wlcletch200711013 pantalla bauer&af carta · construction in 2005, machines delivery,...

FAR EAST Colenco Power Engineering AG Taefernstrasse 26 CH-5405 Baden-Daettwil

Switzerland

Telephone : +86 65068899 Mobile : Telefax : +86 65066991 E-m ail : @bauerfe.com 11/26/2007 ope-wlc

Attn : Mr Mahmoudian Homeira Telephone : +41 (0)56 483 17 58 Telefax : +41 (0)56 483 19 81

CC : E-m ail : [email protected] :

Ref. WLCLETCH200711013

Dear Mr Homeira Mahmoudian

Trench Cutter for Myanmar Project

We are pleased to provide you the information about trench cutter for Myanmar project. Please see the enclosed pages.

Best regards, BAUER BEIJING REPRESENTATIVE OFFICE

Civil Engineering Manager

SINGAPORE KUALA LUMPUR HONG KONG BEIJING TIANJIN SHANGHAI BAUER Technologies BAUER Equipment BAUER Equipment BAUER Beijing BAUER Tianjin Shanghai BAUER Far East Pte Ltd (Malaysia) Sdn Bhd Hong Kong Ltd Representative O ce Technologies Co Ltd Technologies Co. Ltd. Tel +65 6758 1977 Tel +603 7980 8334 Tel +852 2544 9613 Tel +8610 6508 8899 Tel +8622 2307 8833 Tel +8621 6959 6180 Fax +65 6753 7295 Fax +603 7981 3745 Fax +852 2545 4676 Fax +8610 6506 6991 Fax +8622 2207 8822 Fax +8621 6959 6185 [email protected] [email protected] [email protected] [email protected] [email protected] [email protected]

WLCLETCH200711013

FAR EAST

1. The low head room cutter for Yeleh project, the dimension of MBC 30 / CBC 25:

16800

Wall thickness: 640~1,500mm Max. depth: 80m Torque: 81kNm Engine: 420kW Weight: 120ton

SINGAPORE KUALA LUMPUR HONG KONG BEIJING TIANJIN SHANGHAI BAUER Technologies BAUER Equipment BAUER Equipment BAUER Beijing BAUER Tianjin Shanghai BAUER Far East Pte Ltd (Malaysia) Sdn Bhd Hong Kong Ltd Representative Office Technologies Co Ltd Technologies Co. Ltd. Tel +65 6758 1977 Tel +603 7980 8334 Tel +852 2544 9613 Tel +8610 6508 8899 Tel +8622 2307 8833 Tel +8621 6959 6180 Fax +65 6753 7295 Fax +603 7981 3745 Fax +852 2545 4676 Fax +8610 6506 6991 Fax +8622 2207 8822 Fax +8621 6959 6185 [email protected] [email protected] [email protected] [email protected] [email protected] [email protected]

WLCLETCH200711013

FAR EAST

8400

6000

1200 2000 4000 1200 Ventilation pipe

Electric cables

910

CL

Concreting pipes, Slurry pipes

COW (T=1000mm)

Working space inside the tunnel of Yeleh COW Project


WLCLETCH200711013

FAR EAST

2. Trench cutter at Tamanthi H.E. Project of Myanmar Bauer has delivered 2 units trench cutter BC 32 / HTS 70m to Myanmar Tamanthi H.E. Project at 2006. Machines belong to Irrigation department and Hydropower department of Myanmar government. Machine rigged up at March 2006, and the test cell construction have been executed by trench cutter at November 2006 to February 2007. The dimension of BC 32 / HTS 70:

Wall thickness: 640~1500mm Max. depth: 70m Torque: 81kNm Engine: 478kW Weight: 163ton


WLCLETCH200711013

FAR E AST

BC 32 / HTS 70 at Tamanthi H.E. Project

The net cutting performance in the weathered rock, it depends on the type of rock, the roughly �gure: Compressive strength 5 ~ 30MPa: 8~20 m3/hr (Standard cutter wheel) Compressive strength 30 ~ 60MPa: 4~10 m3/hr (Standard cutter wheel) Compressive strength 60 ~ 90MPa: 2~5 m3/hr (Round shank chisel cutter wheel)

The running cost of trench cutter is about Euro/month, all manpower and auxiliary equipment exclusive. Bauer Far East has been provided the method statement for cut-o� wall construction in 2005, machines delivery, commissioning, training and test cell planning and operation with Myanmar operation crews. We have met two gentlemen from Colenco company at Tamanthi project several times, you may contact them for more information about cut-o� wall at Tamanthi. Mr. Karl Steiger [email protected] Mr. Voborny Ondrey

SINGAPORE KUALA LUMPUR HONG KONG BEIJING TIANJIN SHANGHAI BAUER Technologies BAUER Equipment BAUER Equipment BAUER Beijing BAUER Tianjin Shanghai BAUER Far East Pte Ltd (Malaysia) Sdn Bhd Hong Kong Ltd Representative O�ce Technologies Co Ltd Technologies Co. Ltd. Tel +65 6758 1977 Tel +603 7980 8334 Tel +852 2544 9613 Tel +8610 6508 8899 Tel +8622 2307 8833 Tel +8621 6959 6180 Fax +65 6753 7295 Fax +603 7981 3745 Fax +852 2545 4676 Fax +8610 6506 6991 Fax +8622 2207 8822 Fax +8621 6959 6185 [email protected] [email protected] [email protected] [email protected] [email protected] [email protected]

WLCLETCH200711013

mailto:[email protected]

Comprehensive Proposal for

Construction of Cut-Off Wall at Tazon Site

Tamanthi Hydroelectric Project, Myanmar

Submitted by Bauer Technologies Far East

February 2006

Bauer Trench Cutter BC 32 Construction of Cut-Off Wall for Tamanthi Project, Myanmar February 2006

2 BAUER EQUIPMENT SINGAPORE KUALA LUMPUR HONG KONG TAIPEI BEIJING TIANJIN FAR EAST TEL: 6756-8033 TEL: (03) 780-8334 TEL: 2544-9613 TEL: (02) 8732-6455 TEL: (010) 6506-8899 TEL: (022) 2621-5178

LIST OF CONTENTS

1. General…………………………………………………………………………….. 3

2. Dimensions and Quantities………………………………………………………. 3

3. Soil Condition……………………………………………………………………… 4

4. Method Statement………………………………………………………………… 5

4.1 Sequence of Work………………………………………………………………… 5

4.2 Platform and Guide Wall Preparation..…………………………………………. 6

4.3 Excavation Process of Cut-Off Wall and Overlap Cutter Joint………………… 7 4.3.1 Cutting Process of Bauer BC 32….……………………………………...10

4.3.2 Panel Excavation………………………………………………………... 12 4.3.3 Recycling……………………………………………………………….... 14 4.3.4 Trenching Sequence………………………………………………….… 17

4.4 Panel Layout………………………………………………………………………… 18

4.5 Concreting…………………………………………………………………………... 18

4.6 Recommended Equipment and Manpower.……………..………………………...20

5. Basic Data for Estimate……………………………………………………………. 22

5.1 Performance Data………………………………………………………………….. 22

5.2 Production Rate…………………………………………………………………….. 22

6. Cut-Off Wall Plastic Concrete Mix…………………………………………………. 23

7. Estimation on Diesel and Bentonite Consumption………………………………. 23

8. Required Material for First Starting……………………………………………… 23

9. Safety Equipment………………………………………………………………….. 24

Appendix A – Preliminary Schedule of Cut-Off Wall Construction…………….…….. 25

Appendix B – Plastic Concrete Mixing Design and Testing …………………………. 27

Appendix C – Further Soil Investigation ……………………………………………….. 31

FAX: 6753-7295 FAX: (03) 781-3745 FAX: 2545-4676 FAX: (02) 8732-6453 FAX: (010) 6506-6991 FAX: (022) 2621-3575



1. General It is required to construct Cut-Off Wall (COW) for the Tamanthi Hydroelectric project in Myanmar. This proposal describes the method to construct COW with the BAUER trench cutter BC 32.

2. Dimensions and Quantities

Overall Cut-Off Wall length 2,351 m (7,759 ft)

Wall depth Average 50 m (Max. 70 m)

Wall thickness 1.0 m

Estimated wall area 117,550 m2

Estimated volume of wall 117,550 m3

The following information provides a basis of the method by which the works will be carried out using Bauer equipment, but may have to be modified as required based on actual site conditions.




3. Soil Condition Based on the received 3nos of soil investigation on Colenco dam axis. (final dam axis has not confirmed yet), it can be summarized in a general profile. (Figure1.1)

GL 0.0m

Layer 1 Clay SPT N = 9 ~ 16

GL –15.0m

Layer 2 Sand with Gravel SPT N = 10 ~ 50* (assumed) (Actual SPT N value up to 21m only)

GL –38.0m

Layer 3 Mudstone qu = 5 ~ 15MPa (assumed)

GL -50.0mLayer 4

Weathered Sandstone qu = 10 ~ 20MPa (assumed)

GL –58.0mLayer 5

Sandstone qu = 20 ~ 40MPa (assumed)

GL -60.0m

Figure 1.1 Soil condition




4. Method Statement

4.1 Sequence of Work

COMMENCEMENT

SURVEY

CONFIRMATION

SURFACING

MOBILIZATION

TESTING

CHECKING

CAGE

EXCAVATION

REINFORCEMENTCAGE

INTO POSITION

TREMIE PIPE

CONCRETINGCONCRETING

WORK DONE

CONCRETINGSTABILZER

EXCAVATION

WORK DONE DISPOSAL

SPOILS

SURVEY REVIEW

COMMENCEMENT

PLANNING

APP. POWER/ WATER

BAR BENDING

PEINFORCEMENTREINFORCEMENTWORKSHOP

MOBILIZATION

BENTONITE MIXTURE

SLURRY TREATMENT

FLOW CHART

RECOVERY OF

TREATMENT PLANTSET UP OF SLURRY

Subject to design requirement




4.2 Platform and Guidewall Preparation

Due to the operation weight of one unit of trench cutter is about 120ton, appr. 2m deep x 12m wide compacted working platform on upper stream side is recommend to provide enough bearing capacity and space for such heavy equipment. See figure 4.1. Local gravel and sand mixture can be used as the filling material of platform. It should be compacted by heavy duty compacting roller every 300mm layer. As site layout, we recommend the trench cutter should be working on the upper stream side of G/W, and all the other equipment / material should be supplied from down stream side (such like concrete truck, service crane,...etc.). 6m wide working platform on down stream side is recommended. Figure 4.1 Working Platform The underground obstruction shall be removed and backfill with stabilized material prior to the construction of guide wall. A reinforced concrete guide wall shall be constructed according to the design and dimensions as stated in the specifications and relevant drawings. The firm working platform is necessary in providing enough bearing capacity for those heavy equipment, e.g. BC 32 on base machine Liebherr HS 885, with operation weight up to 120 tons. (See Figure 4.2 and 4.2)

250 X+50 250

1500

2 50

1 00

700 X+50 700

D16 each 250mm

Bracing each 2mBracing each 2m

2

Blinding concrete

210kg/cm concrete

Backfilled & compactedor lean concrete

Figure 4.2 Typical Guide Wall Structure




The pre-cast guide wall can also be used to speed up the platform construction. Each section of pre-cast guide wall should be 4~6m with proper steel formwork. The construction method is similar to cast-in-situ guide wall system.

Figure 4.3 Guide Wall Cast in Situ

4.3 Excavation Process of Cut-Off Wall (COW) Using Overlap Cutter Joint Overlap Cutter Joint (OCJ) is the advantage when using trench cutter for diaphragm wall excavation, it is adopted in this project to provide water tight joint system. For construction of diaphragm wall and/or cut-off wall with OCJ requires the formation of primary panel alternatively located 2.2~2.6m apart prior to over cutting of secondary panels. The construction of secondary panel normally needs some 0.1m~0.3m (depending on soil condition and COW depth) over cutting into each adjacent casted primary panels forming a water resistant concrete joint about 2.8m apart. The diaphragm wall excavation technique with recommended panel joint, overlap cutter joint, is shown in Figures 4.4 & 4.5.

Figure 4.4 Over-Cut Joint




Figure 4.5 Typical Construction Sequence with Over-Cut Joint




Table 4.1 Project Reference of Over-Cut Joint System with Bauer Trench Cutter

Item Time Projet / Country Thickness (mm) Max. Depth (m) Area (m2) 1 1984 Interchange 19 Abu Dhabi, U.A.E. 1000 23 27500 2 1986 Comm. & Resid. Center, Jeddah Saudi

Arabia 600 25 3000

3 1986 Diwan Underpass, Jeddah Saudi Arbia 600 & 1000 27 26400 4 1986 Hazama Shafts C11, Jeddah Saudi Arbia 600 32 5000 5 1986 Jeddah Commercial Center, Saudi Arbia 600 20 5000 6 1987 Bisha Dam, Bisha Saudi Arbia 1000 30 12000 7 1987 Conwy Cutoff Walls, Conwy U.K. 600 25 1600 8 1987 National History Museum, Viena Austria 800 27 4200 9 1987 Parking Estienne, Marseille France 500 18 8470 10 1987 Gare de Paris II, Paris France 500 & 600 30 8000 11 1987 Armed Forces Officers Club, U.A.E. 800 23 10000 12 1987 Gare de Paris I, Paris France 600 30 2800 13 1988 The Galleries Broadmead, Bristol U.K. 800 19 7400 14 1988 Shwaib Dam, Al Shwaib U.A.E. 600 10 19000 15 1989 Misato Sewage Plant, Tokyo Japan 1200 49 4797 16 1989 Metropolitan Highway, Tokyo Japan 800 75 2229 17 1989 Chiba Sewage Pump House, Tokyo Japan 1000 42 6003 18 1989 Redhill Retail Center, Redhill U.K. 800 21 9500 19 1990 Wister Dam, Oklahoma U.S.A. 600 21 19050 20 1991 Hotel Corso, Vienna Austria 800 31 9500 21 1991 Metro Madrid Spain 1000 30 8000 22 1991 Fleischmarkt Postparkasse, Vienna Austria 600 9 5050 23 1991 Telecom Center, Singapore 800 32 8900 24 1991 Pacific Plaza, Singapore 800 & 1000 48 5800 25 1991 Kamtneerringhof, Vienna Austria 600 & 800 34 7000 26 1991 Boulevard Laveran, Marseille France 600 9 5050 27 1992 ADGAS Third LNG Project, DAS island U.A.E 600 23 4200 28 1992 Inland Revenue Department, Singapore 1000 48 10200 29 1992 Clock Tower Underpass, Dubai U.A.E. 600 19 6300 30 1993 Meeks Cabin Dam, Wyoming U.S.A. 900 51 11500 31 1994 Peruca Dam, Peruca Croatia 1000 50 9000 32 1995 Alex. Central Zone, Alexandria Egypt 800 23 4700 33 1995 Extension of Safir Hotel, Cairo Egypt 800 16 1071 34 1995 Opera Residential Building, Cairo Egypt 800 19 1050 35 1995 Al-Akhbar Building, Cairo Egypt 600 19 1120 36 1995 Manege Square Moscow, Moscow Russia 900 41 5000 37 1995 Mira Prospect Moscow, Moscow Russia 900 35 3800 38 1995 Annex Building, Seoul Korea 1000 37 12950 39 1996 Eastside Dam Reservoir, Calfornia U.S.A. 900 41 15650 40 1996 New Dong-A CE Building, Seoul Korea 1000 38 7845 41 1996 Kyung Nam Building, Seoul Korea 1000 35 7111 42 1996 Sam Ho Garden Plaza, Seoul Korea 800 26 4498 43 1996 Lotte Ddepartment, Kwang Ju City, Korea 1000 43 15179 44 1996 Kwang Myung Subway, K.M. City, Korea 640 17 18700 45 1996 H6 Gilman Plaza, Hong Kong 1200 55 16000 46 1998 Park City, Moscow Russia 900 24 22000 47 2001 Diavik, Canada 1000 30 42000 48 2001 Kwun Tong Commercial Building, H.K. 1200 44 5500 49 2001 LNG Tanks, Korea 1500/1700/1900 71~88 112400 50 2001 MRT 504 Changi Airport Station 800 50 17000 51 2001 Changi Water Reclamation Plant C2A 1200 68.5~72.5 25462 52 2002 Dhauliganga COW, India 1000 75 7870




53 2002 Kowloon Station Package 7, Hong Kong 1500 85~95 21912 54 2004 Yeleh Hydro Dam Project, China 1000 60~75 13033 55 2004 Wang Tang Power Plant, China 800/1200 35 18092 56 2005 Hungpu Nancha Bridge, China 1200 35~40 8356

4.3.1 Cutting Process of Bauer BC 32

The Bauer BC 32 are the excavation equipment, which loosens the ground with its teeth, embedded in the cutting wheels and mixes it with bentonite suspension.

If required, the soil can be broken down to a fragment size of 70-80 mm or less. The centrifugal pump in the BC 32 has been designed to pump fragments of this size together with the suspension out of the trench (see figures 4.5 & 4.6)

Figure 4.5

Figure 4.6

The centrifugal pump of the BC 32 located immediately above the cutter wheels con-tinuously removes all of the spoil and soil bentonite suspension to the Slurry Treatment Plant.

The Slurry Treatment Plant which consists of two Desanders BE 250 and one Prescreener GS 500 separates the soil and spoil from the Slurry.

The Feedpump, which is, located at the Slurry Treatment Plant pumps the regenerated Slurry back to the trench hence achieving a closed circuit.



BAUER EQUIPMENTFAR EAST

To crush bigger stones or rock fragments into pieces small enough to pass through the pump inlet special devices with a dynamic effect are necessary. Elastic shock absorbers built into the cutter drums protect the gearbox against damage (see Figure 4.7).

Figure 3.6

S

hock absorber Ejector plates Suction box Flipper tooth Flipper tooth

11 SINGAPORE KUALA LUMPUR HONG KONG TAIPEI BEIJING TIANJIN

TEL: 6756-8033 TEL: (03) 780-8334 TEL: 2544-9613 TEL: (02) 8732-6455 TEL: (010) 6506-8899 TEL: (022) 2621-5178

Figure 4.7

To cut the ridge being left between the cutting wheels at the bottom of the trench so-called tip-aside teeth is installed on the cutting wheels. This special teeth tilts every time it reaches the bottom of the trench by means of a mechanical guide device.

The performance of BC 32 are crucially dependent upon its power potential characterized by the crowd force (BC 32 weight = 25 ~ 32 ton) and the torque (= 2 x 81 kNm) of the cutting wheels. Both power components mutually influence each other (see figure 4.8)

Figure 4.8 The BC 32 are not only equipped with strong power reserves, but is also reaching an optimum output by controlling H and V in an extremely sensitive way.




4.3.2 Panel Excavation

The trench cutter is a reverse circulation excavation tool, which loosens the ground with its teeth embedded cutting wheels. The spoil is then removed form the panel by a suction pump and transported in the bentonite suspension via pipe network to the desanding plant, where it is separated form the bentonite by vibrating screens and cyclones. Please refer to Figure 4.10.

The bentonite is then pumped back to the trench hence achieving a closed circuit. The spoil is collected in basins located beneath the shakers. These basins are emptied by excavator periodically as required.

The verticality of the trench cutter will be measured in the panel axis and perpendicular to the panel axis by means of two independent inclinometers. The data provided by these instruments will be processed by the on-board computer and displayed so that the operator can continuously monitor and if necessary correct the verticality of the cutter. Adjustment of the verticality in the panel axis can be achieved for example by varying the cutter wheel speed.

In case, when the strength of rock or boulder exceed 60 MPa, Round Shank Chisel (RSC) cutting wheel or Roller Bits cutting wheel are recommended for the hard rock excavation. (see Figure 4.9)

Figure 4.9 RSC wheel (left), Roller Bits wheel (right)



BAUER EQUIPMENT SINGAPORE KUALA LUMPURFAR EAST TEL: 6756-8033 TEL: (03) 780-833

CUTTTING CONCRETING

SCALPING UNIT

DESANDER

DECANTER

> 5 mm

> 0.06 mm

> 0.01 mm

WORKING BENTONITE TANKS

CONCRETING BENTONITE TANKS

BENTONITE MIXING

FRESH BENTONITE TANK

Specification of submersible pump for concreting: Lift: 5m Pumping distance: 300m Power: 20HP Capacity: 100m3/hr

Use booster pump See Figure 4.13

(OPTIONAL)

FAX: 6753-7295 FAX: (03) 781-374

Figure 4.10

13 HONG KONG TAIPEI BEIJING TIANJIN

4 TEL: 2544-9613 TEL: (02) 8732-6455 TEL: (010) 6506-8899 TEL: (022) 2621-5178

5 FAX: 2545-4676 FAX: (02) 8732-6453 FAX: (010) 6506-6991 FAX: (022) 2621-3575



4.3.3 Recycling Following the completion of panel excavation the used bentonite will be circulated, partly exchanged or completely replaced by fresh bentonite as is required to achieve the necessary properties prior to concreting. The decision whether to replace or circulate will be taken according to the condition of the used slurry.

Desanding will be carried out either by suspending a submersible pump in the trench or by using the trench cutter. The recommended site layout, which includes slurry plant, steel yard, pipelines arrangment for 3 construction phases are shown on Figures 4.11 to 4.13.

Figure 4.11 Slurry Treatment System

DECANTER

DESANDER

BENTONITE TANK

Optional

Figure 4.12 Bauer Desander BE 500



BAFA

Bentonite Batching Plant

With all single bite panels arrangement, the maximum excavation volume (slurry volume) for one panel is about 196cbm. Recommend slurry plant arrangement see figure 3.12. (the capacity of slurry tank has to be increased up to at least 500cbm for fresh bentonite, and 700cbm for working bentonite, in case of 3 bites large primary panel be performed.) The top of the slurry pit should be higher than the highest flooding level minimum 500mm.

555555666666

5.0

m5.

0 m

5.0

m

BBBBBB

SSS333333

444444222222111111

777777

888888

Booster Pump and Pump BasinBooster Pump and Pump BasinBooster Pump and Pump Basin4.5 m4.5 m4.5 m4.5 m4.5 m4.5 m5" Pipeline System

A: Return Line from CutterB: Supply Line for ExcavatingC: Return Line for ConcretingD: Spare Line

6" Pipeline System


5" Pipeline System


6" Pipeline System


5" Pipeline System


6" Pipeline System


DDDDDD

BBBBBBAAAAAA

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5.0

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11

33

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22

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4.5 m4.5 m

BBBooster Pump and Pump Basin

S

DD

BBAA

CC

5" Pipeline System


6" Pipeline System


5566

5.0

m

11

33

4422

77

88

4.5 m4.5 m

BB

6 1 25

7

3

4

8

DCBA

4.5 m

B

5" Pipeline System


6" Pipeline System


8

D

BA

C 7

56

5.0

m 3

14

2

4.5 m

BBooster Pump and Pump Basin

S

Booster Pump and Pump Basin5" Pipeline System


6" Pipeline System


DD

BBAA

CC

for waste bentonite

UER EQUIPMENT SINGAPORE KUALA LUMPUR HONG KONG TAIPEI BEIJING R EAST TEL: 6756-8033 TEL: (03) 780-8334 TEL: 2544-9613 TEL: (02) 8732-6455 TEL: (010) 65

Dia. 13mm @Dia. 13mm @Dia. 13mm @Dia. 13mm @Dia. 13mm @Dia. 13mm @

250mm Tfc

250mm Tfc

250mm Tfc

250mm Tfc

250mm Tfc

250mm Tfc

10.010.010.0

FRESH (CONCRBENTONITE BASEFFECTIVE VOL



3.6

m

0.5

m

3.6

m

0.5

m

3.6

m

0.5

m

3.6

m

0.5

m

3.6

m

0.5

m

3.6

m

0.5

m

CROSS SECTION B-BCROSS SECTION B-BCROSS SECTION B-BCROSS SECTION B-BCROSS SECTION B-BCROSS SECTION B-B Dia. 400mm Pipe and ValveDia. 400mm Pipe and ValveDia. 400mm Pipe and ValveDia. 400mm Pipe and ValveDia. 400mm Pipe and ValveDia. 400mm Pipe and Valve TYPICALTYPICALTYPICALTYPICALTYPICALTYPICAL

10.5 m14.75 m

WORKINGBENTONITE BASINEFFECTIVE VOL.: 400 cbm

14.75 m10.5 m


Highest Flooding Level


10.5 m14.75 m

25cm Thickness R.C. Wall and Slab25cm Thickness R.C. Wall and Slab25cm Thickness R.C. Wall and Slab25cm Thickness R.C. Wall and Slab25cm Thickness R.C. Wall and Slab25cm Thickness R.C. Wall and Slab

2.2

m2.

2 m

2.2

m

4.40

m

1.2

m1.

2 m

4.40

m4.

40 m

4.40

m

1.2

m1.

2 m

4.40

m

1.2

m1.

2 m

4.40

m

3.20

m3.

20 m

3.20

m3.

20 m

3.20

m3.

20 m

CROSS SECTION A-ACROSS SECTION A-ACROSS SECTION A-ACROSS SECTION A-ACROSS SECTION A-ACROSS SECTION A-A

2.0

m2.

0 m

2.0

m2.

0 m

2.0

m2.

0 m

GROUND LEVEL

Booster Pump BasinBooster Pump Basin

GROUND LEVELGROUND LEVELGROUND LEVEL


GROUND LEVELGROUND LEVEL


PRE-SETTLEMENTAREAPRE-SETTLEMENTAREAPRE-SETTLEMENTAREAPRE-SETTLEMENTAREAPRE-SETTLEMENTAREAPRE-SETTLEMENTAREA

5.0 m5.0 m5.0 m5.0 m5.0 m5.0 m

GROUND LEVELGROUND LEVELGROUND LEVELGROUND LEVELGROUND LEVELGROUND LEVEL

Spoil Material PitSpoil Material PitSpoil Material PitSpoil Material PitSpoil Material PitSpoil Material Pit

BE 500BE 500BE 500BE 500BE 500BE 500

500

3.5 m3.5 m3.5 m3.5 m3.5 m3.5 m2.7 m2.7 m2.7 m2.7 m2.7 m2.7 m

BE 500BE 500BE 500BE 500BE 500BE 500 Platform BBBBBB

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500

Highest Flooding Level

3.6

m

0.5

m

3.6

m

0.5

m

TYPICALTYPICALCROSS SECTION B-BCROSS SECTION B-B Dia. 400mm Pipe and ValveDia. 400mm Pipe and Valve


250mm Tfc

250mm Tfc

Dia. 13mm @Dia. 13mm @

10.0


CROSS SECTION A-ACROSS SECTION A-A

2.2

m

PRE-SETTLEMENTAREAPRE-SETTLEMENTAREA



4.40

m

1.2

m1.

2 m

4.40

m

3.20

m3.

20 m

2.0

m2.

0 m

25cm Thickness R.C. Wall and Slab25cm Thickness R.C. Wall and Slab

Platform

10.5 m14.75 m

BE 500BE 500

2.7 m2.7 m5.0 m5.0 m

Spoil Material PitSpoil Material Pit

3.5 m3.5 m

BE 500BE 500 BB

WORKINGBENTONITE BASINEFFECTIVE VOL.: 400 cbmAA

3.5 m2.7 m5.0 m

A

B

GROUND LEVEL

3.6

m

GROUND LEVEL

4.40

m

1.2

m

3.20

m

CROSS SECTION A-A

CROSS SECTION B-B


BE 500Spoil Material Pit

2.0

m0.

5 m

PRE-SETTLEMENTAREA

BE 500

Dia. 400mm Pipe and Valve

Booster Pump Basin

25cm Thickness R.C. Wall and Slab

Dia. 13mm @

250mm Tfc

TYPICAL

3.6

m

0.5

m

CROSS SECTION B-B Dia. 400mm Pipe and Valve TYPICAL

25cm Thickness R.C. Wall and Slab

10.05.0 m

1.2

m

4.40

m

3.20

m

CROSS SECTION A-A

GROUND LEVEL

2.2

m

Spoil Material Pit

Booster Pump Basin

GROUND LEVEL

PRE-SETTLEMENTAREA

2.0

m

10.5 m14.75 m

BE 500

2.7 m3.5 m

BE 500 B

A


Dia. 13mm @

250mm Tfc

3.6

m

0.5

m

3.6

m

0.5

m

TYPICALTYPICALCROSS SECTION B-BCROSS SECTION B-B Dia. 400mm Pipe and ValveDia. 400mm Pipe and Valve

10.0

BE 500BE 500

3.5 m3.5 m14.75 m

2.2

m

4.40

m

3.20

m

CROSS SECTION A-A

4.40

m

3.20

m

CROSS SECTION A-A

1.2

m1.

2 m

2.0

m2.

0 m

Spoil Material PitSpoil Material Pit


5.0 m5.0 m 2.7 m2.7 m

BE 500BE 500

25cm Thickness R.C. Wall and Slab25cm Thickness R.C. Wall and Slab



PRE-SETTLEMENTAREAPRE-SETTLEMENTAREA

Dia. 13mm @Dia. 13mm @

250mm Tfc

250mm Tfc

10.5 m

BB

AA

Figure 4.13 Typical Slurry Plant

FAX: 6753-7295 FAX: (03) 781-3745 FAX: 2545-4676 FAX: (02) 8732-6453 FAX: (010) 65

poil Pitpoil Pitpoil Pitpoil Pitpoil Pitpoil Pit

15 TIANJIN

06-8899 TEL: (022) 2621-5178

8.5

m8.

5 m

8.5

m8.

5 m

8.5

m8.

5 m

4.4

m

3.2

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1.2

m1.

2 m

3.2

m

4.4

m4.

4 m

3.2

m

1.2

m1.

2 m

3.2

m

4.4

m4.

4 m

3.2

m

1.2

m1.

2 m

3.2

m

4.4

m

200mm 200mm 200mm 200mm 200mm 200mm

hickness R.C.' = 210 kg/cmhickness R.C.' = 210 kg/cmhickness R.C.' = 210 kg/cmhickness R.C.' = 210 kg/cmhickness R.C.' = 210 kg/cmhickness R.C.' = 210 kg/cm

m m m

BentoniteMixerBentoniteMixerBentoniteMixerBentoniteMixerBentoniteMixerBentoniteMixer

ETING)IN

.: 250 cbm

ETING)IN

.: 250 cbm

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.: 250 cbm AAAAAA

R.C. STRUCTURE R.C. STRUCTURE R.C. STRUCTURE R.C. STRUCTURE R.C. STRUCTURE R.C. STRUCTURE

ETING)IN

.: 250 cbm 8.5

m8.

5 m

4.4

m

3.2

m

1.2

m1.

2 m

3.2

m

4.4

m

AA

R.C. STRUCTURE R.C. STRUCTURE

ETING)IN

.: 250 cbm

hickness R.C.' = 210 kg/cmhickness R.C.' = 210 kg/cm

200mm 200mm

m

8.5

m8.

5 m

4.4

m

3.2

m

1.2

m1.

2 m

3.2

m

4.4

m

BentoniteMixerBentoniteMixer

AA 8.5

m

A

4.4

m

3.2

m

1.2

m

ETING)IN

.: 250 cbm

BentoniteMixer

200mm

hickness R.C.' = 210 kg/cm


m

8.5

m1.

2 m

3.2

m

4.4

m

200mm

hickness R.C.' = 210 kg/cm

BentoniteMixer

A


m

BentoniteMixerBentoniteMixer

200mm 200mm

hickness R.C.' = 210 kg/cmhickness R.C.' = 210 kg/cm

06-6991 FAX: (022) 2621-3575



Slurry operation with pipeline design as figure 4.13:

Site activities Valve Open

Valve Close

Remark

Excavation 1, 3, 5 2, 4 Supply working bentonite to trench via pipeline B, bentonite with excavated material pump to BE 500 via pipeline A

Desanding 2, 3, 5 1, 6 Supply fresh bentonite to trench via pipeline B, working bentonite pump back to BE 500 via pipeline A

Concreting 7 8 Fresh (concreting) bentonite pump back from trench to fresh bentonite basin with pipeline C

Contaminated bentonite

8 7 During panel concreting, the last 3~5 meter bentonite which contaminated by plastic concrete has to be abandoned.

Location of Slurry Plant of First Stage

Based on the capacity of mud pump on BC 32 and booster pump KBKT, the suitable working distance between BC 32 and slurry plant is within 300m. The slurry plant should be located on the downstream side of working platform. Excavator or wheel loader with dump truck has to remove the spoil material when it’s necessary. The area to be completed first shall be the area of the intended river diversion according to PROJECT CONSULTANT’s decision.

As the site situation, COW for the area for river diversion should be completed at first. And the recommended location of slurry plant see figure 3.15.

300m

300m

First stage COW area

Slurry Plant

Figure 4.14 First Stage COW Area and Slurry Plant Location




4.3.4 Trenching Sequence:

There are certain empirical rules to be considered for a trouble free cutting sequence with trench cutters.

The Cutter should always work within similar boundaries as far as possible. The sketches below illustrate typical applications.

• Soil - Soil cutting

• Concrete - concrete cutting

• Slurry - Slurry

• Artificial guidance - soil or concrete

(This is also applicable for cutting at water stop beam)

Figure 4.15 Typical cutting methods




4.4 Panel layout Two types of panels are applicable when working with the Bauer BC 32:

• Primary panels

• Secondary panels (for closing the wall)

Since cutter have an equipment length of 2.8 m, the excavated length of a primary panel shall be either 2.8 m or a variable length between 6.4 m and 7.0 m. Based on these modules of panel length a shop drawing will be prepared prior to starting the works and submitted for approval.

Since Cutter technologies & Cutter Overlap Joint will be the first time used in Myanmar and consider the maximum COW depth 70m, we recommend to use one cut 2800 mm one panel as simple and smooth operation for Tamanthi project. Please refer to the proposed panel layout shown in Figure 4.16.

Figure 4.16 Proposed Panel Layout with Overlap Cutter Joint

Based on above there are total approximate 940 panels (wall length 2,351 m) and 470 each for primary and secondary. Overcut may be reduced for short panel base on site trial.

4.5 Concreting Concrete (Plastic Concrete with strength 1~2 MPa recommended) will be supplied to site in

ready-mix trucks at a rate sufficient to ensure at least 15 m3/hour per tremie. The number of

tremie pipes will be determined primarily by the length of the panel to be concreted. For panels up to 3-m long one tremie, for longer panels two tremie pipes will be used. Before the commencement of each pour a sacrificial buffer between bentonite and concrete will be placed in each tremie to hinder mixing and concrete segregation. This buffer may take the form of a plastic bag filled with rags or a rubber ball.

For the case of two or three tremie pipes, tow or three trucks respectively will be required to start the pour to ensure that no bentonite is trapped by concrete at the bottom of a panel. During




concreting the tremie pipes will be kept continuously immersed in the fresh concrete by a minimum of 3 meters. For multiple tremie pours the level of the concrete in each tremie will be regularly checked in order to ensure that the difference in level is limited in order to avoid bentonite inclusions in the finished wall.

The bentonite displaced during concreting will be pumped to storage tanks. However, the last approx. 2 m depth of bentonite in the panel, i.e. the bentonite in contact with the fresh concrete will be wasted.

Lifting Cap Support Fork

O-Ring

Seil Rope

Pipe Coupling with Steel Cable (Standard)

Pipe Connection with Threads (Option)Starter Pipe

Tremie Pipe

Hopper

Tremie Pipe

Starter Pipe

Hopper

Seil Rope


O-Ring

Pipe Connection with Threads (Option)

Support ForkLifting Cap

Tremie Pipe

Starter Pipe

Hopper

Seil Rope


O-Ring



Tremie Pipe

Starter Pipe

Hopper

Seil Rope


O-Ring



Figure 4.17 Tremie Pipe System

Plastic Concrete Batching Plant The recommend location of concrete batching plant see figure 4.18, nearby the fuel tank area. The level of batching plant platform should not be lower than fuel tank area.




First stage COW

Plastic concrete batching plant

Figure 4.18 Recommend location of plastic concrete batching plant

According to the capacity of Stetter M 1 concrete mixer is 56 m3/hr and cycle time estimation of mixing truck (table 5.2), at least 6 Nos. of mixing truck (capacity 5m3) are necessary for operation.

Table 4.2 Cycle time estimation of mixing truck:

Activities Time

Fill up mixing truck 5 mins

Transport to trench 10 mins

Discharge to the trench 10 mins

Return to batching plant 10 mins

Total 35 mins

Sufficient water supply to mixer is strongly recommended to keep high mixing performance. If necessary, water tank is recommended to store water beside mixer. The suitable capacity of water tank is appr. 80cbm (water quantity for 1 single bite panel concrete)

4.6 Recommended Main Equipment and Manpower

Main Equipment Item Description Nos. Remarks Supply

1 Bauer BC 32 on HS 885 Max. cutting depth 70 m

2 Standard cutter wheel 1000 mm Bauer

2 Bauer Desander BE 500 2 For Cutter BC 32 Bauer 3 Bentonite Mixer 2 Bauer 4 KBKT Feed Pump 2 For Slurry Supply Bauer




5 Submersible Pumps 4 For Bentonite return during concretingy Customer7 Auxiliary Pumps (optional) 4 For bentonite handling at bentonite plant Customer8 Slurry Supply

6” Flange Piping 2000 m For Slurry Handling (c/w ball valves, elbows,

T-joints) Customer

9 Slurry Return 6” Flange Piping

2000 m For Slurry Handling (c/w ball valves, elbows, T-joints)

Customer

10 Concreting Slurry 4” Flange Piping

2000 m For Slurry Handling (c/w ball valves, elbows, T-joints)

Customer

11 Backhoe or wheel loader 2 Customer12 50 ~ 80 ton Crawler Crane 2 Service crane Customer13 Generator 600 KVA 2 For Slurry Handling Equipment Customer14 Generator 400 KVA 2 For Plastic Concrete Batching Plant Customer15 Tremie Pipe 84 m 2 sets Diameter 244 mm (with hopper & wires) Bauer 16 Night Working Lights 12 sets Subject to actual site condition Customer17 Welding machine 300 Amp 4 sets One for Cutter hard facing Customer18 Survey Instrument 2 sets Customer19 Slurry Testing Device 2 sets Customer20 Water Jet Gun 2 sets For Cleaning of Job Site & Cutter Customer21 Concrete Mixer Truck 6 For Concrete Supply 5 to 8 m3 per truck Customer22 Concrete Bentonite Basin 2 For Bentonite Handling Customer23 Bentonite Silo 10 ton 2 For Bentonite Storage Customer24 Steel Beam 2 set For supporting the Desanding Plant Customer25 Steelplates 2m x 5m x

25mm 40 For Ground Platform Customer

26 Storage Container 2 For Spare and Wear Parts Storage Customer27 Water tank (30cbm) 3 For concrete plant and desanding plant Customer28 Trailer truck (30ton) 1 For site transportation Customer29 Dump truck 6 For spoil soil removal Customer

Manpower, Assume double shift (12 hrs/shift) per Day Item Designation Nos. Remarks

1 Project Manager 1 2 Site Engineer 4 3 Site Foreman 4 4 Accountant 1 5 BC Operator 4 6 Backhoe Operator 4 7 Mechanic 2 8 Electrician 2 9 Welder 4 Two for cutter

10 Batching Plant Forman 2 11 Batching Plant Labor 4 One per shift 12 Common Labor 20 One for each cutter per shift 13 Crane operator 4 14 Total approx. 56

Note: Guide wall, R.C. pavement and steel cage fabrication (if required) by subcontractor.




5. Basic Data for Estimate 5.1 The performance data:

Strata Depth Soil Condition Output Rate

1 GL -3.0m ~ -15.0m* See Figure 8.1 10~15 m3/hr (by Cutter BC 32)

2 GL -15.0m ~ -38.0m See Figure 8.1 20~25 m3/hr (by Cutter BC 32)


4 GL –50.0m ~ -58.0m See Figure 8.1 15~20 m3/hr (by Cutter BC 32)


*G.L. +0.0 ~ -3.0m top 3m pre-excavated by excavator.

The performance is strictly based on the soil conditions and where not available in enough details the assumptions made by Bauer. If the soil conditions differ from ones in this Method Statement other performance value may be applicable. The production rates are gross values. Efficiency factors should be added to these values. The values are estimated figures based on past project experience. They are tabulated without liability.

5.2 The production rate:

Positioning & Pipes Connection 1.0 hrs

Layer 1 (2.8m x 1.0m x 12.0m) / (10~15 m3/hr)= 2.2 ~ 3.4 hrs





Total hours for one cut (instant output) 9.0 ~ 11.9 hrs

Net Cutting Performace

(2.8m x 1.0m x 60.0m) / (9.0 ~ 11.9 hrs)

14.12 ~ 18.67 m3/hr

Average performance:

(2.8m x 1.0m x 50.0m) / (9.0 ~ 11.9 hrs) x 0.75 x 0.8 =

7.06 ~ 9.33 m3/hr Efficiency factor to be 0.75 “Equipment related” which allows for outside influence, like maintenance, repairs and the other factor 0.8 “Operation related” is for site organization, working shift arrangement, heavy rains, late start, etc be confirmed by contractor.




The estimated wall volume is 117,550 m3 in total.

(117,550 m3) /(9.33~7.06 m3/hr)= 12,600 ~ 16,650 hrs

Assume plastic concrete, strength 1~2 MPa, used for Cut-Off Wall.

(12,600 ~ 16,650)hrs/(20 hrs/day x 26 days/month x 2 rigs) = 12 ~ 16 months

Above estimation is exclusive of equipment mobilization and commissioning, site preparation (guide wall, working plateform, set-up of slurry plant and pipes), , changing of working phases, monsoon and demobilization.

6. Cut-Off Wall Plastic Concrete Mix

See Appendix B

7. Estimation on Diesel and Bentonite Consumption

Diesel for BC 32 on HS 885: 800 – 1000 litre/day (20 working hours), per unit

Service crane: 150 – 200 litre/day (20 working hours)

Generators (total 1000 KVA): 2000 – 2500 litre/day (20 working hours)

Backhoe: 80 – 120 litre/day (20 working hours)

Bentonite (for slurry only): 80 kg/m3 (total approximate 9,400 ton based on excavated wall volume 117,550 m3 )

The values are estimated figures based on past project experience. They are tabulated without liability.

8. Required Material for First Starting Due to the jobsite situation and equipment transportation schedule, 2 months operation time before the coming raining season maybe achieved. Based on the experience of other COW projects, the COW output of first 2 months will be lower than average because of some reasons like operator training, site arrangement..etc. One single bite panel (for 60m deep) per day is a fair production rate. 60m x 1.0m x 2.8m x 60 days = 10,080 m3

The estimation material for COW construction for 2 months (10% additional): (THIS ESTIMATE IS BASED ON THE MIX DESIGN OF PREVIOUS PROJECT) Item Material Quantity Remark 1 Cement 1,700 ton 2 Bentonite 220 ton For plastic concrete 3 Aggregate 20mm 6,300 ton 4 Aggregate 10mm 2,720 ton 5 Sand 9,100 ton 6 Bentonite 300 ton For bentonite slurry

As such quantity of sand and aggregate are required to start the COW construction. The sand and gravel on the downstream (or upstream) should be used after laboratory test.




9. Safety Equipment

The safety is the priority of all kind of construction jobsite. All workers on COW site must be protected by proper safety gears, such like hardhat, safety boots / rubber boots, gloves, safety glasses for welder, safety belt for high operation… etc.




Appendix A

Preliminary Schedule

of

Cut-Off Wall Construction




APPENDIX B

PLASTIC CONCRETE

MIXING DESIGN and TESTING




Due to the plastic concrete mixing design has not been finalized yet, the concrete mixing ratio of previous cut-off wall project at Dhauliganga H.E. Project in India 2002~2003 list in table B1 for your reference. The material (sand, aggregate, bentonite…etc.) for Tamanthi COW are also pending, Bauer recommend to prepare few sample with the material, what will be used to construct COW for laboratory test, and also to prepare a testing cell to execute pumping test and excavation to approve the permeability of plastic concrete satisfy the design requirement and joints inspection. Testing cell arrangement see figure B.1.

Typical Mixing ratio for one batch: Cement 150kg Water 318kg Sand 816kg Aggregate 10mm* 245kg Aggregate 20mm* 571kg Bentonite 20kg * Crushed rock. Plastic concrete figures: Slump 165~195mm Air content 1.4~1.7% Unconfined strength 1.5~2.5MPa Confined strength 2.5~3.5MPa Strain failure (unconfined) 5~7% Permeability 1x10-8m/s Young’s modulus Es 200~400MPa

Table B1, Plastic concrete mixing ratio and specification of Dhauliganga H.E. Project, India The mix design has to be approved by the PROJECT CONSULTANT prior to commencement. After erection and commissioning of the BC cutter a trial cut is proposed to be performed downstream of the cut off wall. This single cut shall be left open for several days whilst the Bentonite level is maintained. The trial panel will show the cutter’s workability to the final depth and allow to find important data on the stability of the trench. Upon completion of the test, the trench shall be bachfilled with Cement Bentonite mix. Suitability Test: A test cell may be constructed to test the suitability of the overall system. The ideal location of Test Cell is near the existing borehole which with clear bedrock information. The testing cell is a combination of 6 panels, one large 6.8m primary panel with triple bite excavation, two 2.8m primary panels, and three 2.8m secondary panels with 300mm over-cut length on both sides. The depth of COW panel should key into suitable rock as the PROJECT CONSULTANT requirement (2m rock socketing). Pumping test shall be executed 7 days after complete the concreting of last panel. Excavation in the middle to inspect the over-cut joints shall be executed 28 days after the testing cell completed. (Permeability test see figure B.2) The following will be monitored during testing cell installation:

Equipment performance Vertical tolerance of trench excavation




Trench stability The emphasis at the cell inspection will be on:

Mixing design Panel joints In situ Plastic concrete tests

12002800 2800

4600

6800

2200

100 300

300

2800

Overcut

Overcut

PT-1 PT-2

Pumping Test

Primary Panel P1

Primary Panel P2

Sec

onda

ry P

anel

S1

Sec

onda

ry P

anel

S2

300 300

2800

2200 28002800

Primary Panel P3Secondary Panel S3

7800

100

12002800 2800

4600

6800

2200

100 300

300

2800

Overcut

Overcut

Primary Panel P1

Primary Panel P2

Sec

onda

ry P

anel

S1

Sec

onda

ry P

anel

S2

300 300

2800

2200 28002800

Primary Panel P3Secondary Panel S3

7800

100

Figure B.1, Testing cell arrangement

Site Laboratory Due to the Tamanthi H.E. Project locate in a certain remote area, once the construction start, a site laboratory is recommended to execute most of testing on site. All testing items shall be subject to PROJECT CONSULTANT, recommend typical testing for COW construction are:

Material testing: (Sand, Gravel) Sieve analysis Clay content Silt content Bentonite slurry testing: Viscosity test Density test Sand content test pH value test Plastic concrete testing: Unconfined/confined strength test Permeability test Young’s modulus test Strain failure test Slump test …etc.




Figure B.2 Falling Head Permeability Test Method

(According to Geoguide 2 “Guide to site investigation”, HongKong geotechnical engineering office)




Appendix C

Further Soil Investigation




Further soil investigation Based on the available information on site, most of the soil investigation borehole stopped at 50m depth. So far, those SI data are not able to identify the sound rock level clearly. Further soil investigation down to sound rock level is necessary. The ideal location of borehole should combine the geophysical data and existing profile, 2 boreholes should located at the deepest rock level area on the dam axis (see figure 7.1). Then further SI at every 50~100m on the dam axis to clearly identify the rock level are recommended.

2 boreholes at deepest rock level area

Figure 7.1 Further soil investigations


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