track centres (length ca. 1.050 m, maximum height ca. 37 m) which crosses the Seidewitz river valley and the Zehista district west of the planned Pirna road bypass B172n.

In view of the existing planning for the Pirna road bypass B172n, the route was moved closer to this planned road in order to minimize the impact on existing buildings. This change in the route alignment also made it possible to bypass the Schützengrund industrial waste site south of Zehista.

Due to the tighter routing and a smaller radius of the track centreline, the maximum speed on the viaduct is restricted to a maximum of 180 km/h.

Embankment and overtaking station at Goes

From NL-km 4.840, this is followed by a two-track section around 2.000 m long up to the minor K8753 road (level with Goes) at km 6,800. Up to this station, the new route is similar to the preferred 2012 route with a distance of 4.50 m between track centres and a gradient of 12.0 ‰.

For technical and cost reasons, crossovers and overtaking tracks should not be planned in tunnels (cf. Brenner Base Tunnel). Therefore two overtaking tracks with a usable length of 750 m were planned on the embankment in the Goes section with a maximum gradient of 2.5 ‰. The connecting point switches for the overtaking tracks (W 003 to W 006) are of type 60-1200-1:18,5 fb and are designed for speed of ve = 100 km/h when branching off. In front of and behind the connecting points there are crossovers (W 001/002 and W 005/006) which are also designed for a speed of ve = 100 km/h.

DB regulations require an overtaking station at a maximum distance of 20 km (lower limit of route utilization) as shown in the diagram below and a maximum longitudinal gradient on the line of 2.5 ‰:

Figure 2: Diagram for overtaking station


Lohmgrundrücken and the start of the cross border tunnel (variant A)

Up to now, the planning for the preferred route 1.1 in 2012 assumed that a cutting up to 28 m deep and ca. 2.2 km long with shallow slopes would be constructed at the mountain ridge Lohmgrundrücken. These slopes are requiring intensive structural retaining constructions.

Up to now, after the Goes section, the distance between the tracks on the route widens in a cutting around 2.700 m long parallel to the state road S 173 up to where the tunnel begins at NL-km 9.155 with two single-track tunnel tubes (around 200 m north of the road S 170, the Ottendorf-Friedrichswalde bypass).

The longitudinal gradient of the route in the cutting up to the tunnel portal is 12 ‰ and from the tunnel portal onwards it is 4 ‰; the route climbs to the highest point after around 9.200 m at NL-km 18.347 (level with Börnersdorf), after which it slopes downwards towards the Czech Republic at a gradient of ca. 3 ‰ over a length of around 15.130 m. On the German side, the maximum tunnel coverage is ca. 310 m and on the Czech side it is ca. 550 m.

According to evaluations of the geological and hydrogeological data in collaboration with the saxonian authority of geology (LfULG), this deep cutting would have had a permanent signifi-cant impact on ground water levels in a zone that is sensitive from a geotechnical point of view (layers of weathered rock to a depth of 20 m).

After evaluation of the hydrogeological data, ground water level is believed to be around 8 to 9 m below the ground surface. The tops of the rails would be up to 20 m below natural ground water level. A deep cutting would cause major interference with the ground water conditions over the entire Lohmgrundrücken.

Alternative: Extension of the tunnel at Lohmgrundrücken (variant B)

Because of the operational necessity to arrange a bypassing station at Goes the level of the track would be 10 m below the preferred variant 1.1 the depth of the open cut would increase even more in the variant B.

With an elongation of the cross border tunnel it will be possible, to implement the bypassing station just before the northern tunnel portal and to reduce the impact on the groundwater aquiver significantly.

The length of the open cut can be reduced by about 1.660 m and furthermore initially the very large amounts of excavated material (see the following table).


Comparison of the Excavation Volume

Variant A Variant B

Length of cutting in final state 2.340 m 680 m Length during open construction (temp. cutting) 160 m 460 m

Total length of temp. cutg 2.500 m 1.140 m

Excavation volume of permanent cut with trough 1.443.783 m³ 152.641 m³ (Exc. volume of permanent cut without trough 2.300.000 m³)

Excavation volume of tunnel during open construction (temporarily) 312.479 m³ 1.147.461 m³

Excavation volume for cutting (total) 1.756.595 m³ 1.300.101 m³

Filling volume for tunnel in open construction 219.339 m³ 968.091 m³

Difference (Excavation - Filling) 1.537.256 m³ 332.010 m³

Total Balance

Filling volume for embankment structures 986.792 m³ 698.355 m³

Excess Volume / Open Volume 550.464 m³ -366.345 m³ Total length of border tunnel 24.645 m 26.531 m Excavation volume using mining techniques 4.100.550 m³ 4.373.460 m³

Difference (Excavation - Filling) 4.651.014 m³ 4.007.115 m³

Significantly smaller excavation volumes are produced in the Lohmgrundrücken cutting with the variant B (lower gradient) and the filling volume for the embankment structure is reduced; during tunnel excavation, the excavation volume increases by ca. 273.000 m³. This results in a reduction of ca. 645.000 m³ in the volume of excavated material to be dumped or recycled and avoids major permanent interference with ground water conditions. Therfore the solution of variant A must be ruled out for environmental reasons.

Adjustments to tunnel planning

These conditions lead to a changed planning solution (Alternative B) in which the border tun-nel lies deeper and can be preceded by an overtaking station with a maximum longitudinal track gradient of 2.5 ‰.


The gradients in the area of the route from the overtaking tracks near Goes up to the highest point of the border tunnel have been changed. The tunnel now starts at NL-km 7,200 and the highest point of the tunnel has moved to NL-km 19296 so that a minimum longitudinal gradient of 4 ‰ in the tunnel can also be achieved on the Czech side. The length of the open cut area in front of the tunnel was reduced to 655 m.

Cross Border Tunnel, Börnersdorf section

The optimized route bypasses the geological structure near Börnersdorf around 400 m further to the west than in the previous planning. In this area, it is also possible to provide intermediate access to the tunnel crest via a ca. 230 m deep shaft. This would be useful from a construction logistics point of view due to the junction with the A 17 motorway. The vertical shaft can be used later for ventilation and as a means of access for fire and emergency ser-vices.

Further optimization of the tunnel route with regard to the Usti nad Labem node and/or the tunnel portal on the Czech side is dependent on the results of the planning process in the Czech Republic.

The current route must be assessed in the context of the geological and hydrogeological conditions which must be investigated in more detail in the future. Adjustments to the routing of the tunnel tubes may be necessary.

3.1.2.2 Location of the necessary track-switching equipment

Track-switching equipment that is necessary for operational reasons should no longer be located in tunnels according to a UN study (Recommendations of the multidisciplinary group of experts on Safety in Tunnels (Rail) 2002) and the current planning for the Brenner Base Tunnel.

In terms of construction and fire protection, the effort involved in installing track-switching equipment in a tunnel with two tubes is considerable, whereas the operational advantages are minor.

In this project, track-switching equipment is planned on the German side immediately in front of the tunnel (overtaking station at Goes) and on the Czech side at the next station in Ústí nad labem. The distance between these stations is 34.90 km.


3.2 Tunnel structures

3.2.1 Ground conditions (layers, ground water situation)

3.2.1.1 General information

The geological information in the study of alternatives in 2012 indicates the tunnels on the new line must mostly be excavated through a mountainous region containing the following formations:

Cretaceous

Elbtalschiefergebirge

Crystalline

For the initial phase of tunnel planning the LfULG (Landesamt für Umwelt, Landwirtschaft und Geologie) provided the following information:

Notes from a meeting with presentation in Freiberg on 19.01.2015 on geology/hydro-geology for the new Dresden-Prague railway line (Appendix)

On 27.03.2015, the planners were also given a geological overview section (preliminary profile) based on LfULG’s geological maps. LfULG recommends that until a concrete model for the area of the route km 0.0 to km 4.0 is available, two alternatives should be considered.

o Gradients (tunnels/cutting) in accordance with the cross-section in the Cretaceous (sandstone/marl) and crystalline layers (granodiorite)

o Gradients (tunnels/cutting km 1-1.5) in deviation from the cross-section in the Qua-ternary layers (thicknesses up to 20 m).

3.2.1.2 Geology

According to the initial preliminary geological profiles, the geological situation described be-low can be assumed for both tunnels. It is expected that from north to south, the following rock layers will have to be cut through during tunnelling:

Heidenau–Großsedlitz Tunnel

Granodiorite

Metamorphic rock, crystalline – Proterozoic (Dohna granodiorite)

Granodiorite is a transitional form between diorite and granite (coarsely grained plutonic rock). Note: in the transition area, the solid rock may have a deep weathered zone.


Sandstone

Sedimentary rock, Cretaceous formation

Sandstone mostly consists of grains of quartz held together by bonding agents. The sand-stone found here is from the Cretaceous period (cf. Elbe sandstone mountains, Elbsand-steingebirge).

Base tunnel, Erzgebirgstunnel

Sandstone

See above

Greywacke

Sedimentary rock, Elbtalschiefergebirge geological region, Paleozoic

Greywacke consists of grains of quartz, feldspar, chlorite and mica flakes together with frag-ments of siliceous and argillaceous shale, chert and quartzite.

Alkaline vulcanite

Volcanic rock, Elbtalschiefergebirge

Vulcanites are effusive rocks (here alkaline magma). Vulcanite-sedimentary successions can occur here with inclusions of carbonates and siliceous rock. Also diabasic tuff, known as greenstone (diabas = basalt with a medium-grained structure).

Phyllite

Metamorphic rock, Elbtalschiefergebirge

Phyllite is a finely flaking crystalline shale mostly consisting of quartz and sericite which re-sults from argillaceous shale through metamorphosis. The phyllites that occur here contain quartzite.

Granite

Magmatic plutonic rock, crystalline

Granite is a coarsely grained plutonic rock consisting of feldspar, quartz and mica.


Gneis

Metamorphic rock, crystalline (here transformed and/or in general)

Gneis is a metamorphic rock consisting mainly of feldspar, quartz and mica. Gneis can origi-nate from magmatic rock such as granite (orthogneis) and also from sedimentary rock, e.g. argillaceous shale (paragneis).

Vulcanite

Effusive rock, Tertiary

In the area where the Erzgebirge mountains slope down steeply on the southern side, vulcanites (basalt) from the Tertiary formation occur.

Clays - shales

Tertiary

Transition to loose rock in the area of the southern portal

Sands

Tertiary

Loose rock in the area of the southern portal


As an overview of the types of rock that occur along the route, Figure 3 below shows the key to the preliminary geological profile produced by LfULG.

Figure 3: Key to longitudinal geological section


3.2.1.3 Geological situation in the area of the tunnel structures

The geological situation is described in the tables in the appendices with reference to the kilometre points in the tunnels. This results in the following overview of the layers that have to be cut through:

Heidenau–Großsedlitz Tunnel – Part 1

western km 1.350 to km 1.540 190 m open construction

eastern km 1.380 to km 1.560 180 m open construction

Granodiorite (11) in the areas of the gradients and below Sandstone (4) above in the tunnelling area

western km 1.540 to km 2.140 600 m mining construction

eastern km 1.560 to km 2.150 590 m mining construction

Granodiorite (11) in the area of the gradients and below Sandstone (4) above The sandstone / granodiorite line falls below the gradients from about km 1.925.



Sandstone (4) entire tunnel excavation

Heidenau–Großsedlitz Tunnel – Part 2




western km 2.420 to km 3.130 710 m mining construction

eastern km 2.400 to km 3.140 740 m mining construction

Sandstone (4) entire tunnel excavation with mining methods





Ore Mountain Base Tunnel Alternative A (long cutting)

The information below refers to Alternative A (long cutting). Due to the minor differences in the geological subsections for the positions of the gradients in Alternative B (short cutting), the data will not be repeated here.

km 9.155 to km 9.315 160 m open construction


km 9.315 to km 9.780 465 m mining construction

Sandstone (4) entire tunnel excavation using mining methods

km9.780 to km 9.850 70 m mining construction

Faults (8) Weesensteiner fault / Donnerberg fault


Sandstein (4) Greywacke (7)

km 10.000 to km 11.365 1.365 m mining construction

Greywacke (7)


Alkaline vulcanite „greenstone series“ (6)


Phyllite (5)


Faults (8), granite (13), mid-Saxony fault


Gneis transformed (10)


Gneis in general (9)




Gneis, transformed (10)


Vulcanite, basalt (3c)

















Faults (8)


Sandstone (4)


Vulkanite, basalt (3c) and sandstone (4)


Sandstone (4)


Clays and shales (3a)


Sands (3b)


Clays and shales (3a)

km 33.500 to km 33.800 300 m open construction


3.2.2 Occurrence of fault zones

3.2.2.1 Geophysical aspects of the geological fault zones in the Börnersdorf area

Information on the Börnersdorf geological structure is available in the publications by TU Freiberg in 2013 [35] and by LfULG [36]. In accordance with this information, the relevant fault zone is localized and delimited.

The chosen routing of the planned line bypasses the geological fault zone on the west at a sufficient distance for both tunnel tubes, so that no negative influences on the tunnel tubes are to be expected.

Figure 4: Section of location plan, Börnersdorf fault zone

3.2.2.2 Further investigation of cavities in karst or old mining tunnels

The digital cavity map provided by the Upper Mining Authority of Saxony was evaluated as part of the study. The diagrams below show the cavities which lie in the vicinity of the planned route as sections from location plans. Due to the distances between the cavities in the vicinity and the planned route, no further geophysical studies are planned in connection with the planning of the route.


Figure 5: Section of location plan, cavity Bergkeller Pechhütte

Figure 6: Section of location plan, NL-km 12.6 – 13.4, eastern


Figure 7: Section of location plan, NL-km 12.6 – 13.4, western Burgk. Fundgrube, Richard Grube

3.2.2.3 Further fault zones

Further geological fault zones such as the Weesensteiner, Donnerberg, Winterleite and mid-Saxony fault zones are shown in the longitudinal geological overview section as fault zones (8).

Further information about their type and extent and their possible effects on the tunnel construction technology is not available at the present time. After the information has be-come more concrete, the effects of the fault zones must be taken into consideration when selecting suitable tunnelling technology.

Our current opinion is that they will have no effect on the routing of the line or the positions of the gradients.

3.2.2.4 Cottaer Tunnel

Near km 8,6 on the new Dresden-Prague railway line, the route crosses the disused Cottaer Tunnel. This tunnel is located on line 6604 which was closed down in 1999. The tracks on the line were dismantled in 2002. The portals of the tunnel were closed. The diagrams below give some information on the Cottaer Tunnel.


Figure 8: Section of location plan, new Dresden-Prague line – Cottaer Tunnel

Figure 9: Drawings of the Cottaer Tunnel [19]


Figure 10: Cottaer Tunnel – northwestern portal [19]

Figure 11: Cottaer Tunnel – southeastern portal [19]


3.2.3 Construction method (shotcrete method / TBM method)

There are two main methods for constructing tunnels; the conventional shotcrete method (NATM) [cyclical tunnelling] and mechanized tunnelling using a TBM [continuous tunnelling]. The main principles of both methods are described below. Tunnels can also be constructed using the open construction method, but this method will not be discussed in further detail here.

3.2.3.1 Shotcrete method (NATM)

Cyclical tunnelling

o Excavation / blasting / support / removal of excavated material

o Excavation over entire tunnel cross-section / possibly in partial cross-sections (calotte, bench, floor)

o Length of work sections depending on geological conditions

o Usually 2-3 work sections per day depending on prevailing conditions (geolo-gy, requirements of environment e.g. noise nuisance for nearby residents, ex-perience / pace of driving team [detonation, support, removal of excavated material] etc.)

Figure 12: Starting wall of tunnel, mining method, securing with pipe roof, divided calotte [photo: K+K]


Figure 13: Preliminary cut, shotcrete support with grouted anchors [photo: K+K]

Figure 14: Tunnelling by blasting – boring the blast holes [photo: K+K]


3.2.3.2 Mechanized tunnelling

Continuous method

o Tunnelling, securing / support of rock using TBM, installation of tubbing, removal of excavated material etc. using TBM or other technology

o TBM is a high cost factor but cost-effective for longer tunnels

Figure 15: Breakthrough of both TBMs, Katzenbergtunnel [Photo: Company Herrenknecht [8]]

3.2.3.3 Criteria for the selection of tunnelling methods

Under certain conditions, both methods have advantages and disadvantages in comparison with other methods. The evaluation of experiences in different tunnel projects show some tendencies for the advantages of the TBM method, but these tendencies cannot necessarily be transferred in general to other projects. Table 1 below shows some main criteria for the selection of tunnelling methods.


Table 1: Criteria for selecting tunnelling methods

Criteria for the selection of tunnelling methods for the “Erzgebirgstunnel” cross border tunnel

Selection criterion

Cyclical tunnel-ling (NATM)

Continuous tunnelling (TBM)

Structure: Tunnel length (driving length) Cross-section – area to be excavated Quality of structure Subsoil: Geological conditions Geotechnical conditions Hydrogeological conditions Construction procedure: Flexibility in the event of geological “challenges” Cross-sections deviating from standard cross-section Tunnelling in difficult soil conditions, especially ground water Accuracy of excavation cross-section profile Single-shell final cross-section Extent of required area for construction site equipment Advance rate Climate in tunnel during tunnelling – ventilation/temperature Occupational safety during tunnelling Deadlines and costs: Availability of tunnelling equipment Lead time up to start of tunnelling Construction time Construction costs Cost-effectiveness of faster tunnelling via intermediate access Environmental, safety and regional aspects: Effects of noise and vibrations Settlement Re-use of excavated material / dumping Added value in the region Strategy and innovation: Promotion of innovation / competition between methods Benefits for other projects

Key

unfavourable neutral favourable cannot be adequately assessed at present


Explanation of the main selection criteria

Tunnel length (driving length)

For short tunnels, the cyclical method (NATM) is usually superior to the continuous method (TBM) for reasons of cost-effectiveness. The break-even point lies at a driving length of around 2 km.

Figure 16: Cost comparison TBM – blasting method [7]

Cross-section – area to be excavated

The area to be excavated (cross-section) is similar for both methods and will be around 80 – 90 m² for the planned single-track tunnel tubes.

Quality of the structure

The quality of the resulting tunnel structure in its final state is considered to be equally good for both alternatives.

Subsoil

On the basis of the currently available geotechnical information it is not possible to adequately assess the two tunnelling methods with respect to the geological, geotechnical and hydrological conditions. Further investigative measures are needed for an assessment. Here we refer to Chapter 3.2.1 „Ground conditions (layers, ground water situation)“ with respect to the geotechnical and hydrological investigations that are still to be carried out.


Flexibility in the event of geological challenges

If very changeable geological/hydrogeological/geotechnical conditions occur, it is always possible to react with a variety of remedial measures when using the cyclical method. From a technical and construction contract point of view, the method to describe the variation of the driving class is a good option. In contrast, when using mechanized tunnelling, the methods are limited by the nature of the procedure and/or the very high costs involved.

Construction of cross-sections which deviate from the standard cross-section

With continuous tunnelling, the area being excavated is a circular cross-section due to the nature of the method. When a tunnel structure is excavated mechanically, variations in the profile such as widened cross-sections, crossovers, underground operations rooms etc. must be constructed conventionally using the NATM, for process-related reasons. Depending on the geology, almost any tunnel cross-section can be constructed using the NATM.

Tunnelling in difficult subsoils, in particular in ground water

When using the NATM, tunnelling in difficult subsoils - in particular in ground water - requires time-consuming and expensive additional measures. In comparison, it is more efficient to cut through these using the mechanized method.

Accuracy of the profile of the cross-section being excavated

With mechanized tunnelling, an accurate profile can usually be achieved with a minimum damage to the surrounding rock and only a minor excavation over profile. In contrast, under adverse conditions, the conventional NATM leads to a higher excavation over profile of around 10% of the cross-section being excavated. Also, blasting inevitably leads to a certain amount of rock disturbance and loosening of the rock due to the nature of this method.

Single-shell construction cross-section

The final finishing of tunnel structures built using the mechanized method is usually single-shell. In contrast, the shotcrete shell (external shell of the tunnel) created in the NATM usual-ly serves as a temporary support for the excavation cross-section. The interior tunnel shell is constructed afterwards.

Apart from these process-related conditions, the decision on single- or two-shell finishing depends on other important parameters. This decision is determined by the geological and hydrological conditions and by the impermeability, structural stability and fire protection re-quirements that apply to the tunnel.


Area required for construction site equipment

When using mechanized tunnelling, the area required for construction site equipment for very long tunnels in comparable projects is of the order of ca. 80.000 to 150.000 m². This is be-cause smooth operation of a mechanized tunnel boring process requires a perfectly orga-nized production and logistics centre where the associated infrastructure is available on site. Cost-effective production of the tubbing, for instance, is normally only possible on site be-cause of high transport costs and the requirements for fast availability of large numbers of components.

In comparison, the area required for construction site equipment for conventional tunnelling (NATM) amounts to ca. 10 - 25 % of the figures mentioned above.

Advance rates

Evaluations of comparable projects with very long tunnel structures and the publication „NATM and TBM – comparison with regard to construction operation“ [10] show an average advance rate for mechanized tunnelling of 15 - 20 m/d. Peak performances of over 100% and above the average advance rate can be achieved. However, the risk of temporary inter-ruptions to tunnelling work due to difficult rock conditions is greater than when using the cy-clical method.

With the cyclical method, experience shows that the advance speed is 5 – 8 m/d. Advance rates averaging 10 m/d are possible in stable rock with mid-range cross-sections and over longer sections with consistent geological conditions. However, depending on the geological conditions and the securing measures they demand and the possible need to subdivide the excavation cross-section, advance rates may be much lower. Factors such as noise pollution due to blasting near residential areas can also lead to a reduction in the advance rate if they mean that blasting at night is not permitted.

Tunnel climate during construction - ventilation / temperature

As tunnelling length increases, ventilation may become difficult. When using the NATM, ex-plosive gases, exhaust fumes from loading and transport machines and the dust produced by the dry-mix shotcreting process all affect air quality. Due to its nature, mechanized tunnelling preserves a better air quality in the tunnel. A further criterion is the temperature in the tunnel interior. This may lead to a need for cooling the air.


Occupational safety during tunnelling

With respect to occupational safety and the associated safety concepts, TBM has ad-vantages over NATM. In particular, shield machines together with a full tubbing lining provide a very high level of safety for tunnelling personnel in the event of geology-related accidents. Tunnelling personnel are always protected by the TBM shield skin and/or the completed tub-bing shell. In contrast, using NATM means a significantly higher residual risk for tunnelling personnel in the immediate working area [9].

Availability of tunnelling equipment

The standard machines required for conventional NATM tunnelling are usually immediately available from the relevant tunnel construction companies or can be provided at very short notice. In contrast, obtaining a TBM is very cost-intensive and time-consuming, especially in the case of a completely new TBM. With very long tunnels, the cost factor becomes less rel-evant as the tunnelling length increases. The time saving resulting from using NATM is 8 - 12 months, whereby the lower limit applies to fully overhauled used TBM equipment.

In order to reduce the deployment time for a TBM, a check should be carried out to see if a tunnel structure with a similar cross-section and tubbing segment structure has already been realized. An overview of completed tunnel projects together with the TBMs that were used can be found in [11].

Lead time up to the start of tunnelling

The entire lead time for the deployment of a new TBM consists of ca. 2-3 months of engi-neering work, 10-12 months of production, 1-2 months for transport and ca. 3 months of in-stallation and initial operation [9]. The total lead time is therefore ca. 20 months. In the case of using fully overhauled TBMs, the “production time” can be reduced from ca. 12 months to ca. 8 months.

The impact of a reduction in the lead time for mechanized tunnelling on the total construction time depends on the other preparatory measures that are needed. Where extensive advance construction activities are necessary before tunnelling can start, the lead time becomes less relevant or completely irrelevant.


Construction time

Construction times for tunnel structures are determined by many individual factors. Based on the advance rates described above for the cyclical and continuous methods, and looking at the methods individually, the result is that a tunnel that is bored mechanically can be com-pleted 2-3 times faster than when using the conventional method. However, when multiple sections are bored at the same time using the conventional method, which in comparison with TBM can be achieved with significantly lower costs for the provision of tunnelling equip-ment, calculations of construction times give very different results. In the case of mechanized tunnelling, the necessary lead time before tunnelling can begin must also be taken into con-sideration.

Furthermore, mechanized tunnelling with single-shell finishing of the tunnel cross-section using tubbing means that the final state is already reached after the first pass through the tunnel, whereas in the conventional method, an inner shell made of in-situ concrete is usually constructed after the tunnelling process.

The considerations described here only represent a small number of factors influencing con-struction times. For this reason, we refer to the representation of the outline time schedule in Chapter 5.1 “Outline time schedule“.

Construction costs

A representation of the construction costs can be found in Chapter 5.2 “Outline cost plan-ning“.

Cost-effectiveness of using intermediate access for faster tunnelling

Due to the wide availability of standard equipment for conventional NATM tunnelling and the low costs (in comparison with mechanized tunnelling) for acquiring / supplying the tunnelling equipment, the cyclical method means that the process can be speeded up in a cost-effective way by using intermediate access points. However, the cost-effectiveness of con-structing the main tunnel depends on the additional costs involved in creating an intermedi-ate access point.

Effects of noise and vibrations

As a result of the blasting which is necessary when using the conventional method to tunnel through rock, noise and vibration are to be expected. The significance of this criterion when assessing the two tunnelling methods increases depending on land use in the area of the construction project (residential, mixed or industrial areas).


Settlement

Settlement is influenced by the tunnelling method itself and by the existing geological condi-tions. Due to the geotechnical investigations which are still to be carried out, it is not yet pos-sible to adequately assess the two tunnelling methods with regard to settlement.

Use/dumping of excavated material

Material excavated by mechanized tunnelling is characterized by a high proportion of fine material with a flat, stem-like grain shape. This makes it more difficult to process as aggre-gate in concrete production and leads to higher cement consumption. These factors can be partially compensated using an optimized concrete formulation.

Because of the different advance rates and the resulting differences in the amounts of exca-vated material produced, the required temporary storage or recycling facilities must be de-signed with different dimensions.

Using NATM, the volume of excavated material that has to be recycled is lower due to the cross-section being ca. 6 % smaller.

Using NATM, shotcrete residues in the excavated material usually lead to increased values in the pH and conductivity parameters [10].

Depending on the prevailing conditions, where a fluid supported shield or an earth pressure shield is required to support the excavation cross-section, conditioning agents may be nec-essary. If the chemical content of conditioning agents in the excavated material is low, it can be used for open filling of classes Z0 to Z2 in accordance with the relevant regulations (LAGA M20). If it contains a high proportion of chemicals, it must be deposited at an appro-priate landfill site or a hazardous waste landfill site (classes Z3 to Z5) [1].

Added value in the region

Mechanized tunnelling together with the required infrastructure (production and logistics cen-tres, tubbing production, accommodation, catering etc.) can lead to added value in the region in the form of workplaces, tax revenue etc. due to the associated auxiliary construction ser-vices and the number of workers required.

Strategy and innovations

The promotion of tunnelling methods results in increased innovations and competition be-tween different tunnelling methods is encouraged. This benefits both the tunnelling methods themselves and subsequent projects.

Here, the length of the border tunnel represents a further development in the construction of railway tunnels in Germany.


Selection of tunnelling methods

Decision-making on the tunnelling methods is a dynamic process, which, during the planning phases, demands step-by-step decisions and further requirements resulting from these. These must constantly become more and more detailed and further optimized as the depth of the planning process increases.

Figure 17: Flow chart – dynamic decision-making process [1]

Figure 18 shows an example of the geotechnical planning procedure, from determining the geotechnically relevant parameters right through to deciding on the driving classes and fore-casting the homogeneous areas for the individual driving classes.


Figure 18: Diagram showing the geotechnical planning procedure [2]


3.2.4 Technological parameters for the construction process

The technological parameters for the tunnelling process mainly result from the planning con-ditions in the expert reports on subsoil and tunnel construction, as well as from the technical tunnel construction concept which results from these.

For mechanized tunnelling, technical machine planning must be part of the construction pro-cess. The technical machine parameters must be determined conceptually in the bid phase and in detail during the construction phase on the basis of the results of the geotechnical planning process and the conditions in the tender documents.

The rock conditions are not completely known since the advance explorations were carried out at specific points, so the geotechnical model and the construction and technical machine parameters must be verified during the construction process and adjusted if necessary to the rock conditions actually found during tunnelling.

Figure 19 shows an example of planning for mechanized tunnelling in the construction phase.


Figure 19: Diagram showing construction planning process [2]


3.2.5 Management of the volumes of excavated and blasted materials

As part of the further planning process for the planned infrastructure project „New Dresden-Prague railway line“, a materials management concept must be developed. This concept must point out solutions for the management of excavated and blasted materials that are technically feasible, environmentally and spatially acceptable and also cost-effective. The management of the excavated and blasted materials is a task that is limited in duration and limited to the construction phases of the overall project, but its impact will continue long after completion of the project due to the high quantities of the materials involved and in view of the raw materials market and possible re-cultivation.

The critical conditions for materials management can be divided into 5 groups as shown in Figure 20 below. Each group represents different parameters that can affect materials man-agement.

Conditions affecting management of excavated and blasted materials

Geology Technology Law Material requirements

Geotechnology

Geochemistry

Petrography

Tunnelling method

Processing of materials

Construction site organization

Concrete technology

Alkali-aggregate reaction (AAR)

Environment

Waste disposal law

Procurement law

Ownership of material

Project requirements

External requirements

Conformity with regional raw materials market

Ecological balance sheet for project

Emissions during processing of materials

Burden on existing traffic routesGermany, Saxony /

Czech Republic Germany, Saxony / Czech Republic

Dumping and recultivation

Figure 20: Conditions affecting management of excavated and blasted materials

3.2.5.1 Effects of the tunnelling method

The choice of tunnelling method is a major factor that determines the characteristics of the material produced by the tunnelling process. Material excavated mechanically contains a higher proportion of fine material with a flat, stem-like grain shape. This makes it more diffi-cult to process as aggregate in concrete production and leads to higher cement consump-tion. These factors can be partially compensated using an optimized concrete formulation.


Using NATM, the volume of excavated material that has to be recycled is lower due to the cross-section being ca. 6 % smaller.

Using NATM, shotcrete residues in the excavated material usually lead to increased values in the pH-value and the conductivity parameters [10].

Depending on the prevailing conditions, where a fluid supported shield or an earth pressure shield is required to support the excavation cross-section, conditioning agents may be necessary which have an impact on the environment. If the chemical content of the excavat-ed material is low, it can be used for open filling of classes Z0 to Z2 in accordance with the relevant regulations (LAGA M20). If it contains a high proportion of chemicals, it must be de-posited at an appropriate landfill site or a hazardous waste landfill site (classes Z3 to Z5) [1].

3.2.5.2 Quantities of excavated materials and the areas required for construction equipment

Because of the different advance rates and the resulting differences in the amounts of exca-vated material produced, the required temporary storage or recycling facilities must be de-signed with appropriate dimensions.

When using mechanized tunnelling, the area required for construction site equipment for very long tunnels in comparable projects is of the order of about 80.000 to 150.000 m². This is because smooth operation of a mechanized tunnel boring process requires a perfectly orga-nized production facility and logistics centre with the associated infrastructure on site. Cost-effective production of the tubbing, for instance, is normally only possible on site because of high transport costs and the requirements for fast availability of large numbers of compo-nents.

In comparison, the area required for construction site equipment for conventional boring (NATM) amounts to ca. 10 - 25 % of the figures mentioned above.

3.2.5.3 Alkali-aggregate reaction (AAR)

With respect to the use of the excavated material as aggregate for concrete production for the structures in the project itself, we refer to the explanations on materials management and concrete technology at the Lötschberg Base Tunnel [13]. Geological information gained from the Lötschberg Base Tunnel shows that the behaviour of certain types of rock such as gneis, siliceous limestone and granodiorite is unfavourable with respect to the alkali-aggregate reaction(AAR) [13]. As part of the exploratory measures still to be carried out, these types of rock should be studied more closely detail with regard to their use as concrete aggregate.


As part of the further planning processes and also during construction, these results should be assessed from a concrete technology point of view and a concept for the use of these materials should be produced and updated. The most important points are e.g. [13]:

Systematic investigation of AAR reactivity for the materials intended to be used as concrete aggregate

Suggestion for the selection of appropriate concrete systems

Preliminary investigations to find AAR-resistant formulations

Development of reference concrete formulations that are optimal in terms of quality requirements and costs.

3.2.5.4 Overview of the quantities of excavated and blasted materials over the entire project

The tables below show rough estimates of the quantities of excavated and blasted materials that will be produced during the „New Dresden-Prague railway line“ infrastructure project.

For the „Lohmgrundrücken“ cutting at the northern portal of the border tunnel, Alternatives A (long cutting) and B (short cutting) as described in Chapter 3.2.6.3 are considered. Further-more, the overview of the quantities for Alternatives A and B also includes a division of the quantities of blasted materials from the border tunnel into the part that will be produced in the Federal Republic of Germany (state of Saxony) and the part that will be produced in the Czech Republic.

Table 2: Overview of quantities – Heidenau-Großsedlitz Tunnel

Heidenau-Großsedlitz TunnelTunnel section using mining methods – Part I Sandstone (4) 43.200 m³Granodiorit (11) 52.800 m³Excavation volume 96.000 m³

Tunnel section using mining methods – Part II Sandstone (4) 113.600 m³Granodiorit (11) 0 m³Excavation volume 113.600 m³

Heidenau-Großsedlitz Tunnel – overview of total volume Sandstone (4) 156.800 m³Granodiorit (11) 52.800 m³Excavation volume 209.600 m³

Overview of quantities"Heidenau-Großsedlitz Tunnel"


Table 3: Overview of quantities – border tunnel Variant A (long cutting at the „Lohmgrundrücken“)

Border tunnel – overview of quantities in D [Saxony] / CZTunnel section using mining method - D [Saxony] Clays and Shales (3a) 0 m³Sands (3b) 0 m³Vulkanite: Basalt (3c) 0 m³Sandstone (4) 91.800 m³Phyllit (5) 127.500 m³Alkaline Vulcanite "Greenstone Series" (6) 354.450 m³Greywacke (7) 244.800 m³Faults (8) 11.900 m³Gneiss in general (9) 969.000 m³Gneiss, transformed (10) 382.500 m³Weesensteiner Greywacke (12) 0 m³Faults (8) - Granite (13) 42.500 m³Excavation volume - Tunnel section D [Saxony] 2.224.450 m³

Tunnel section using mining method - CZClays and Shales (3a) 35.200 m³Sands (3b) 14.400 m³Vulkanite: Basalt (3c) 21.210 m³Sandstone (4) 91.600 m³Phyllit (5) 0 m³Alkaline Vulcanite "Greenstone Series" (6) 0 m³Greywacke (7) 0 m³Faults (8) 31.200 m³Gneiss in general (9) 1.166.200 m³Gneiss, transformed (10) 516.290 m³Weesensteiner Greywacke (12) 0 m³Faults (8) - Granite (13) 0 m³Excavation volume - Tunnel section CZ 1.876.100 m³

border tunnel - overview of total volumeClays and Shales (3a) 35.200 m³Sands (3b) 14.400 m³Vulkanite: Basalt (3c) 21.210 m³Sandstone (4) 183.400 m³Phyllit (5) 127.500 m³Alkaline Vulcanite "Greenstone Series" (6) 354.450 m³Greywacke (7) 244.800 m³Faults (8) 43.100 m³Gneiss in general (9) 2.135.200 m³Gneiss, transformed (10) 898.790 m³Weesensteiner Greywacke (12) 0 m³Faults (8) - Granite (13) 42.500 m³Excavation volume 4.100.550 m³

Overview of quantitiesborder tunnel "Erzgebirgstunnel"

Alternative A (long „Lohmgrundrücken“ cutting)


Table 4: Overview of quantities – border tunnel Variant B (short cutting at the „Lohmgrundrücken“)

Border tunnel – overview of quantities in D [Saxony] / CZTunnel section using mining method - D [Saxony] Clays and Shales (3a) 0 m³Sands (3b) 0 m³Vulkanite: Basalt (3c) 0 m³Sandstone (4) 324.275 m³Phyllit (5) 127.500 m³Alkaline Vulcanite "Greenstone Series" (6) 357.850 m³Greywacke (7) 256.700 m³Faults (8) 6.800 m³Gneiss in general (9) 928.428 m³Gneiss, transformed (10) 382.500 m³Weesensteiner Greywacke (12) 57.375 m³Faults (8) - Granite (13) 42.500 m³Excavation volume - Tunnel section D [Saxony] 2.483.928 m³

Tunnel section using mining method - CZClays and Shales (3a) 10.400 m³Sands (3b) 7.360 m³Vulkanite: Basalt (3c) 19.210 m³Sandstone (4) 99.200 m³Phyllit (5) 0 m³Alkaline Vulcanite "Greenstone Series" (6) 0 m³Greywacke (7) 0 m³Faults (8) 32.000 m³Gneiss in general (9) 1.206.772 m³Gneiss, transformed (10) 514.590 m³Weesensteiner Greywacke (12) 0 m³Faults (8) - Granite (13) 0 m³Excavation volume - Tunnel section CZ 1.889.532 m³

border tunnel - overview of total volumeClays and Shales (3a) 10.400 m³Sands (3b) 7.360 m³Vulkanite: Basalt (3c) 19.210 m³Sandstone (4) 423.475 m³Phyllit (5) 127.500 m³Alkaline Vulcanite "Greenstone Series" (6) 357.850 m³Greywacke (7) 256.700 m³Faults (8) 38.800 m³Gneiss in general (9) 2.135.200 m³Gneiss, transformed (10) 897.090 m³Weesensteiner Greywacke (12) 57.375 m³Faults (8) - Granite (13) 42.500 m³Excavation volume 4.373.460 m³

Overview of quantitiesborder tunnel "Erzgebirgstunnel"

Alternative B (short „Lohmgrundrücken“ cutting)


3.2.5.5 Suggestions for use of the material

The aim of materials management is to achieve maximum re-use of the excavated and blasted materials. There are six main ways of using the material; these are shown in Figure 21. Here, the area of “Dumping (contaminated material)” will, in all likelihood, represent the smallest proportion and in view of the aims of materials management, this should also be the case.

Management of excavatedand blasted material

Requirements for building materialswithin the project

External requirements for

building materials

Recultivation within the region

Recultivation outside the region Dumping

Dumping (contaminated

material)

Concrete aggregate Building materialfor embankments

Figure 21: Management of excavated and blasted materials

Possible options and dimensions for re-use of the materials for re-cultivation / material stor-age in the Free State of Saxony are currently being investigated.


Use of material in recultivation / material deposition

As an option for the use of excess material from the tunnel construction project in recultiva-tion / material deposition, landscape modeling on the Kohlberg and Galgenberg hills was discussed in connection with this study as an LfULG idea.

The idea of landscape modeling should be investigated in more detail during the further planning process. As well as the positive effects of the landscape structure, unfavorable fac-tors that may exist should also be examined more closely.

Material deposition (transfer)

A further possibility for transferring the blasted/excavated materials is the filling of cavities in the surrounding surface mines. As part of this study, the following surface mines were named as possible sites for backfill masses:

Quarry at Oberottendorf (8609)

Quarry at Friedrichswalde-Ottendorf (8621)

Lime works at Borna (8613)

Gravel sand works at Pratzschwitz-Copitz (8628)

Quarry at Lauenstein (8305)

The quarry at Nenntmannsdorf and the floodwater retention dam at Niederseidewitz which is to be built by the state dam authority (Landestalsperrenverwaltung) can also be mentioned. Both of these could accommodate large quantities of excavated material if they were sched-uled to coincide with the construction of the new railway line.

The following information about the volumes of filling material [42] are rough approximations derived from the mine plans and/or operational planning and have been generously rounded down to be on the safe side.

It does not take into consideration

how the depletion and exploitation of the deposits (and thus the possible filling vol-umes) may develop in the future

whether the excavated material is actually suitable and permissible for filling in the relevant surface mines (e.g. also in the gravel lakes at Pratzschwitz-Copitz)

if a possibly necessary change of rehabilitation objectives (e.g. open water com-plete or partial filling) is desired and permissible.


Quarry at Oberottendorf (8609)

Mining company: Steinbruch Oberottendorf GmbH

Approval situation: Compulsory basic operations plan (RBP) (officially approved) valid until 31.12.2045

Volume to be filled: 1 million m3

Currently, the external waste heap adjacent to the quarry is gradually being filled into the quarry. The specified volume to be filled is available regardless of this.

Quarry at Friedrichswalde-Ottendorf (8621)

Mining company: ProStein GmbH & Co. KG


Volume to be filled: 0 m3

Filling during the construction period of the railway line will not be possible since the quarry will still be in operation after 2040 and deeper layers are to be accessed.

Lime works at Borna (8613)

Mining company: SK Sächsische Kalkwerke Borna GmbH

Approval situation: Non-compulsory basic operations plan (RBP) until 31.12.2016 ( 2036)

Volume to be filled: 0,8 million m3

The basic operations plan is currently being revised and an extension until 2036 is planned.

The lime quarry is to be partially filled; after a planned deepening of the quarry, at least 800.000 m3 of cavity space will be / are available.

Gravel sand mine at Pratzschwitz-Copitz (8628)

Mining company: Kieswerke Borsberg GmbH

Approval situation: Compulsory basic operations plan (RBP) until 28.11.2021

Volume to be filled: At least 3,5 million m3

At the moment it is planned that the areas of water should remain as open lakes for nature protection purposes.


Quarry at Lauenstein (8305)


Approval situation: Non-compulsory closure plan (ABP) until 31.12.2015 ( 2020)


An application for an extension of the closure plan to 2020 is being / has been submitted. The remaining volume to be filled refers to the partial filling that was originally planned.

Quarry at Nentmannsdorf (8614)




An application for an extension of the closure plan (ABP) to 2020 is being / has been submit-ted. The remaining volume to be filled refers to the partial filling that was originally planned.

The roughly estimated total volume to be filled amounts to ca. 5,9 million m³.

The figures below show the locations of the surface mines in the surrounding area.

Figure 22: New Dresden-Prague railway line – surface mines in the area, Part 1 [42]


Figure 23: New Dresden-Prague railway line – surface mines in the area, Part 2 [42]


Table 5 Overview of excavation quantities in Saxony (first approach) For the whole section in Saxony from Heidenau to the border

Sands and Silt 453.600 m³

Sandstone and Marl 2.088.775 m³

Phyllit 127.500 m³

Alkaline Vulcanite "Schalsteinserie" 357.850 m³

Greywacke 256.700 m³

Faults 6.800 m³

Gneise in general 928.430 m³

Gneise transformed 382.500 m³

Weesensteiner Greywacke 42.500 m³

Granodiorit 213.775 m³

Total Excavation Quantities 4.858.430 m³

General use as construction material 1.167.200 m³ (ca. 24 %)

Use as construction material at new railway line 1.990.800 m³ (ca. 41 %)

Recultivation / Material deposition 1.554.700 m³ (ca. 32 %)

Material to be dumped 145.750 m³ (ca. 3 %)


Responsibility for use of materials in the Free State of Saxony

The Upper Mining Authority of Saxony is responsible for all matters concerning the use of materials in the Free State of Saxony. All data collection and all permits required in this con-text are managed by Department 2 „Tagebau“ (surface mining), Unit 22 „Steine-Erden-Bergbau“ (quarrying and mining).

Figure 24 shows the organizational structure of the Upper Mining Authority of Saxony.

Figure 24: Organizational structure of the Upper Mining Authority of Saxony


3.2.6 Tunnel structures

The route sections in the areas of the planned Heidenau-Großsedlitz Tunnel and the cross border tunnel (Erzgebirgstunnel) have been analysed with respect to the currently available topographical data and to the geological, geotechnical and hydrogeological conditions. Re-garding the current exploration depth and the geotechnical and hydrological investigations which are still to be carried out but will be required during later planning stages, we refer to Chapter 3.2.1 “Subsoil situation (layers, ground water situation)” above.

3.2.6.1 Delimitation of open / mining method (NATM)

To determine the limits of the open and mining (NATM) methods, factors such as the geolog-ical, geotechnical and hydrogeological conditions, topography and cost-effectiveness aspects must be investigated and assessed.

Tunnels planned with concepts exclusively based on the open method can be realized at relatively low cost if the thickness of the tunnel roof cover is about 5 m to 7 m. Beyond this margin, comparatively higher costs must be expected due to the need for temporary pre-cuts and for coverage in the final state.

In contrast, when tunnels are constructed using mining methods, roof coverage of less than ca. 7 m to 8 m should be avoided if possible (or the length of such sections should be mini-mized) since shallow roof coverage can lead to special measures (e.g. driving class 7 with pipe roof). Conventional tunnel construction requires that an arched supporting ring can form in the rock surrounding the excavation cross-section. In stable soils (e.g. slope and weath-ered loams, weathered rocks at deeper bedrock levels), the depth of roof coverage should be at least 1.5 to 2 times the tunnel width B. In stable rock, in contrast, a roof coverage depth of Hü 1,0 B is sufficient. [12]

This means that the principles of the open construction method are partly opposed to those of the mining method. Taking a holistic view, tunnel sections constructed using the open method should be made as long as possible in order to minimize the special measures that result from a shallow depth of roof coverage when using the mining method.

Figure 255 below shows a comparison of the tunnel construction methods for different depths of roof coverage.


Figure 255 Delimitation of the open and mining (NATM) methods [12]


3.2.6.2 Heidenau-Großsedlitz Tunnel

Topography

In the most northern section of the Heidenau-Großsedlitz tunnel structure, the ground rises between NL-km 1.3 and 1.5 to a height of ca. +163.5 m above NHN-Level, referring to the right-hand track. Towards the east, the ground in this section slopes downwards. Between the right- and left-hand tracks the difference in ground surface height is up to ca. 2.5 m. Around NL-km 1.5+25.0 the ground falls to a minimum level of +148 m above NHN. It then rises again between NL-km 1.5+40 and 2.1+40 to a maximum of ca. +194 m above NHN.

Between NL-km 2.1+40 and 2.4+20, the ground level along the right-hand track varies in height from +154 to +172 m above NHN. Towards the east, the ground surface slopes downwards, in some places steeply. The difference in ground surface height between the right- and left-hand tracks in this section is up to ca. 6 m.

Further along, the ground rises again from NL-km 2.4+20 and reaches its maximum height of ca. +194 m above NHN ca. at NL-km 2.7+75. Further to the south, the ground surface falls again. In the area between NL-km 3.1+30 and 3.3+30, the maximum ground surface height is ca. +182 m above NHN.

Parts of the topography are shown in Figures 26, 27 and 28.

Figure 26: Part of longitudinal section - Heidenau-Großsedlitz Tunnel


Figure 27: Part1 of location plan, Heidenau-Großsedlitz Tunnel

Figure 28: Part 2 of location plan, Heidenau-Großsedlitz Tunnel

Figure 29: Part 3 of location plan, Heidenau-Großsedlitz Tunnel


Structures

Based on the topography described above and the currently available data on the geological, geotechnical and hydrogeological conditions, the structures shown in Table 5 below are sug-gested for the Heidenau-Großsedlitz Tunnel section. The table also includes a subdivision of the tunnel sections into open and mining methods.

For the transition from the tunnel pre-cut to the tunnel constructed using the open method, it is assumed that the depth of roof coverage is 7 m. For the approach and breakthrough areas using the mining method, a depth of roof coverage of Hü 1,5 x B (ca. 14 m) is assumed.

Table 6: Structural data

Structure

Single-track tunnel, open construction


Total length of tunnel

Cutting/trough or supporting structure


Single-track tunnel, mining method – Part II


Total length of tunnel

Single-track tunnel, mining method – Part I

Roof coverage / depth of cutting

from km to km length from km to km length

[m] [m] [m] [m] [m] [m] ca. [m]

1.350 1.540 190 1.380 1.560 180 7 - 14

2.140 2.150 10 2.150 2.160 10 14 - 7

800 780

2.150 2.270 120 2.160 2.380 220 15

2.270 2.420 150 2.380 2.400 20 7 - 14

2.420 3.130 710 2.400 3.140 740 14 - 32

3.130 3.300 170 3.140 3.330 190 14 - 7

1.030 950

590 14 - 421.540 2.140 600 1.560 2.150

1-track right(western)

1-track left (eastern)

Construction method

Open method

Open method

Open method

Cyclical method (NATM)

Open method

Cyclical method (NATM)


3.2.6.3 Cross Border Tunnel (Erzgebirgstunnel)

Topography

For the border tunnel (Erzgebirgstunnel), the topographically significant sections of the tunnel pre-cuts and the tunnel areas with relatively shallow depths of roof coverage are described below. No details are given of the major part of the border tunnel which is covered to a great depth, since in this area the topography has no relevance to the tunnel structure itself.

Lohmgrundrücken / Dohma (Free State of Saxony – D)

In the route section in front of the northern portal of the border tunnel, the gradients between NL-km 6.0 and km 7.0 of the embankment area continues into an open cut section. In this area, the ground surface is between +176 and +212 m above NHN. After that follows the cutting of the mountain ridge called „Lohmgrundrücken“ at NL-km 7.0

Two alternatives have been considered for this open cut. In Alternative A, there is a long cut in the final state. In contrast, the cut in Alternative B is significantly shorter. Because of the shortened open cut section, the cross border tunnel is extended by ca. 2 km. The cutting area continues up to NL-km 9.1 in Alternative A and to NL-km 7.2 in Alternative B. In this section of the route, the ground surface rises from ca. +212 m above NHN to +254 m and +231 m above NHN respectively.

Figure 30: Part of longitudinal section – border tunnel, northern portal area (D)


“Erzgebirgsabbruc”h (CZ)

In the route section between NL-km 32 and km 34, known as the “Erzgebirgsabbruch” (Ore Mountain ridge) area, which is the transition point to the open construction method and to the southern portal of the cross border tunnel, the ground surface falls from ca. +450 m above NHN to about +205 m above NHN.

Figure 31: Part of longitudinal section – border tunnel, southern portal area (CZ)


Structures

Based on the topography described above and the currently available data on the geological, geotechnical and hydrogeological conditions, the structures shown in the tables below are suggested for the border tunnel (Erzgebirgstunnel) section. The tables also contain a subdi-vision of the tunnel sections into open and mining methods.

Table covers the structures and sections in Alternative A (long cutting) and Table those in Alternative B (short cutting).

For the transition from the tunnel pre-cut to the tunnel constructed using the open method, it is assumed that the depth of roof coverage is 7 m. For the approach and breakthrough areas using the mining method, a depth of roof coverage of Hü 1,5 x B (ca. 14 m) is assumed.

Table 6: Structural data – Alternative A (long cutting)


Construction method

Structure from km to km length from km to km length

[m] [m] [m] [m] [m] [m] ca. [m]

Border tunnel “Erzgebirgstunnel”

Single-track tunnel, open construction 9.155 9.315 160 9.155 9.315 160 7 - 15 Open method

Single-track tunnel, mining method 9.315 22.400 13.085 9.315 22.400 13.085 5,5 - 335

Continuous method (TBM) /

[cyclical method (NATM)]

Tunnel section D [Saxony] 13.245 13.245

Border D [Saxony] / CZ

22.400 32.410 10.010 22.400 32.410 10.010 124 - 566



32.410 33.500 1.090 32.410 33.500 1.090 124 - 15Cyclical method

(NATM)


Tunnel section CZ 11.400 11.400

Total length of tunnel 24.645 24.645

km 22,4+0,000 km 22,4+0,000

Single-track tunnel, mining method

border tunnel "Erzgebirgstunnel" - Alternative A (long „Lohmgrundrücken“ cutting)




Table 7: Structural data – Alternative B (short cutting)

Lohmgrundrücken open cut section

For the open cut section at the „Lohmgrundrücken“ at the northern portal of the cross border tunnel, the previously described alternatives A (long cut) and B (short cut) were considered. The position of the initial tunnel excavation cross-section is determined by route-related technical parameters such as the longitudinal gradient in the tunnel and on the other hand by considerations of rock mechanics. From a tunnelling point of view, it is assumed that at the initial tunnel excavation cross-section will be a distance of ca. 25 m between the tunnel tubes axes.


Construction method

Structure from km to km length from km to km length

[m] [m] [m] [m] [m] [m] ca. [m]

Border tunnel “Erzgebirgstunnel”


Single-track tunnel, mining method 7.550 22.161 14.611 7.550 22.161 14.611 5,5 - 335



Tunnel section D [Saxony] 15.071 15.071

Border D [Saxony] / CZ

22.161 32.400 10.239 22.161 32.400 10.239 124 - 566



32.400 33.331 931 32.400 33.331 931 124 - 15Cyclical method

(NATM)


Tunnel section CZ 11.460 11.460

Total length of tunnel 26.531 26.531

Single-track tunnel, mining method

border tunnel "Erzgebirgstunnel" - Alternative B (short „Lohmgrundrücken“ cutting)



km 22,1+61,340 km 22,1+61,340


Table shows a comparison of the main conditions for the two alternatives, A (long cutting) and B (short cutting).

Table 8: Comparisons of Alternatives A and B


Length of permanent cutting in final state 2.340 m 680 mLength using open method (temporary cutting) 160 m 460 mTotal length of temporary cutting 2.500 m 1.140 m

Excavation volume for permanent cutting 1.443.783 m³ 152.641 m³Excavation volume for open method (temporary cutting) 312.479 m³ 1.147.461 m³

Volume of filling after open method 219.339 m³ 968.091 m³Filling volume for embankments 986.792 m³ 698.355 m³

Total length of border tunnel 24.645 m 26.531 mExcavation volume for mining method 4.100.550 m³ 4.373.460 m³Number of cross/connecting tunnels 60 pc. 65 pc.Total length of cross tunnels 1.800 m 1.950 mExcavation volume for cross tunnels 32.400 m³ 35.100 m³

Alternative A Alternative BComparison of Alternatives A and B


3.2.7 Loading gauge and design of cross-section and emergency stopping point

3.2.7.1 Loading gauge and design of cross-section

The loading gauges are determined by the planned use and are specified in regulations at national (DB Guideline 853) and international (TSI Infrastructure and/or TSI Safety in railway tunnels) level. In connection with the loading gauge and design of cross-section, the follow-ing infrastructural elements were taken into consideration:

Standard clearance for overhead lines as specified in Ril 997.0101

Loading gauge GC as specified in Ril 800.0130

Gauge line G2 as specified in EBO

Safety room as specified in GUV-V D 33

Escape route as specified in the EBA Guideline entitled „Anforderungen des Brand- und Katastrophenschutzes an den Bau und den Betrieb von Eisenbahntunneln“ (Fire and catastrophe protection requirements for the construction and operation of railway tunnels)

The delimitation of the inner load-bearing structure was based on the following specification drawings in Ril 853.9001:

Open construction

Ril 853.9001 - similar to T-R-O-R-1-01

Figure 30: Cross-section - open construction


Shotcrete method (NATM)

Ril 853.9001 - T-F-B-M-1-01

Figure 33: Cross-section – shotcrete method (NATM)

Mechanized method

Ril 853.9001 - T-F-B-K-1-01

Figure 31: Cross-section – mechanized method


Inner shell

Mechanized tunnelling using a TBM produces a circular cross-section, whereas the conven-tional NATM method results in an elliptical cross-section.

The inner dimensions represented in the planning documents conform to DB regulations (Guideline 853) which are also TSI-conformant.

The dimensions of the inner shell of the tunnel result from structural design requirements that depend on the load-bearing capacity of the surrounding rocks as specified in the results of the geological exploration and the expert report (report on tunnel construction technology). For this reason, from-to values are given in the planning documents as examples of the thicknesses of the interior shell.

Excess profiles result from the geological conditions as described in the expert report and/or on the decisions on the tunnelling method to be used (conventional NATM or mechanized tunnelling using a TBM).

3.2.7.2 Emergency stopping point (NHS)

The safety measures required by the relevant regulations and norms for the construction of new railway tunnels in Germany, Austria and Switzerland normally refer to tunnels up to 20 km long. In very long tunnels, the travelling time of a train exceeds the duration of assured running characteristics under fire conditions (15 minutes at a minimum of 80 km/h [23]). Very long tunnels therefore require special safety measures which must be decided in each indi-vidual case [20].

TSI LOC&PAS 2011/201/EU

In TSI LOC&PAS [23], Section 4.2.10.4.4, the operability of a train is specified as follows:


According to TSI LOC&PAS, the vehicle unit must guarantee the required duration of the assured running characteristics of a train under blazing fire conditions, i.e. 15 minutes at a minimum of 80 km/h in order to reach a “place suitable for firefighting”. This requirement re-sults in an assured (theoretical) travelling distance of 20 km.

This means that the requirement for a suitable place for firefighting cannot be fulfilled in tun-nels over 20 km long, since in theory a burning train could come to a stop inside the tunnel.

A binding agreement about the consequences of this core requirement for this project must be made during the next stage of planning, between the railway infrastructure companies SZDC and DB Netz AG, the construction authorities in CZ and DE and the relevant fire and catastrophe protection organizations.

TSI-SRT 2014/356/EU

Furthermore, vehicle categories are specified as follows in Section 4.2.1 TSI-SRT 2014/356, subsystem “Vehicles”:

TSI-SRT 2014/356, subsystem “Infrastructure”, Section 4.2.1.7 Firefighting points, contains the following specifications:


From this it can be seen that the maximum distance between firefighting points for category B must not exceed 20 km. Further requirements for firefighting points are:


Swiss norm SIA 197/1

The Swiss norm SIA 197/1 [38] makes a concrete recommendation for emergency stopping points (NHS) in very long tunnels.


Emergency stopping areas in tunnels under construction

The length of the emergency stopping areas is calculated based on the maximum length of a passenger train. Safety aspects of the new railway tunnels through the Alps (Lötschberg, Gotthardt, Brenner, Semmering, Koralm Tunnel) are collected in [26] and [27]. For compari-son, because of the length of that tunnel and its relevance to the current situation, the dia-grams below represent the emergency stopping point (NHS) concept for the Koralm Tunnel.

Figure 32: System diagram for the Koralm Tunnel [29]

Figure 33: Emergency stopping point, Koralmtunnel [26]


The tunnel has a roof like longitudinal profile. From its highest point the tunnel crest, around 13 km from the northern portal, the gradient falls at 5.083 ‰ towards the north portal and 4.00 ‰ towards the south portal. The emergency stopping point is almost in the middle of the tunnel and represents an area with increased safety levels in the event of an incident.

Figure 34: Cross-section of emergency stopping point, Koralm Tunnel [29]

Design features of the emergency stopping point (NHS) of the Koralm Tunnel [26]:

Emergency stopping areas with emergency platforms on the inside of the main tunnel symmetric to the tunnel axis with a length of 400 m

Nine connecting points at intervals of ca. 50 m between the emergency stopping are-as and the central tunnel

A central tunnel as a waiting area

Two ventilation tunnels connected with the main tunnels at each end of the central tunnel

Two air supply shafts, one in Leibenfeld (around 60 m deep) and one in Paierdorf (around 120 m deep) near the main tunnel portals

An air supply station in each of the air supply shafts.

Conclusion:

In Austria and Switzerland, in projects involving tunnels with structures longer than 20 km, tunnel systems with two single-track main tunnels connected by cross tunnels and with ap-propriate emergency stopping points (NHS) have become standard. The choice of a suitable emergency stopping system must be made individually for each long tunnel project.

As part of the further planning process, a concept for a suitable emergency stopping system for the border tunnel on the new Dresden-Prague railway line must be developed.


3.2.8 Design principles for tunnel lining, drainage and sealing and for structural fire protection

3.2.8.1 Tunnel lining

Tunnel linings are subdivided into single-shell and two-shell constructions. The final finishing of mechanically bored tunnel structures is usually single-shell. In contrast, the shotcrete shell (outer shell of the tunnel) created in the NATM usually serves as a temporary support for the excavation cross-section. The inner tunnel shell is constructed afterwards.

Apart from the process-related conditions, the decision on single- or two-shell finishing is influenced by other important parameters. This decision is determined by the geological and hydrological conditions and by the requirements for impermeability, structural stability and fire protection that apply to the tunnel. Table below contains further criteria which influence the decision on tunnel lining construction from a structural and cost-effectiveness point of view.

Figure 35 shows two examples of cross-sections for single- and two-shell tubbing lining.

Figure 35: Examples of single- and two-shell tubbing linings [1]

The decision on the construction method determines the size of the tunnel excavation cross-section, the type of sealing and the fixing technology for equipment for the tunnel structure.


Table 9: Comparison of single-/two-shell linings with regard to structural and cost-effectiveness/construction procedure aspects [1]

In Germany, machine-driven tunnels of diameter D 5,50 m are mostly constructed with an impermeable single-shell tubbing lining. In Austria and Switzerland, in contrast, two-shell construction with tubbing (outer shell) and subsequent installation of a normally unreinforced inner shell is a standard construction method, also for railway tunnels of large diameters [1].

For railway tunnels constructed mechanically and with tubbing lining, according to the Guide-lines in Guideline 853 [16], a single-shell lining should normally to be used where the ge-otechnical and construction conditions permit this and where it would lead to advantages in terms of cost-effectiveness. Two-shell linings should be chosen in the following cases: [16]

In a “chemically very aggressive environment” (XA 3) as specified in DIN EN 206-1, since with current technology, durability of the final state can only be achieved in such cases by means of an inner shell protected by synthetic sealing membranes

Where loads are extreme (e.g. high vertical pressure combined with low lateral pres-sure, low or non-existent water pressure and poor lateral embedding), so that the tubbing lining alone does not provide the reserve load capacity that is required in the final state


Where very high water pressures (significantly higher than 6 bar) combined with high water flows mean that the required level of impermeability cannot be reliably and permanently achieved using a single-shell tubbing lining.

In deviation from the recommendations described above which are contained in the Guide-lines in Guideline 853, single-shell tubbing linings were used for the first time in Germany in the Katzenbergtunnel with water pressures exceeding 6 bar. The assumed water pressure for the Katzenbergtunnel is 9.0 bar.

The table below shows some reference projects in Germany with single-shell tubbing linings.

Table 6: Tunnels in Germany with single-shell tubbing linings - main parameters [11]

The Guideline to Guideline 853 also states that the storage, operational and staff rooms as-sociated with tunnel structures must meet the requirements for impermeability class 1, but this cannot be achieved using single-shell tubbing linings [16].

Länge Ø Innen Ø Außen Tübbing-dicke

Tübbing-breite

Wasser-druck

[m] [m] [m] [cm] [m] [bar]Köhlbrandtunnel, Hamburg Leitungen 1996-1997 382 2,37 2,82 25 1,0 3,6Abwasserdruckleitung (ADL)TunneI, Berlin Leitungen 2000-2003 5.360 3,00 3,54 22 1,2 3,0BEWAG-Kabeltunnel, Berlin Leitungen 1995-2001 8.545 3,08 3,54 23 1,2 3,5Sammler Wilhelmsburg Los I + II, Hamburg Sammler 1974-1978 4.555 3,70 4,43 32 0,8 2,0Pegnitztalsammler Nürnberg. BA IV, Los 2 Sammler 1996-1997 490 4,40 4,90 25 1,2 1,8Fernwärme-Verbundtunnel München, Los 1-3 Leitungen 1988-1991 5.400 4,40 5,00 30 1,2 3,0Hera-Tunnel, Desy Hamburg Forschung 1985-1987 6.300 5,20 5,80 30 1,2 -U-Bahn Nürnberg, U2 Nord, Wöhrder Wiese U-Bahn 1988-1989 1.854 5,40 6,00 30 1,2 2,5Stadtbahn Duisburg, TA 7/8A Stadtbahn 1994-1998 6.206 5,62 6,40 35 1,1 1,5U-Bahn Berlin, Baulos D79 U-Bahn 1985-1989 2.160 5,70 6,40 35 1,1 1,4U-Bahn Berlin, Baulos H110 Stadtbahn 1981 1.141 5,70 6,50 40 1,5 1,9Nord-Süd Stadtbahn Köln, Los Nord Stadtbahn 2006-2007 522 5,70 6,32 30 1,2 1,5Stadtbahn Köln, Baulos M1 Stadtbahn 1992-1994 2.480 5,72 6,32 30 1,2 2,5Stadtbahn Duisburg,TA 6, Baulos 22 Stadtbahn 1988-1990 100 5,72 6,32 35 1,5 3,3U-Bahn Berlin, U5, Baulos 3.1 U-Bahn 1998-1999 978 5,75 6,45 35 1,2 1,6Flughafen-S-Bahn Hamburg S-Bahn 2004-2006 3.481 5,80 6,60 40 1,5 (1,4) 2,5Stadtbahn Mülheim BA8, Ruhrtunnel Stadtbahn 1989-1991 2.130 5,90 6,60 35 1,2 3,2U-Bahn München, U5/9-5,Theresienwiese U-Bahn 1979-1981 1.560 6,05 6,20 32,5 1,2 2,0U-Bahn München, U8/1-7.1, Fraunhoferstraße U-Bahn 1974-1976 2.310 6,20 6,90 35 1,0 2,2U-Bahn München, U3-Nord, Los 2, Moosach U-Bahn 2007-2008 2.388 6,30 2,10 35 1,5 1,0U-Bahn München, U 1 -West, Los 5, Gern U-Bahn 1994-1995 2.344 6,40 2,10 35 1,5 -U-Bahn München, U2-Ost, Los 1,Josephsburg U-Bahn 1994-1996 3.700 6,40 2,10 40 1,5 3,0Stadtbahn Essen, Los 34 Stadtbahn 1991-1996 4.200 7,27 8,02 40 1,5 3,1Nord-Süd Stadtbahn Köln, Los Süd Stadtbahn 2006-2007 5.380 7,30 8,10 40 1,5 2,5CityTunnel Leipzig, Los B Eisenbahn 2006-2009 2.930 7,90 8,20 40 1,8 2,0Fernbahntunnel Berlin, Los 3 Eisenbahn 1997-2001 2.540 7,85 8,65 40 1,5 1,9U-Bahn Düsseldorf, Los K-S Stadtbahn 1998-1999 1.110 8,19 9,09 45 1,5 1,5NeuerTunnel Schlüchtern Eisenbahn 2007-2008 3.942 9,00 9,90 45 2,0 3,0Katzenbergtunnel Eisenbahn 2005-2008 17.968 9,60 10,80 60 2,0 9,0Herrentunnel Lübeck Straße 2002-2003 1.560 10,40 11,30 45 1,5 3,3Wesertunnel Dedesdorf Straße 1999-2001 3.200 10,30 11,30 50 1,5 4,04. Röhre Elbtunnel, Hamburg Straße 1997-2000 2.561 12,35 13,25 20 2,0 5,0

Art der Nutzung BauzeitTunnelbauwerk


Heidenau-Großsedlitz Tunnel

For the section of the Heidenau-Großsedlitz Tunnel that is to be constructed using mining methods, the conventional shotcrete method (NATM) [cyclical method] is suggested. As a consequence, there would be a two-shell lining with a temporary shotcrete shell (outer tunnel shell) and an inner tunnel shell made of in-situ concrete. A final decision is to be made during the further planning process.

Border tunnel (Erzgebirgstunnel)

In view of the geotechnical and hydrological investigations that are still to be carried out and the fire protection requirements that are still to be investigated, current knowledge is not suf-ficient for a final decision on the choice of a single-shell or two-shell construction. A decision must be made during the further planning process.

3.2.8.2 Tunnel sealing and drainage

When constructing a tunnel, there are two main possibilities for dealing with ground water. Firstly, the tunnel can be designed as a drained tunnel. In this case, the mountain water permeating the arched area can be fed into drainage pipes. With this permanently effective drainage system, there can be no build-up of water pressure on the tunnel lining.

Alternatively, a tunnel structure can be designed to resist water pressure. In this case, the tunnel structure and its sealing system must be designed for the water pressure that is actu-ally present.

Because a drained tunnel structure permanently drains the surrounding subsoil, leading to a reduction in ground water level, it has a major impact on the water balance and thus on the ecological systems in its environment. From an environmental point of view, this can mean that the tunnel structure must be made impermeable so that natural mountain water condi-tions are not affected after the construction project has been completed.

Ril 853 [15] states that new railway tunnels must be made pressure-tight by means of an all-round sealing. If only water is present that can trickle away into the rock with no backwa-ter pressure building up, an umbrella seal is permitted. The fact that the water can trickle away without backwater pressure building up must be confirmed by an geological expert [15].

The design of the seal itself depends on the prevalent water pressure and the chemistry of the mountain water.


Mining method (NATM)

In the seepage water area and with a water pressure corresponding to a 30 m water column, two alternatives are possible. Ril 853.4101 does not specify a standard construction where the mountain water is mildly to moderately aggressive to concrete, but allows a choice be-tween sealing using synthetic sealing membranes (called KDB) and a design that uses wa-ter-impermeable in-situ concrete (called WUBK). Where the water pressure is greater than a 30 m water column and/or the mountain water is very aggressive to concrete, it specifies a combination of WUBK and KDB. Where the water pressure exceeds a 60 m water column, tunnel sealing must fulfil more stringent requirements. Figure 36 contains an overview of the sealing methods for tunnels constructed using mining methods.

Figure 36: Sealing methods as specified by Ril 853 [15]


Figure shows the requirements for the sealing of joints in each sealing method, as specified by Ril 853.

Figure 40: Requirements for the sealing of joints as specified by Ril 853 [15]

Figures 41 and 37 below show a comparison of the regulations for sealing in tunnels con-structed using mining methods as specified by ZTV-ING and öbv Guideline respectively.

Figure 41: Sealing of joints as specified in ZTV-ING Part 5, Para. 5, Tab. 5.5.3 [17]


Figure 37: Sealing of joints as specified in öbv Guideline „Tunnelabdichtung“ [18]

Mechanized tunnelling

In Germany, railway tunnels constructed using machines usually have a single-shell tubbing lining. This method is being or has been used for the following Deutsche Bahn tunnels: Neue Schlüchterner Tunnel, Katzenbergtunnel, Finnetunnel, Neue Kaiser-Wilhelm-Tunnel. For the sealing of tunnels with single-shell tubbing linings, Module 853.4005 of DB Guideline 853 is applicable.

Two-shell linings consisting of an outer tubbing shell and an inner shell made of in-situ con-crete represent special cases [16].

Alkali-aggregate reaction (AAR)

When excavated material is used in concrete production, further requirements on the sealing membrane may result. As described in Chapter 3.2.5.3, some types of rock such as gneis, siliceous limestone and granodiorite can behave unfavourably with respect to the alkali-aggregate reaction. As a consequence, in the Lötschberg Base Tunnel, the concrete in areas with infiltrating mountain water was given additional protection by the installation of sealing membranes [13].

The final decisions on the sealing systems must be made during the further planning process on the basis of the expert geotechnical and tunnel construction reports and of the hydrogeo-logical and chemical investigations.


3.2.8.3 Structural fire protection

The principles of fire and catastrophe protection are defined in Ril 853 [15], Ril 123 [41], TSI-SRT [21] and the EBA Guideline „Anforderungen des Brand- und Katastrophenschutzes an den Bau und den Betrieb von Eisenbahntunneln“ (Fire and catastrophe requirements for the construction and operation of railway tunnels) [20].

From a technical point of view, there are different ways of ensuring the structural stability of a single-shell tunnel lining in the event of a fire:

cladding with fire protection panels or fire protection plaster

large-scale fire tests

structural stability calculations that take into consideration the concrete spalling that is to be expected during a fire.

Fire protection cladding is basically suitable for ensuring structural fire protection, but has disadvantages with regard to structural inspections. Furthermore, the useful life of fire protec-tion cladding is usually limited to 25 to 35 years [40]. Where the intended useful life of a civil engineering structure is 100 years, the fire protection cladding would need to be renewed twice or three times.

Because of this, adequate fire protection should normally be proved by calculations or by fire tests. Ril 853 [15] contains the following specifications:

Tunnels with inner shells made of in-situ concrete and tunnels constructed using the open method

For tunnels with inner shells made of in-situ concrete and tunnels constructed using the open method with rectangular frames, the structural stability of the tunnel in the event of fire must be proved in each individual case. Proof must be provided either in the form of calculations or by means of fire tests [15].

Tunnels with single-shell tubbing linings

The structural stability of a single-shell tubbing lining during and after a fire must be proved by calculations. Calculations are not necessary if fire tests prove that the test specimen is stable during testing. The proof of structural stability must take the expected concrete spall-ing into consideration [15].


3.2.9 Type and positioning of the safety and rescue systems

Taking the technical regulations of TSI Safety in Railway Tunnels and the EBA Guideline on fire and catastrophe protection into account, concepts for fire and catastrophe protection both during construction and in the final state must be developed in cooperation with the respon-sible units at DB Netz AG and SŽDC. The minimum structural requirements are described as follows in TSI 1303/2014 „Safety in Railway Tunnels“.

3.2.9.1 Subsystem Infrastructure (structural measures)

Fire protection requirements for tunnel construction materials

Fire detection

Evacuation systems

Self-rescue, evacuation, rescue

safe area in the case of adjacent single-track tunnels

emergency exits into the open air (max. distance 1000 m)

not necessary where cross tunnels at intervals < 500 m lead into the neighbouring tunnel (clear height > 2,25 m, clear width > 1,50 m), door openings clear width > 1,40 m, clear height > 2,00 m and with lighting and emergency signs

Escape Routes

W > 80 cm, H > 2,25 m, handrails between 0,80 m and 1,10 m above the escape route floor

Emergency Lighting on escape routes

1 lx for 90 minutes above the escape route

Emergency Signs

Intervals < 50m, indicating emergency exits and lengths of escape routes

Fire Fighting Points

Intervals of 5 km (Category A) or 20 km (Category B) in the tunnel (emergency stopping point)

Fire fighting water supply of 800 l/min (over 2 hours)

Emergency communications

GSMR

Access for the emergency services

Portal / emergency exit, clear width > 2,25 m, clear height > 2,25 m


Escape area outside the tunnel

A = 500 m² (EBA Guideline specifies 1.500 m²)

Only in EBA Guideline „Fire and catastrophe protection in railway tunnels“

Vehicular use of tracks

Vehicle access for fire and catastrophe services to the tunnel portals / emergency ex-its and suitability of track superstructure for use by fire and catastrophe service vehi-cles

3.2.9.2 Subsystem Energy

Overhead line sections max. 5 km

Earthing equipment at the tunnel entrances

Power supply for emergency services

Behaviour of cables in the event of fire

Protection of electrical installations

3.2.9.3 Subsystem Train Management

Hot axle-box detectors in front of the tunnel structure

3.2.9.4 Technical measures for planned long tunnel structures

Video monitoring in technical control centre

Temperature measurements in the tunnel

Smoke and heat detectors

Tunnel air supply and ventilation in the event of emergency

Underground emergency stopping point for trains (L= 450m) in tunnels over 15 km long, with escape tunnels between the tunnel tubes and evacuation using a rescue train in the adjacent tunnel

for details see Chapter 3.2.7.2 “Emergency stopping point (NHS)“


3.2.10 Logistics concept

The logistics concept for the access to the construction site and for the material transport depends largely on the selected construction method TBM or NATM and must be developed accordingly. All aspects of the existing infrastructure conditions must be investigated.

At the actual planning stage the construction sites of the new railway line are accessible through the public road network.

Areas for the temporary implementation of construction facilities for the technical equipment the housing for workers are usually sought at open spaces near the construction site that are easily accessible and can be removed after the construction of the railway line has been fin-ished.

Specific areas have to be checked for the environmental impact of these facilities according federal laws.

Figure 38: Plan view of Northern area of the New Railway Line

For the cross border tunnel it is necessary to provide a larger area particularly to establish a production site for the manufacturing of tunnel lining material (Tübbinge etc.) and establish-ing a treatment plant for the recyclable material excavated from the tunnel boring. A possible area for the building site equipment area is the landscape area along the local street S173 between “Zehista” and “Cotta” which has been zoned as a future area for a commercial area.


Figure 39: Plan view of the area at Börnersdorf

A second access to the tunnel can be constructed north of the municipality of Breitenau where rescue facilities are planned according to the provisions of the federal railway agency EBA. It is planned to build additional technical buildings for the power supply of the cross border tunnel, a ventilation station and an access road (expansion of a rural road) towards motorway A 17. This vertical shaft will function as a future access point for firefighters and rescue workers. During construction of the tunnel the shaft is also used for the transportation of the tunnel excavation material.

Figure 40: Plan view of the area at Chlumec


At the south portal of the cross border tunnel equivalent facilities for the construction and the later operation and maintenance of the tunnel will have to be constructed. Access to this area is possible through the existing road network.

3.2.11 Analysis of geotechnical and construction method risks

„Risk is understood to mean the possibility that the procedures initiated by a decision may not necessarily lead to the intended objective and that positive or negative deviations may occur“ [1]. Risks can be quantified by determining their extent (extent of damage) and the probability of their occurrence.

During the further planning processes for the planned „New Dresden-Prague railway line“ infrastructure project, an appropriate risk management system to deal with such deviations from the objectives must be planned. As an example, we refer to the risk analysis carried out by AlpTransit Gotthard AG which was applied to the Gotthardt Tunnel. Risk identification, risk analysis and classification and risk control must be carried out in sub-processes. Elements for risk management include, for example:

Risks involved in the construction, railway and environmental technology planning

Cost calculation risks

Risks involved in the tender and contract awarding procedures

Contractual risks

Authorization risks

Risks associated with the construction method and construction execution

Deadline risks

Resource risks.

In connection with risk management, we also refer to the CSM directive of the European Commission, Directive (EG) No. 352/2009, Official Journal of the European Communities dated 29.4.2009.

The risk analysis must be updated at regular intervals during the planning process to reflect the planning results. Risk management throughout the planning process serves to help rec-ognize opportunities and risks and to reduce or as far as possible avoid the risks by taking appropriate measures.


3.2.12 Assessment of the feasibility of the chosen tunnel solution

(Securing measures, rights to tender, supply and waste disposal systems, ventilation during construction, environmental impacts, construction peri-od and construction cost criteria, environmental aspects with regard to ground water balance and dumping)

Heidenau-Großsedlitz Tunnel

The Heidenau-Großsedlitz Tunnel, which consists of two sections separated by cuttings with a total length of 1.790 m (west) and 1.710 m (east), is to be constructed conventionally using the shotcrete method (cyclical driving). The entrance areas are to be constructed using the open method up to a roof coverage that is to be determined based on cost-effectiveness and tunnel construction technology criteria. Tunnelling can take place in multiple locations at the same time. Further decisions can only be made with more exact knowledge of the conditions.

Cross Border Tunnel (Erzgebirgstunnel)

Because of its length, the geology and its structure with two single-track tubes 24.645 m long, the base tunnel is expected to be constructed mechanically. Several TBMs will be used in order to achieve an acceptable construction period. The type of TBM depends on the ge-ology and the hydrogeological conditions. In principle, the use of the conventional blasting method (cyclical driving, shotcrete method) is also possible. Especially in the southern and northern sections of the base tunnel where the geology is not homogeneous, conventional (cyclical) tunnelling using the shotcrete method is also conceivable as an alternative to mechanized tunnelling. If mechanized tunnelling were to be used in these areas, the TBMs would have to be different from those used for the central tunnel area. TBMs that can be ad-justed to different geological conditions could also be used. A decision on the optimal tunnel-ling method and on the selection of suitable TBMs must be made in a later planning phase.

At the current planning stage of this project an exact assessment of the feasibility of a chosen tunnel solution is not possible since most of the above mentioned basic geological and hydrological data is yet to be defined in the next planning step. Hence the environmental impact of the tunnel construction also needs to be determined in the following planning step.


Literature / Sources [1] Betonkalender 2014 „Unterirdisches Bauen, Grundbau, Eurocode 7“

Ernst & Sohn (2014) – ISBN: 978-3-433-03051-6

[2] Guideline für die geotechnische Planung von Untertagebauten mit kontinuierlichem Vortrieb Österreichische Gesellschaft für Geomechanik - ÖGG (2013)

[3] Guideline für die geotechnische Planung von Untertagebauten mit zyklischem Vor-trieb 2. überarbeitete Auflage Österreichische Gesellschaft für Geomechanik - ÖGG (2008)

[4] Bauprozesse und Bauverfahren des Tunnelbaus Ernst & Sohn (2013) – ISBN: 978-3-433-03047-9

[5] Maschineller Tunnelbau im Schildvortrieb Ernst & Sohn (2011) – ISBN: 978-3-433-02948-0, 2. Auflage

[6] Empfehlungen zur Auswahl von Tunnelvortriebsmaschinen Deutscher Ausschuss für unterirdisches Bauen e. V. - DAUB (2010)

[7] Geotechnik – Tunnelbau und Tunnelmechanik Springer (1998) – ISBN: 3-540-62805-3

[8] http://www.bahnprojekt-stuttgart-ulm.de/uploads/tx_smediamediathek/ S264_Durchbruch01_WAF_Katzenbergtunnel.jpg

[9] TBM versus NATM from the contractor’s point of view TBM versus NÖT aus Sicht des Unternehmers Ernst & Sohn (2011) – Geomechanics and Tunnelling 4 (2011), No. 4

[10] NATM and TBM – comparison with regard to construction operation NÖT und TBM – eine baubetriebliche Gegenüberstellung Ernst & Sohn (2011) – Geomechanics and Tunnelling 4 (2011), No. 4

[11] Einschalige wasserundurchlässige Tübbingauskleidungen in Deutschland Single-Shell watertight segmental Linings in Germany Tunnel (2009) – Ausgabe 03/2009

[12] Wirtschaftliche Aspekte bei Tunnelbauwerken in frühen Planungsphasen Hessisches Landesamt für Straßen- und Verkehrswesen (2005) – Heft 52-2006

[13] Alpenquerende Tunnel Materialbewirtschaftung und Betontechnologie beim Lötschberg-Basistunnel Beton- und Stahlbetonbau (2007) – 102 Heft 1


[14] Alp Transit Ausbruchmaterialbewirtschaftung am Gotthard und am Lötschberg Mitteilungen der Schweizerischen Gesellschaft für Boden- und Felsmechanik (1993)

[15] Guideline 853 - Eisenbahntunnel planen, bauen und instand halten DB Netz AG – 8. Aktualisierung (10/2014)

[16] Leitfaden zur Guideline 853 – Kommentare und Planungshilfen zur Ril 853 DB Netz AG – 5. Aktualisierung (10/2014)

[17] ZTV-ING - Zusätzliche Technische Vertragsbedingungen und Guidelinen für Ingeni-eurbauten, Stand 12/2014

[18] öbv Guideline „Tunnelabdichtung“ öbv Österreichische Bautechnik Vereinigung – Ausgabe Dezember 2012

[19] Strecke 6604, Cottaer Tunnel - Bilder Tunnelportale und Zeichnungen http://www.eisenbahntunnel-portal.de/lb/inhalt/tunnelportale/6604.html

[20] EBA Guideline „Anforderungen des Brand- und Katastrophenschutzes an den Bau und den Betrieb von Eisenbahntunneln“ Eisenbahn-Bundesamt – Stand: 01.07.2008

[21] TSI SRT „Sicherheit in Eisenbahntunneln“ VO (EU) 1303/2014 – In Deutschland in Kraft seit: 01.01.2015

[22] TSI INF „Infrastruktur“ VO (EU) 1299/2014 – In Deutschland in Kraft seit: 01.01.2015

[23] TSI LOC&PAS „Fahrzeuge - Lokomotiven und Personenwagen“ VO (EU) 1302/2014 – In Deutschland in Kraft seit: 01.01.2015

[24] UIC-Codex 779-9 „Sicherheit in Eisenbahntunnel“

[25] “RECOMMENDATIONS OF THE MULTIDISCIPLINARY GROUP OF EXPERTS ON SAFETY IN TUNNELS (RAIL)” - TRANS/AC.9/9 UNITED NATIONS, Economic and Social Council – 01.12.2003

[26] Comparison of safety and ventilation saspects of emergency stations in very long railway tunnels Sicherheits- und lüftungstechnische Gegenüberstellung von Nothaltestellen sehr langer Eisenbahntunnel Geomechanics and Tunneling (2013), No. 6

[27] Neue alpendurchquerende Bahntunnel in Europa Gegenüberstellung von bauwerks- und ausrüstungsspezifischen Merkmalen der neuen alpendurchquerenden Bahntunnel in Frankreich, Italien, Österreich und der Schweiz Christoph Rudin und Dr. Peter Reinke – Tunnel 2008


[28] Rettungs- und Brandschutzkonzept für die komplexe Untertage-Baustelle Koralm-tunnel Mag.(FH) MAS Susanne Fehleisen, Graz (Österreich) – BauPortal 4/2014

[29] The Austrian Koralm tunnel - Investigation, Design and Construction Process for a large Base Tunnel Project ÖBB – Austrian Federal Railways, Gerhard Harer

[30] Guideline 997.0101 – Oberleitungsanlagen DB Netz AG – Stand 01. Juli 2001

[31] Guideline 800.0130 – Netzinfrastruktur Technik entwerfen; Streckenquerschnitte auf Erdkörpern DB Netz AG – Stand 01.02.1997

[32] Eisenbahn-Bau- und Betriebsordnung (EBO) Stand 25.07.2012

[33] Unfallverhütungsvorschrift – Arbeiten im Bereich von Gleisen – GUV-V D 33 DB Netz AG – Stand 01. Juli 2001

[34] Brand- und Katastrophenschutz in Eisenbahntunneln Deutsche Bahn AG, Klaus Kruse – August 2003, Version 3

[35] Is the structure of Börnersdorf a possible maar-diatreme volcano? Ist die Struktur von Börnersdorf möglicherweise ein Maar-Diatrem-Vulkan? Horna, Krentz, Buske, Käppler, Börner - TU Freiberg - 2013

[36] “Geophysikalische Untersuchungen an der Struktur Börnersdorf/Osterzgebirge zur Klärung der tektonischen Situation” Krentz & Horna - Sächsisches Landesamt für Umwelt, Landwirtschaft und Geologie (LfULG) - 2014

[37] Projektierung Tunnel - Grundlagen SIA 197:2004, Schweizer Norm – Stand 2004

[38] Projektierung Tunnel - Bahntunnel SIA 197/1:2003, Schweizer Norm – Stand 2004

[39] Sicherheit in Eisenbahntunneln – Ergebnisse einer UIC-Arbeitsgruppe Tunnelbau 2003, DGGT Deutsche Gesellschaft für Geotechnik e.V. Verlag Glückauf GmbH, ISBN: 3-7739-1286-2

[40] Baulicher Brandschutz bei Eisenbahntunneln mit einschaligem Tübbingausbau Tunnelbau 2011, DGGT Deutsche Gesellschaft für Geotechnik e.V. VGE Verlag GmbH, ISBN: 978-3-86797-087-7

[41] Guideline 123.0111 – Notfallmanagement und Brandschutz in Eisenbahntunneln DB Netz AG – Stand 01.01.2006


Lists of figures and tables Figures:

Figure 1: Sketch map of the new Dresden – Prague railway line .................................... 6 Figure 2: Diagram for overtaking station ......................................................................... 8 Figure 3: Key to longitudinal geological section ............................................................ 15 Figure 4: Section of location plan, Börnersdorf fault zone ............................................. 19 Figure 5: Section of location plan, Bergkeller Pechhütte ............................................... 20 Figure 6: Section of location plan, km 12,6 – 13,4, eastern ........................................... 20 Figure 7: Section of location plan, km 12,6 – 13,4, western Burgk. Fundgrube, Richard

Grube ............................................................................................................ 21 Figure 8: Section of location plan, new Dresden-Prague line – Cottaer Tunnel ............. 22 Figure 9: Drawings of the Cottaer Tunnel [19]............................................................... 22 Figure 10: Cottaer Tunnel – northwestern portal [19] ...................................................... 23 Figure 11: Cottaer Tunnel – southeastern portal [19] ...................................................... 23 Figure 12: Starting wall of tunnel, mining method, securing with pipe roof, divided calotte

[photo: K+K] ................................................................................................... 24 Figure 13: Preliminary cut, shotcrete support with grouted anchors [photo: K+K] ........... 25 Figure 14: Tunnelling by blasting – boring the blast holes [photo: K+K] ......................... 25 Figure 15: Breakthrough of both TBMs, Katzenbergtunnel [Photo: Firma Herrenknecht

[8]] ................................................................................................................. 26 Figure 16: Cost comparison TBM – blasting method [7] .................................................. 28 Figure 17: Flow chart – dynamic decision-making process [1] ........................................ 34 Figure 18: Diagram showing the geotechnical planning procedure [2] ............................ 35 Figure 19: Diagram showing construction planning process [2] ...................................... 37 Figure 20: Conditions affecting management of excavated and blasted materials .......... 38 Figure 21: Management of excavated and blasted materials .......................................... 43 Figure 22: New Dresden-Prague railway line – surface mines in the area, Part 1 ........... 43 Figure 23: New Dresden-Prague railway line – surface mines in the area, Part 2 ........... 43 Figure 24: Organizational structure of the Upper Mining Authority of Saxony ................. 49 Figure 25: Delimitation of the open and mining (NATM) methods [12] ............................ 51 Figure 26: Part of longitudinal section - Heidenau-Großsedlitz Tunnel ............................ 52 Figure 27: Part 1 of location plan, Heidenau-Großsedlitz Tunnel .................................... 53 Figure 28: Part 2 of location plan, Heidenau-Großsedlitz Tunnel .................................... 53 Figure 29: Part 3 of location plan, Heidenau-Großsedlitz Tunnel .................................... 53 Figure 30: Part of longitudinal section – border tunnel, northern portal area (D) ............. 55 Figure 31: Part of longitudinal section – border tunnel, southern portal area (CZ)........... 56 Figure 32: Cross-section - open construction .................................................................. 60 Figure 33: Cross-section – shotcrete method (NATM) .................................................... 61 Figure 34: Cross-section – mechanized method ............................................................. 61 Figure 35: System diagram for the Koralm Tunnel .......................................................... 66 Figure 36: Emergency stopping point, Koralmtunnel ....................................................... 66 Figure 37: Cross-section of emergency stopping point, Koralm Tunnel .......................... 67


Figure 38: Examples of single- and two-shell tubbing linings .......................................... 68 Figure 39: Sealing methods as specified by Ril 853 ........................................................ 72 Figure 40: Requirements for the sealing of joints as specified by Ril 853 ........................ 73 Figure 41: Sealing of joints as specified in ZTV-ING Part 5, Para. 5, Tab. 5.5.3 ............. 73 Figure 42: Sealing of joints as specified in öbv Guideline „Tunnelabdichtung“] ............... 74 Figure 43: Plan view of Northern area of the New Railway Line ...................................... 78 Figure 44: Plan view of the area at Börnersdorf .............................................................. 79 Figure 45: Plan view of the area at Chlumec .................................................................. 79

Tables:

Table 1: Criteria for selecting tunnelling methods ........................................................ 27 Table 2: Overview of quantities –Heidenau-Großsedlitz Tunnel .................................. 40 Table 3: Overview of quantities – border tunnel Alternative A (long „Lohmgrundrücken“

cutting) ........................................................................................................... 41 Table 4: Overview of quantities – border tunnel Alternative B (short

„Lohmgrundrücken“ cutting) ........................................................................... 42 Table 5 Overview of excavation quantities in Saxony (first approach) 48 Table 6: Structural data ............................................................................................... 54 Table 7: Structural data – Alternative A (long cutting) .................................................. 57 Table 8: Structural data – Alternative B (short cutting) ................................................. 58 Table 9: Comparisons of Alternatives A and B............................................................. 59 Table 10: Comparison of single-/two-shell linings with regard to structural and cost-

effectiveness/construction procedure aspects [1] ........................................... 69 Table 11: Tunnels in Germany with single-shell tubbing linings - main parameters [11] . 70


3.3 Major bridges and viaducts

3.3.1 Required structures

On the current route, the following bridge structures are required:

Crossover Structure at Heidenau (ramp + frame construction)

Heidenau viaduct

Seidewitz viaduct

The structures are designed on the basis of DB Guideline 804.9020 – Outline planning of viaducts with pre-stressed concrete superstructures on concrete piers. In exceptional cases, where special conditions require it, it is possible to deviate from this.

3.3.2 Assessment criteria

The possible bridge systems were assessed and compared according to the following crite-ria:

rail tension

construction and maintenance costs

public acceptance

construction time.

3.3.2.1 Rail tension

When selecting bridge systems in the Deutsche Bahn AG, the application of rail expansion devices is an important assessment criterion. Rail expansion devices are very expensive, sensitive and very maintenance-intensive components. As a first principle, rail expansion devices should be avoided wherever possible.

The need for rail expansion devices must be proved by means of rail tension calculations. The results of rail tension calculations are greatly influenced by the choice of the fixed point on the bridge for the transfer of longitudinal forces (e.g. breaking + acceleration), the remain-ing expansion lengths of the bridge super structure and the planned stiffness of the pillars and foundations. According to DB Guideline 804.9020, where expansion lengths are a max-imum of 90 m, rail expansion joints are not normally needed. Where the planned expansion lengths are longer, the resulting rail tensions must be explicitly calculated.


In other comparable projects with appropriate stiffness of the foundations under the fixed point of the bridge and expansion lengths of ca. 110 m, it was possible to show by calculation that the rail tensions would be below the tension limit and thus avoid the use of rail expan-sion devices.

At the current stage of the project, due to the still relatively shallow depth of planning and the lack of information on the subsoil, a maximum expansion length of 90 m was set as the limit for the use of rail expansion devices.

3.3.2.2 Construction and maintenance costs

When considering construction and maintenance costs as a criterion, the main focus is on the selection of tried and tested standard construction methods, bridge systems and con-struction materials.

For viaducts, superstructure construction using a formwork carriage has proved successful as a standard method. This method is especially appropriate for superstructure cross-sections with constant widths and heights/thickness ratios.

For the bridge superstructures, pre-stressed concrete structures (hollow box or T-beam cross-sections) are normally used. Steel structures as truss or tied arch bridges are only considered for wide-span bridge superstructures.

When considering maintenance costs, not only rail expansion devices but also filigree com-ponent measurements, complicated joint sealing and drainage systems and similar should be avoided. Experience shows that steel structures are more maintenance-intensive than con-crete structures.

3.3.2.3 Acceptance

With regard to acceptance, impacts on private interests, the proximity of built-up areas, envi-ronmental compatibility and visual integration into the landscape must be considered and assessed.

3.3.2.4 Construction time

The construction of bridges and tunnels is normally the factor that determines the construc-tion time for the completion and start of operations of the entire project. Tried and tested bridge structures and their construction using tried and tested standard methods usually en-sure short construction times, which last but not least benefits public acceptance.


3.3.3 Bridge Structures

3.3.3.1 Crossover Structure at Heidenau

The new railway line starts at the exit point in Dresden-Heidenau (DB line No. 6240 NL-km 49.970) as a two-track existing section with crossovers. This is followed by re-routing of only one track on the existing DB line No. 6240 towards Pirna. In future, the re-routed track is to be used in both directions. Once it has reached a sufficient distance from the tracks of the future new line has been reached, the new line starts to ramp upwards parallel to DB line No. 6239 (city railway).

At the end of the ramp, the tracks of the new line have reached a height at which the new single-track bypass section can pass under them.

3.3.3.1.1 Ramp Structure The future ramp structure lies between the city railway line and the re-routed track of DB line No. 6240. It consists of reinforced concrete retaining walls on both sides and is filled with earth. The ramp width of 12.10 m takes into account the distance between track centres on the new line (4.00 m), corridors on each side for masts for the overhead lines and service paths on each side for route and structural inspections.

The requirements of DB Guideline 800.130 for the minimum side distance from the adjacent city railway track and from the new bypass track on DB line No. 6240 were taken into con-sideration here.

The planned longitudinal gradient of 12 ‰ to the required clear height of the adjacent cross-over structure results in a ramp length of ca. 600 m.

3.3.3.1.2 Crossover structure At ca. NL-km 0.5+14 the elevated new line starts to cross over the re-routed track on DB line No. 6240. The crossover structure is to be constructed as a reinforced concrete frame with lateral openings in its walls. The minimum required clear height above the track which pass-es underneath is set at 6.15 m above the top of the rail. Possible optimization must be agreed with the responsible specialist services during the course of further planning and on the basis of the different regulations.

The crossover structure extends from NL-km 0.5 +14 to 0.7+95 with a length of 281 m. It has structural joints at regular intervals of ca. 10 m. The block joints are made waterproof using elastic joint tapes.

Rail expansion devices are not required on the structure.


3.3.3.1.3 Construction Construction cannot start until the new bypass track has been put into operation. Operations on the city railway line must also continue during the construction period.

This means that the site of the ramp structure and of part of the crossover structure will effec-tively be an island shaped construction place with difficult access. The slab of the crossover structure must be built over the overhead line on the bypass track which will be still in opera-tion. A construction method using prefabricated reinforced concrete beams with in-situ con-crete grouting would be possible.

The difficult conditions resulting from building next to and over operational lines must be tak-en into consideration when calculating the construction time and costs.

3.3.3.2 Heidenau Viaduct

Immediately after the crossover structure described above, the new line continues as an ele-vated section crossing the Heidenau industrial park between the main line and the B 172 road.

In the current planned route, the maximum height of the rails will be ca. 15 m above ground surface.

The bridge concept is based on concrete piers and pre-stressed concrete superstructures.

The required bridge structure is initially designed with a 2-track superstructure with increas-ing bridge width as the distance between track centres on the new line gradually widens. Later on, the viaduct splits into two single-track superstructures. The point where the bridge divides into two single-track superstructures was chosen so that these can be inspected on both edges of the bridge using special bridge inspection vehicles. The route of the section with single-track bridges includes both transition curves and constant track radii. The associ-ated track cants vary accordingly. For a cost-effective construction process, the single-track bridges have a constant bridge cross-section over their entire length which is based on the maximum track cant.

The main constraints on the concept and also on later maintenance of the viaduct are repre-sented by the existing buildings in the industrial park. The B 172 road must also be crossed.

The route continues in a cutting until it reaches the portals of the Heidenau tunnel. Because of the slanted cut into the steeply climbing terrain, expensive retaining walls will be needed along both tracks. Extensive slope areas will also be created.

Because of this, two alternative concepts for the viaduct were investigated and assessed.


3.3.3.2.1 Alternative 1

Alternative 1 has a constant span width of 44,0 m over the entire length of the bridge in ac-cordance with DB AG regulations.

Within the two-track bridge cross-section with varying distances between the track centres, the superstructure is built using ground-based falsework. Because of the varying superstruc-ture width, other construction methods are either not cost-effective or not technically feasible. The structural system provides for a chain of continuous beams each with span widths of 2 x 44,0 m. The fixed point in a longitudinal direction is on each of the centre piers. As a result, rail expansion devices will probably not be necessary.

On this section of the bridge, the positioning of a pier at NL km 0,9+60 near a relatively new storage building is unavoidable. Operations in this building must therefore be discontinued and an equivalent substitute must be made available elsewhere. In view of the constant in-tervals between piers, moving the position of the pier would not lead to the desired result, since every other position would affect the property in the same way.

Fig. 1: Storage building in the Heidenau industrial park

Other buildings will be built over with a very small distance estimated at ca. 1-2 m between the roof of each building and the underside of the bridge. If these buildings remain in place, construction of the bridge can be expected to be difficult. The heights of the buildings have only been roughly estimated at the current stage of planning. The exact values must be de-termined during the next planning phase.


Fig. 2: Fly over a building at the Heidenau industrial park

The following 2 x single-track bridge area is planned with the same structural system as de-scribed above, without rail expansion devices. The positions of the bridge ends have been adjusted to the slanting and steeply climbing terrain.

The existing B 172 road will be built over with bridge piers and the required slopes at the bridge abutments. The position of the road must be slightly altered here.

Fig. 3: Cross-section of single-track bridge



The position of the piers in the concept in Alternative 2 takes into account the existing build-ings in the industrial park and the existing B 172 road.

As a consequence, constant intervals between the piers are not possible. There are different span widths over the course of the bridge and their feasibility must be ensured by selecting appropriate structural systems.

In the two-track bridge section, a span width of ca. 80 m is required to pass over the storage building mentioned above. To reduce the required thickness, this bridge span is positioned within a 3-span continuous beam. For structural reasons, both the adjacent spans must be at least ca. 58 m long. This results in a total length of the continuous beam system of 196 m. The fixed point in the longitudinal direction is located on an interior pier so that an expansion length of at least 138 m results. This means that one rail expansion device will be needed on each track.

Regardless of this, the route must pass over the storage building with a minimal clear height above its roof. To minimize the thickness over the building, the bridge cross-section must be elevated and vaulted towards the piers. It will not be possible to build the superstructure over the building using normal scaffolding. The superstructure must be constructed on temporary piers at the side of the building and then slid onto the permanent piers.

Where the superstructure consists of hollow pre-stressed concrete boxes, there must be a minimum distance of 5-6 m between the roof of the building and the top of the rails. Other-wise, the superstructure must be built with its load-bearing system above it, e.g. as a truss bridge or tied arch bridge.

The exact height of the building is not yet known and must be determined during the course of the further planning process.

Fig. 4: Passing over the storage building in Heidenau industrial park


The rest of the 2 x single-track bridge section must also be built with varying spans and con-tinuous beam lengths of 198 m (Dresden-Prague track) and 239 m (Prague-Dresden track). A rail expansion device will be required at each end of the bridge.

As in Alternative 1, the other existing buildings will probably be built over at a very low height.

The B 172 federal road remains unaltered but a retaining wall parallel to the road will be needed to secure the abutment slopes.

3.3.3.2.3 Assessment of alternatives

Alternative 1 Alternative 2

Two-track bridge length 220 m 196 m

Single-track bridge length 220/264 m 198/239 m

Rail tension + -

Construction/maintenance costs + -

Acceptance - -

Construction time + -

Result +++ - - -


3.3.3.2.4 Summary

Alternative 1 has significant advantages over Alternative 2 in terms of construction technolo-gy, costs and construction time.

However, from a superficial point of view, acceptance as a criterion has priority in the case of the Heidenau viaduct. Because of the land/sites required and the need to pass over existing buildings, both alternatives have a massive negative impact on private interests. This situa-tion is considered to represent a high risk in terms of eligibility for construction permission. This still applies to Alternative 2 in which the storage building mentioned above could possi-bly remain in place with no structural alterations.

Despite the expected compensation payments required, we must recommend Alternative 1. In this context, basic coordination with the private parties involved should take place even before the planning assessment is carried out.


3.3.3.2.5 Geology

The Heidenau viaduct will run along the vicinity of the underground cavity „Bergkeller Pechhütte“. Possible influences on the foundation of the structure must be determined and assessed as part of an expert geological report.

In the transition area between the viaduct and the Heidenau tunnel, there will be wide cutting areas with the associated major earthworks. To minimize the width of the cuttings, ground explorations are also necessary here to establish the stability of the slopes.

Fig. 5: Diagram showing the location of “Bergkeller Pechhütte”

3.3.3.3 Seidewitz viaduct

Between NL km 3,6 and 4,9, the new line is elevated to a maximum of ca. 41 m above ground. It spans the valley of the River Seidewitz and the outskirts of the district of Zehista (industrial park) by means of a viaduct. The planned Pirna bypass (B 172n road) is a con-straint. It is affected in the area of the road embankments.

The line passes over the edge of the industrial park at great height. Piers are to be posi-tioned in existing open areas and/or yard areas. Buildings are not affected.

Because of the relatively great height and length of the bridge and in order to reduce the number of piers, an interval of 58,0 m between piers was chosen for the Seidewitz viaduct. This is also a standard interval in the DB AG network.


In the area of the bridge, the route of the line changes from being straight to a curve to the right with R = 1.200 m. With the planned constant distance between track centres of 4,50 m and taking the routing and cant into account, the resulting width of the bridge superstructure ranges from 13,45 m on the straight track to 13,705 m in the curve. It is possible to inspect both sides of the bridge using a bridge service vehicle.

Fig. 6: Standard cross-section, Seidewitz viaduct

Two alternative concepts for the viaduct were also investigated and assessed.

With regard to the criterion of rail tension, rail expansion devices initially appeared to be nec-essary due to the intervals of 58,0 m between piers. These were minimized to different ex-tents in the alternatives studied below.


In Alternative 1 the number of rail expansion devices is reduced to a minimum. For aesthetic reasons, the fixed point of the bridge is designed as an A-frame. This results in bridge open-ings measuring 2 x 58 = 116 m at a predefined location next to the traffic circle on the new bypass road and in the area of the greatest height of the structure over the valley. This de-sign has already been implemented in other DB AG bridge structures, e.g. the Rombachtal viaduct, Unstruttal viaduct.

The expansion length in the direction of Prague is 7 x 58 = 406 m, whereby the rail expan-sion device behind the end of the bridge will be located on the connecting embankment. In the direction of Dresden there is an expansion length of 9 x 58 = 522 m. The joint in the su-perstructure and the rail expansion device are located above the pier in Axis 3.


In order to avoid interference with the planning for the Pirna bypass, two further bridge spans each 58 m long are added in the direction of Dresden as continuous beams. The fixed point of the bridge in the longitudinal direction is above the pier in Axis 20.

The total expansion length in the direction of Dresden is therefore 522 + 58 = 580m which is below the maximum length of 600 m specified in DB regulations.

Only two rail expansion devices are required.

Fig. 7: Alternative 1 with A-frame


Alternative 2 is based on another DB AG specification which states that the length of contin-uous beams should be limited to ca. 300 m for possible replacement at a later date. Also, it does not include the A-frame mentioned above and instead involves a bridge span 70 m long over Zehistaer Straße (road).

The entire bridge is designed as a chain of continuous beams consisting of four continuous beams with a maximum system length of 58 + 58 + 70 + 58 + 58 = 302 m. The fixed point in each system is constructed in the middle of the system by means of fixed piers. The maxi-mum expansion length is therefore 232/2 + 302/2 = 267 m.

In total, five rail expansion devices are required.

Fig. 8: Alternative 2


Variation:

As a variation on this alternative, the number of rail expansion devices can be reduced by installing longitudinal force coupling devices. However, longitudinal force coupling devices are very cost- and maintenance-intensive components and this puts the cost savings for fewer rail expansion devices into perspective. In this variation, the fixed points of the bridge are located on both abutments and the required rail expansion device is positioned in the middle of the bridge between Piers 100 and 110.


Not represented visually.

As a third alternative, a solution with constant intervals of 44 m between piers is also con-ceivable. If designed as a chain of continuous beams consisting of multiple two-span beams each spanning 2 x 44 m, the possibility of eliminating rail expansion devices is open at the current stage of planning, due to the great height of the bridge and the influence of its height on the stiffness of the foundations.

This alternative also significantly increases the number of piers, which is a great disad-vantage with respect to the landscape.

3.3.3.3.4 Assessment of alternatives

Alternative 1 Alternative 2 Alternative 3

Bridge length 1044 m 998 m 1012 m

Number of piers 16 16 22

Rail tension + - open

Construction/maintenance costs - - open

Acceptance + - -

Construction time - - -

Result + + - - -

3.3.3.3.5 Summary

With respect to the criteria of rail tension and acceptance, Alternative 1 has significant ad-vantages due to the smaller number of rail expansion devices and the design of the structure using A-frames.


In Alternative 3, the question of rail tensions/rail expansion devices cannot be answered with certainty, but there are clear disadvantages here because of the significantly larger number of piers.

With respect to construction costs and time, clear advantages are not apparent for any of the alternatives. Comparing Alternatives 1 and 2, the cost savings resulting from the smaller number of rail expansion devices in Alternative 1 are neutralized by the increased costs for constructing the A-frame. In Alternative 3, possible advantages from the elimination of rail expansion devices are neutralized by the larger number of piers.

3.3.4 Construction costs


3.3.5 Next steps in the planning process

3.3.5.1 Topography and buildings

Data on the existing topography and buildings is to be gathered on site.

Especially in the area of the Heidenau viaduct, the existing buildings must be surveyed and any resulting conflicts for the construction of the bridge structure and its subsequent mainte-nance must be identified. After this, the acceptance risks involved in the current situation must be weighed up against the costs of providing substitute measures.

3.3.5.2 Ground exploration

At the current stage of planning, no ground explorations are available in the areas surround-ing the locations of both viaducts.

In order to achieve planning and cost certainty, appropriate ground explorations must be car-ried out before the next stage of planning. Based on these, reliable foundation concepts can then be produced in cooperation with the foundation soil expert.

task 3 technical assessment of major structures...preliminary planning study new railway line...

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