kenji watanabe - École des ponts...

Railway Technical Research InstituteRailway Technical Research Institute

The Shinkansen: The Japanese high speed railway

through the technical history of civil engineering

structure

Kenji WATANABE

Le Shinkansen : réseau ferroviaire Japonais

à grande vitesse et ouvrages de Génie Civil

IFSTTAR, FRANCE Railway Technical Research Institute, JAPAN

Lundi 1er Juin 2015 Think & Build


1. How does the Shinkansen network remain safe in a country with

so many natural disasters?

2. How do the earth structures satisfy the high technical

performances required for the Shinkansen?

3. How may geosynthetics improve the behavior of high speed

railway earth structure?

1. Comment le réseau du Shinkansen parvient-il à demeurer sûr

malgré les nombreux risques naturels au Japon?

2. Comment les ouvrages géotechniques répondent-ils aux

performances techniques élevées exigées par le Shinkansen?

3. Comment les géosynthétiques peuvent-ils améliorer le

comportement des ouvrages géotechniques pour le réseau

ferroviaire à grande vitesse?

Questions


Contents

3. Railway structures for Shinkansen in Japan

1. Introduction of RTRI

5. Development of GRS structure

4. Experience during first generation of Shinkansen

2. Main Features of Shinkansen

6. Application of GRS technique to bridge abutment

7. Current research theme


• JR (7 railway companies)

– JR Hokkaido

– JR East

– JR Central

– JR West

– JR Shikoku

– JR Kyushu

– JR Freight

JR Hokkaido

JR East

JR Central

JR West

JR Kyushu JR Shikoku

JR Freight

RTRI

JR (Japan Railway) Group

(1987:Division and privatization)

4

Railway Technical Research Institute •Vehicle structure technology

•Vehicle control technology

•Structures technology

•Power supply technology

•Track technology

•Disaster prevention technology

•Signaling & Transport Information technology

•Materials technology

•Railway dynamics

•Environmental engineering

•Human science

•Maglev systems technology

•Center for Railway Earthquake Engineering Research

•Concrete Structures

•Steel and Hybrid Structures

•Foundation and Geotechnical Engineering

•Tunnel Engineering

•Architecture

7

Foundation and Geotechnical

Engineering lab. Earth structure group (3 permanent + 3 temporal researchers)

Foundation structure group

(3 permanent + 4 temporal researchers)

Maintenance group (3 permanent + 3 temporal researchers)

Publishing design standard for railway structure (Technical guide line, practical manual, software etc)

Supporting railway company (JR) especially after

natural disaster (large earthquake, heavy rainfall)

Final goal of our researchs are……

Design standard for earth structure(2007)

19 researchers

8

We have to rush to the site after the

natural disaster in order to decide

“How to restore?”

“Is it possible to restart the train

operation?”

and evaluate

“Why did it collapse?”

It is necessary to have enough

experience and knowledge, such as・

1.Basic soil mechanics

2.Stability of earth structure

3.Available countermeasure and

reinforcement method

4.Cost conscious for restoration

work 9

Contents








Kago

shima-

Chuo

Hakata

Tokyo Nagoya

Nagano

Shin-Osaka Nagasaki

Sanyo Shinkansen

Kyushu Shinkansen

Hachinohe

Morioka

Sapporo

Shin-Aomori

Sendaii

Tsuruga

Total length in operation :

approx. 2,400km

2010

2002

1982

1982

1997

1964

1975

2011

2004

Maximum

Speed:

300km/h

Shinkansen is a backbone line

supporting nation’s Development

JR East

JR Central

JR West

JR Kyushu

Under Construction

Planned line

Niigata

Courtesy of MLIT

Maximum

Speed:

260km/h

Maximum

Speed:

320km/h

Tohoku Shinkansen

Tokaido Shinkansen

Maximum

Speed:

270km/h

Contents








Kago shima-Chuo

Hakata

Tokyo Nagoya

Nagano

Shin-Osaka Nagasaki

Hachinohe

Morioka

Sapporo

Shin-Aomori

Sendaii

Tsuruga

2010

2002

1982

1982

1997

1964

1975

2011

2004

Three generations of Shinkansen

Niigata

Courtesy of MLIT

Tokaido Shinkansen

Maximum Speed:

270km/h

First generation: Tokaido (opened 1964)

Length ratios of different structure types for Shinkansen.

First generation: Tokaido (1964)

54 % of the total length is embankment:

1) long-lasting and large residual settlement

2) low stability against rainfalls & earthquakes

→ Long-lasting maintenance (even until today!), extremely costly

Earth structure Viaduct Bridge Tunnel

Kago shima-Chuo

Hakata

Tokyo Nagoya

Nagano

Shin-Osaka Nagasaki

Hachinohe

Morioka

Sapporo

Shin-Aomori

Sendaii

Tsuruga

2010

2002

1982

1982

1997

1964

1975

2011

2004


Niigata

Courtesy of MLIT

Sanyo Shinkansen

Maximum Speed:

300km/h

Maximum Speed:

320km/h

Tohoku Shinkansen

Second generation:

Sanyo (1975), Joetsu (1982) & Tohoku (1982)

Second generation: Sanyo (1972), Joetsu (1975) & Tohoku (1982)

RC viaduct (frame structures) & bridges in place of embankments:

but, 1) costly

2) not environmental friendly where on-site soil from

excavation of slope, tunnel etc. is available


Kago shima-Chuo

Hakata

Tokyo Nagoya

Nagano

Shin-Osaka Nagasaki

Hachinohe

Morioka

Sapporo

Shin-Aomori

Sendaii

Tsuruga

2010

2002

1982

1982

1997

1964

1975

2011

2004


Niigata

Courtesy of MLIT

Third generation:

Hokuriku (1997), Kyushu (2004) & Hokkaido (2016)

Kyushu Shinkansen

Maximum Speed:

260km/h

Third generation: Hokuriku (1997), Kyushu (2004) & Hokkaido (2016)

Revival of soil structures because of high performance &

low construction/maintenance cost:

● small residual deformation → slab tracks

● highly stable against rainfalls, floods, earthquakes

● environmental friendly when on-site soil from excavation of

slope, tunnel etc. is available


Geosynthetics

Reinforced

Soil structures

(GRS)

Continuous RC slab roadbed

Rail

Slab CA mortar

Subgrade RC roadbed

Joint Tie bar

- Relatively high construction cost

- But, largely reduced maintenance cost

- Very small allowable settlement of subsoil →

1) not constructed on conventional embankments;

but,

2) constructed on GRS structures

Three generations of structures for

Shinkansen in Japan

RC viaduct

[From 1972, Sanyo.

Joetsu & Tohoku] - High cost

- No use of excavated soil

Conventional type RWs

Gentle slope

[Tokaido, opened 1964] - Often stop/speed-down of train by

heavy rainfalls

- Low stability against earthquakes

- Larger deformation and bumps

behind bridge abutments,

→ very costly long-lasting

maintenance & reinforcing

- Occupation of wide space

Embankment;

54 % of the total length

and

Where relevant

(basically no piles)

GRS RW

・High stability (rainfalls, earthquakes)

・High cost-effectiveness

in construction & maintenance

[Since 2000]

70 (18)

123 (8)

20

194 (1)

26

Total wall length: 158 km

Total number of site:

GRS RWs: 1016

GRS bridge abutments: 33

GRS integral bridges: 4

Zero problematic case during and

after construction

222 (3)

No. of GRS RWs

148 (1)

220 (6)

Locations of GRS RWs (June 2014)

(No. of GRS bridge abutments

& GRS integral bridges)

Contents








Opening of Shinkansen Shinkansen CTC Center

Tokaido Shinkansen (1964.10.1)

Service section: between Tokyo and Shin-osaka (Distance: 515.4 km)

Time: 3 hours 10 minutes

Maximum speed: 210 km/hr

Tokyo Olympic (1964.10.10 - 10.24)

Much infrastructure (Shinkansen,

highway, Metropolitan Expressway)

were constructed just before

the Tokyo Olympic.

<Metropolitan Expressway, Tokyo>

Construction period was too short !

Earth structure for Tokaido Shinkansen (1964)

54% of structure is consist of earth structure. Construction was

completed within only 2 years (1961-1963)

Embankment : 24,000,000m3 (average height : 6m)

Cutting:6,000,000m3

Constructed wasted soil or Volcanic soil were mainly used for

the banking material

Sanyo

Tokaido

Tokyo

Osaka

Tokyo-Osaka:515.4km Maximum speed

210 km/hr(1964) 270km/h

- https://database.yomiuri.co.jp/shashinkan/ - M.Ishii: The reinforcement of embankment of Tokaido-Shinkansen against heavy rainfall, The Journal of Japan Railway Civil Engineering Association, 2003 (in Japanese)

Low stability against rainfall

Labor type Total length

Spot surfacing leveling of track

2998km

Compaction of ballast 1053km

Lining of track 1929km

Total 5980km

Maintenance work of Tokaido Shinkansen

just after the opening (1965/4-1966/3)

Total length of maintenance work is so long within only 1 year.

(Tokyo-Osaka: 515.4km)

Iwao Nisugi: Story of the maintenance work for Shinkansen (新幹線保線ものがたり）, Sankaido,

2006 (in Japanese)

Labor type Total cost (1 year)

Japanese Million Yen Million €

Spot surfacing/ leveling of track 10,690 79.2

Compaction of ballast 1,350 10.0

Lining of track 3,210 23.8

Total 15,250 113.0

Maintenance cost of Tokai-do Shinkansen

just after the opening (1965/4-1966/3)

Total cost for maintenance per year is so high!

(2013: approximately 274 Million €/year)

* Present values are estimated from consumer price index(CPI)

*1€=135 JPY

It is better to consider the Life Cycle Cost (not only initial

cost!!)

Sanyo Shinkansen (1975)

Service section: between Osaka and Hakata(Distance: 553 km)

Earth structure is less than 15% of the total structure

Sanyo

Tokaido

Tokyo

Osaka

Osaka-Hakata:553km Maximum speed

210 km/hr(1975) 300km/h

Hakata

1972

Osaka-Okayama

Construction cost for unit length was increased by 125%. This is mainly caused by the increase of bridge, viaduct and tunnel.

Construction cost of Shinkansen

Total Length

Total Construction

cost(Million €)

Total Construction cost per kilometer

(Million €/km)

First generation (Tokaido ,1964)

515km 14,120 27.4

Second generation (Sanyo, 1975)

553km 18,980 34.3

* Present values are estimated from consumer price index(CPI) in Japan

*1€=135 JPY


How can we construct an earth structure,

which does not require,

Much maintenance work

Much land for construction

(especially at transition zone)

(land acquisition cost is very high )

Retaining structure is

better to reduce the land

for construction.

? (between the structure and backfill embankment)


Terre-Armée method Terre-Armée method was introduced to Japan around 1967

Terre-Armée was applied around 1970’s for Japanese Railway,

but there were some technical problems.

Corrosion of metal strip caused by electric current There is no design method against large earthquake

(This problem have already been solved)

Japan Railway started to develop other reinforced-

soil structure using Geosynthetics from 1990’s


Contents








Laboratory Test (retaining structure)

Loading set-up Molding specimen

Bellofram cylinder

(unit:mm)

Membrane Grease

Load cell

Bearing

Load cell

footing Load cell

Imbrications

Acryl

810 410 1220 400

60

0

Types of Facing

FOOTING SURCHARGE 32gf/cm2 15cm STIFFENER

STEEL BAR

ROUGH

REINFORCEMENT

ROUGH

ROUGH

ROUGH

not fixed

SMOOTH SOFT MATERIAL

TRACING PAPER

RUBBER MEMBRANE

5cm

×10=50cm

ROUGH ROUGH ROUGH

Large Small Rigidity of Facing

TYPE D TYPE C TYPE B TYPE B’ TYPE A

AV

ER

AG

E F

OO

TIN

G P

RE

SS

UR

E,

q (

kP

a)

FOOTING SETTLEMENT(mm)

D

C

B’

B

A

5

10

15

20

0 5 10 15 20

Load-Bearing Behaviors

FOOTING SETTLEMENT(mm)

(b) Loading at forward

A

B

B’

C

D

20

40

60

80

0 5 10 15 20

(a) Loading at backward


Sand backfill

Clay backfill

Construction of Full-Scale Test Embankment

Three Tested Sections of Embankment (Sand)

Plan

Section Ⅰ 5

.0m

Ⅰ S

Ⅰ N

Ⅱ S

Ⅱ N

Ⅲ S

Ⅲ N

Section Ⅱ

Section Ⅲ

2.0m

1.5m

2.0m

Ⅰ Ⅱ Ⅲ

Ⅰ Ⅱ Ⅲ

SEGMENT ⅡN

SEGMENT ⅠN SEGMENT ⅢN

Loading Test Set-up

Load-Displacement Relations

q0

ⅢN (2.0m)

ⅠN (2.0m)

q d ⅡN (1.5m)

0

150

300

AVERAGE FOOTING PRESSURE, q(kN/m2)

HO

RIZ

ON

AL O

UT

WA

RD

DIS

PL

AC

EM

EN

T

AT

TH

E T

OP

OF

FA

CIN

G, d

(mm

)

450 50 200 400 600

Discrete panels

Continuous rigid facing


Deformation after Loading Test

Segment

ⅢN Discrete panel

The wall became more

stable as the rigidity of

facing increased.

Long term stability was also

confirmed from this full

scale test embankments.


Geosynthetics Reinforced Soil Retaining Wall

CONTINUOUS

GEOTEXTILE

(GRS RW)

After construction

Continuous

Rigid Facing

Reinforced-soil retaining wall at Nagoya


6) PLACING

CONCRETE FACING

5) LAYING COMPLETED 4) SECOND LAYER

3) BACKFILL AND

COMPACTION

2)

GABION

GEOSYNTHETICS

1) PLACING

BASE CONCRETE

DRAINAGE

LAYING GEOSYNTHETICS

AND SANDBAG

Construction procedure(staged-construction)


Overview of Reinforced-soil wall

Three main elements: soil, reinforcement, and facing

Terre Armée

6)6) Casting-in-place

RC facing

5)5) Completion of

wrapped-around wall


RC facing

5)5) Completion of

wrapped-around wall

<GRS-RW> (Geosynthetics Reinforced Soil-Retaining wall)

Functions of Facing?


Terre Armée

What are the functions of facing??


RC facing

5)5) Completion of

wrapped-around wall


RC facing

5)5) Completion of

wrapped-around wall

1)Earth pressure does not act on the facing.

This is because the reinforcement reduces

the earth pressure

2)Facing is used only for covering the backfill,

preventing from local erosion, local failure

and ultraviolet wave

Question

(geosynthetics or metal strips) True

or false?

GRS structure



If we could put in place one layer of grains in contact with

one layer of reinforcement, then one layer of grains, and so

on, we should not have any need for a facing.

The facing retains the grains located near the exterior

between two layers of reinforcement; it corresponds to a very

local problem, and is not important.

Henri Vidal (Inventeur de la Terre Armée)

Vidal, H. : The development and future of Reinforced

Earth, Keynote Address, Proc. of Symposium on

Earth Reinforcement, ASCE , pp.1～61,1978.

It seems that functions of facing is not important….



- Increasing the stiffness of the wall facing decreases the deformation

of the wall while increasing the lateral pressure applied to the facing.

F. Schlosser

Schlosser F. : Mechanically stabilized earth retaining structures in Europe,

Design and Performance of Earth Retaining Structures, Geotechnical Special

Publications No.25, ASCE (Lambe and Hansen), pp.347-378, 1990

The functions of facing is very important.

- Tensile force is large at the connection with the wall

- Wall resist against earth pressure (restrain the soil)

(Professor, Ecole Nationale des Ponts et Chaussees)

Lateral Facing Pressure

Wall

Heig

ht

Tensile

str

ess

Distance to facing

Earth pressure increases

Tensile force increases with compaction

Unstable

active zone

Available tensile forces when the connection

strength is zero, or if the facing is very flexible

Low tensile force

in the reinforcement

Low confining

pressure

→ No earth pressure at the

wall face

→ Low tensile forces in the

reinforcement, in particular

at the low wall level

→ In the active zone,

low confining pressure,

therefore, low soil strength

→ Low stability of the wall

Very flexible wall

Very stable

active zone

Well connected

Available tensile forces when the facing is rigid

enough & the connection strength is high enough

High tensile force

in the reinforcement

High confining

pressure

→ High earth pressure at the

wall face

→ High tensile forces in the

reinforcement

→ In the active zone,

high confining pressure,

therefore, high soil strength

→ High stability of the wall

Rig

id f

acin

g

Active zone

Reinforcement Potential active failure plane

Tensile force in

reinforcement

Active earth pressure, PA

A Facing

Two basic force equilibriums with reinforced soil walls:

(A) along the potential active failure plane

➔ always considered in design

Two basic force equilibriums with reinforced soil walls:

(A) along the potential active failure plane

➔ always considered in design

(B) at the facing ➔ very important, but often ignored

Active zone

Reinforcement Potential active failure plane

Tensile force in

reinforcement

Active earth pressure, PA

A

B

Facing

Paramount importance of connection strength

Development of Terre Armée

La peau metallique (U-shaped metallic elements)

Schlosser F. : “Henri VIDAL (1925 – 2007) Inventeur de la Terre Armée et Pionnier du

renforcement des sols ” http://www.cfms-sols.org/sites/default/files/manifestations/090325/Francois%20Schlosser.pdf#search='Terre+ar”mee+vidal'

Terre Armée at initial stage(1960’s) Development of a standard

cruciform facing panel (1971)

10m

Reasons for using facing panel

Vital: “ Appearance ”

Schlosser: “Various architectural possiblilities”

(Attractive and aesthetic))

(curving facing etc )

There are no explanations about

“earth pressure effect” which mobilizes higher tensile force in

reinforcement. (This is the another big advantage of using the facing panel !)

Development of Terre Armée

Development of GRS-RW GRS-RW at initial stage(1980’s) GRS-RW with rigid facing(1990)

embankment

Geosynthetics reinforcement

Displacement, deformation of

the GRS structure at the initial

stage were large.

This is due to the high

deformability of geosynthetics.

Displacement, deformation of

this GRS structure is quite

small even after the heavy

rainfall or earthquake.

What is the functions of facing??

Summary

1)The facing is an important and essential

structural component confining the backfill

and developing large tensile forces in the

reinforcement.

2) The earth pressure at the facing should be

high enough to provide sufficient confining

pressure to the backfill.

What is the disadvantage for using geosynthetics??

F. Schlosser (1990)

- The first geotextile reinforced wall

was built in 1971 by the LCPC.

- However, until now, their utilization

has been rather limited, because of

their high deformability.

- Geogrids have been widely used in

all areas of soil reinforcement,

except retaining walls.

- The problems related to the facing

must still be solved, specifically the

unaesthetic appearance of the

geogrid facing, difficulties in

construction, and the method for

attaching the geogrid to the facing

panel Schlosser F. : Mechanically stabilized

earth retaining structures in Europe, 1990

- It is not difficult to achieve strong facing/

reinforcement connection by constructing the wall

before backifill…

LCPC patented

similar technique of

geotextile reinforced

soil wall, called Ebal

wall, using precast

concrete facing

There are critical problems of this construction procedure

Damage to the connection due to relative

settlement between the facing and the backfill.

Large load

No tensile strains

before removing

the propping

Difficult compaction of the backfill

immediately behind the facing

Need for a

propping

Several problems if the wall constructed before, or

simultaneously with, the construction of the backfill

□ These problems can be solved by the

staged construction procedure …..

Uncontrolled movement

upon the removal of the propping

5) 5) Completion of

wrapped-around wall

4) 4) Second layer 3) 3) Backfilling & compaction

2) 2) Placing geosynthetic &

gravel gabions

Gravel gabion Geosynthetic

1) Leveling pad for facing

Drain hole

6) 6) Casting-in-place

RC facing

Staged construction - 1:

- Construction with a help of gravel gabions placed at the shoulder of each soil layer



5) 5) Completion of

wrapped-around wall



gravel gabions



Drain hole


RC facing

Lift = 30 cm

Good compaction of the backfill

No rigid facing during backfill

compaction

5) 5) Completion of

wrapped-around wall



gravel gabions



Drain hole


RC facing



5) 5) Completion of

wrapped-around wall



gravel gabions



Drain hole


RC facing

→ The facing/ reinforcement

connection is not damaged

during and after construction.

→ Construction using

compressive backfill on a

compressive soil layer

becomes possible.


- After sufficient compression of backfill and supporting

ground has taken place, a full-height rigid facing is constructed

by casting-in-place concrete directly on the wrapped-around wall.


Near Shinjuku Station, Tokyo,

constructed during 1995 – 2000

Geogrid

Central section

(11k340m)

2,9103,9132,9001,173 0.300

41,484

Gravel-filled gabions

(all units in mm)

640 1,000

3,000 2,000 2,500

34,570

200 100

6,9

14

230

21 x

300=

6,3

00

Full-height

rigid facing

384

Yamanote line

Chuo

line

Passenger: 6.4million/day

GRS RW supporting very busy urban trains in Tokyo

Full-height rigid facing becomes a

foundation for super-structures,

such as electric poles, noise barrier

walls, bridge girders etc.

H

H

3D effects of full-height rigid facing!


Immediately after completion, 1992

GRS RW with a FHR facing

for a rapid transit at Tanata

Geogrid

(TR= 29 kN/m)

H-shaped

pile

0.8 m

H= 4.5 m

0.5 m

A week after the 1995 Kobe Earthquake

The wall survived!

GRS RWs performed very well during severe earthquakes !

Performance of GRS-RW during severe earthquake


15 6

9

1418

2023 25

31

38

50

61

6872

76

83

94

110

116

122127

136

0

20

40

60

80

100

120

140

0

5

10

15

20

25

30

H1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

累計

施工

延長

（km）

年度

別施

工延

長（k

m）

ＲＲＲ－Ｂ工法施工実績（延長）

年度別施工延長累計施工延長

1995 2000 1990 2005

30

10

0

20

140

40

120

100

80

60

2010

Annual w

all

length

（km

）

To

tal （

km

）

1995 Kobe

Earthquake

Total

Annual

Restart of construction

of new high-speed train lines

(Shin-kan-sen)

2004 Niigata-ken-Chuetsu

Earthquake

2011 Great

East Japan

EQ

From 1982: research at the University of Tokyo & RTRI

Stiffness of facing

Soft (doesn’t accept earth pressure)

Hard (accept large earth pressure)

Strip,

band

(metal)

Planar,

Grid (Polymar)

Str

uctu

re a

nd M

ate

rial of

rein

forc

em

ent

embankment

Geosynthetics reinforcement

La peau metallique

no facing Full heigth rigid facing

Cruciform facing panel

Facing is not important, we should

not have any need for a facing.

Disadvantages of geosynthetics are

the high deformability and difficulties

in attaching the geogrid to the facing.

There is certain effect of facing

These disadvantages have

already been overcome

Many engineers are still

misunderstanding

Contents








Large subsidence of backfill of old

bridge abutment was observed (transition zone)

Typical damage of bridge abutment

Kobe earthquake (1995, M=7.3) Tohoku earthquake

(2011, M=9.0)

Well-graded gravel

Design and construction

management standard for

railway earth structure (1978)

(cement-mixed gravel are often

used in France)

N.Takahashi: ’Damage of railway bridge abutment at Tohoku earthquake’, Proc. of Japanese Society of Civil Engineering, 2012 (in Japanese)

Damage of bridge abutment

Large subsidence (max: 45cm) was observed behind the abutment

however Seismic input motion was not so large (max:214gal)

Transition zone was constructed by well-graded gravel

It became necessary to construct this transition

zone which is strong enough against seismic load

Hokkaido-Nansei earthquake, Tsugaru-Kaikyo line, 1993

Conventional type bridge abutment (Sinusoidal wave 450gal)

GRS bridge abutment (Sinusoidal wave 1000gal)

Cement-mixed gravel

Embankment

Bridge girder

Subsoil

Well graded

gravel

Bridge girder

Embankment

Subsoil

Geosynthetics

Shaking table tests of bridge abutment (Video)

Development of GRS for bridge abutment

Model tests(static loading tests, shaking table tests)

Numerical analysis

Bridge girder

Geogrid

reinforce -

ment

Cement - mixed gravel, reinforced with geogrid layers connected to the parapet

Uncemented backfill

RC facing structure

Bridge girder

Geogrid

reinforce-

ment

Cement mixed gravel,

reinforced with geogrid

layers

Uncemented

backfill

RC facing

(abutment)

Connected

Practical manual for design and construction management

Development of GRS for bridge abutment

Soil backfill

12

55

0

Cement-mixed gravel

Polymer geogrid R.L 1400

1000 Kyushu Island

Sedimentary talus

Crystalline schist

0 10 20 30 40 50

3

4

8

14

16

26 50/30

50/23

50/16

20% of cost reduction was realized by this proposed method

(Unit in mm) 150m

Application to the permanent structure of Shinkansen

Total cost

RC 0.61

0.28

Backfill 0.29

0.26

0.1

Reinforcement 0.29

Total=0.83

Soil backfill

11

75

0

7500

Well graded gravel

R.L 1800

1800

Soil backfill

1500

12

55

0

Cement-mixed gravel


1000

Proposed Type Conventional type

Sedimentary talus

Crystalline schist

0 10 20 30 40 50

3

4

8

14

16

26 50/30

50/23

50/16

Total =1.0

1)Conventional type

2) Proposed type

Conventional type versus new type (cost comparison)

Low construction cost & High seismic stability !

●２月２７日に水平載荷試験が行われた。

Lateral loading test, 27 February 2003

12.5m

Ｐ5（反力 1）Ｐ6（反力 2）Ａ1（補強土橋台） Pier 5 (reaction 1) Pier 6 (reaction 2) Abutment A1

(reinforced backfill)

Combined(reaction)

- Lateral loading test to ensure the connection

strength and the stability of the RC facing

- Residual displacement was only 10mm after the

horizontal loading (4000kN)

(14th Oct. 2011).

GCM: Ground improvement by cement-mixing

5.04 2.21.0

5.42.21.0

0.7 0.7

[All units in m]

GCM

Road surface

12.0

GCMGL= 5.0

Original

ground

Backfill (uncemented)Backfill (cement-mixed

gravelly soil)

6.1

10.75

EastWest RC slab

0.6

0.6

First full-scale GRS integral bridge, for a new high-

speed train line, Kikonai at the south end of Hokkaido

30 March 2011

Immediately after the earthquake at Koikoreobe

Sanriku Railway: - constructed 30 years ago taking into account

tsunami effects.

- However, three bridges were lost by the tsunami

during the 2011 Great East Japan EQ.

GRS integral bridge at Koikorobe for Sanriku Railway

19.93 m Geogrid-reinforced

Cement-mixed gravelly soil

Bed rock

Koikorobe stream

F F: Foundations

of the collapsed

bridge F

19.93 m

→To south

Ground

improvement

6.5 m 6.5 m 5.0 m

A2

1.8 m

P1

1.2 m

4.7 m

Local road 7.6

m

1.2 m

A1

0.6

m

A new HST line (Hokkaido Shinkansen)

GRS structure

Length or

number

Max. height

（m）

R GRS RW 3,528 m 11.0

A GRS abutment 29 13.4

I GRS integral bridge 1 6.1

B GRS box culvert 3 8.4

T GRS tunnel protection 11 12.5

Various GRS structures at Hokkaido Shinkansen (2013)

T

A

R

B

A

R

Applying to the earth cut with nailing

New generated ground

nailing

nailing

<Reinforced-cut soil retaining walls>

Almost same design

procedure of GRS

structure can be applied

Design standard for Earth Structure(2007)

Design standard for Earth Retaining Structure (2012)

Design standard for railway

structure

English version was published! (2015, 270 pages)

Design standards for retaining structure

These all structures are now covered in the same design standard (2012) (Performance based design)

The performances can be verified with an equivalent index

Type of structure

Reinforced-soil structure Conventional-type

Retaining wall

Bridge abutment

Reinforced-backfill retaining wall

trainsoil nailing

facing

train

traingeotextile

facing

geogrid

R.L

Cement-treated approach block

Reinforced-cut soil retaining wall

Earth pressure-resisting retaining wall

bedrockbackfill

Reinforced-soil bridge abutment

backfill

girdergirder

Approachblock

backfill

Earth pressure-resisting bridge abutment

Contents








Cement-mixed gravel is often used for

important structure for railway allowing a

limited amount of deformation.

What is Cement-treated gravel?

After the construction

Sedimentary talus

Crystalline

schist

0 10 20 30 40 50

3

4 8

14

16

26 50/30

50/23 50/16

Soil backfill

150

1255 Cement-mixed

gravel


100

(Unit in cm)

Tokyo Tokyo

Kyushu

Shinkansen

New type bridge abutment

Well-graded gravel with a little volume of cement;

geomaterial in-between soil and concrete.

Geogrid Tension member

Cement-mixed gravel

Compression member

Is there any other application of this composite material?

Applying to the construction of embankment on soft ground

as bending member (slab).

Embankment

Soft

ground

Improved pile

Conventional method

minimum

improvement

ratio is 25%

Proposed method

gravel

Embankment

Soft

ground

Geogrid

Improved pile

Cement-mixed

Bending loading Tests of

Cement-treated gravel slab

Cement-mixed gravel GeogridExternal load

(unit in mm)

200

700

50

Cement-mixed gravel

well-graded gravel, crushed sandstone cement/gravel ratio in weight : 2.5%

geogrid polymer geogrid, tensile strength: 30 kN/m

specimen two rectangular parallelepiped specimens

with geogrid and without geogrid

Bending loading Tests

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

0.0

-0.5

-1.0

-1.5

LoadingGeogridStrain gauge

A B C

Position of LDT

Crack observed previously

Specimen-1

Specimen-2

Tesile force

observed previously

C

rack

wid

th (

mm

)

Displacement at the loading point　[mm]

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

0

500

1000

1500

2000

2500

3000

Gauge A,C

Gauge B

location of strain gauge

Specimen-1 (with geogrid)

stra

in ()

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.40

1

2

3

4

5

6

7

ductile behaivior

Loading

L D T

Strain of geogrid

Relationship between load and displacement

Specimen-2 (without geogrid)

Displacement at the bottom of the specimen

Ver

tica

l lo

ad(k

N/m

)

Specimen with geogrid exhibited

ductile behavior after peak state

Cement-mixed gravel GeogridExternal load

(unit in mm)

200

700

50

This ductile behavior was

mobilized by the tensile strength

of geogrid

with geogrid

without geogrid

Application for the actual project (1) Construction of embankment on

soft ground at Japan railway

cement-mixed gravel

geogrid

Compaction of gravel

<After the ground improvement>

<Construction of the slab, 2009/4>

This composite material could be

constructed much easier and

faster than RC.

50% of cost reduction was

realized by this method

Volcanic clay (N-value: 2 -10)

φ=1.2m, L=6.2m

Improvement ratio: 10-14%

2 - 3m

6.2m

0.6m

Application for the actual project (2) Construction of embankment on

liquefied ground at Japan railway

<Arrangement of geogrid >

< Construction of the slab>

By allowing a slight global

subsidence (=even

subsidence) after the

earthquake, the embankment

was constructed without

ground improvement.

slab Liquefied ground

Possible application in the future

Construction of embankment on soft ground

It is easier to construct the slab which has high bending stiffness

and low permeability, compared to the construction of

Reinforced Concrete

Cement-Treated Gravel Soil Slab（Cement-treated gravel + geogird, 1m thick）

3000 3000

Black cotton

soil layer

Embankment

Supporting ground

It can reduce the differential settlement of the

embankment to the longitudinal direction of track

which often require the maintenance

199

0 199

1

Locations of railway

embankments that failed

by the 1990 and 1993

floods

Geosynthetics for erosion countermeasure

embankments that collapsed by flood in1990

North Oh-ita

1990 Site 2

A small drain pipe crossing the

embankment was clogged by

flowing timbers and a natural

reservoir was formed. The

embankment was fully eroded

by over-topping flood.

1994 GR RWs were adopted, due to:

a) fast construction;

b) small construction machines

necessary;

c) a high stability against heavy

rainfalls and earthquakes;

and

d) low cost for construction and

maintenance

Geogrid (rupture strength

TTR= 29.4 kN/m)

Gabions between the facing

and the backfill and a large-

diameter drainage pipe are not

shown.

Railway track

1V : 1.5H

1V : 1.5H

Geogrid (TTR= 58.8kN/m)

1V:0.2H

0.65 m

Secondary low-stiffness geogrid

for compaction control

26.5

m

11 m

7 m

Geogrid (rupture strength

TTR= 29.4 kN/m)

Gabions between the facing

and the backfill and a large-

diameter drainage pipe are not

shown.

Railway track

1V : 1.5H

1V : 1.5H

Geogrid (TTR= 58.8kN/m)

1V:0.2H

0.65 m

Secondary low-stiffness geogrid

for compaction control

26.5

m

11 m

7 m

Reconstruction to GR slope and GRS-RW in 1991

Site 2

A bigger overtopping flood, July 2012

Original unreinforced fill section,

survived the 1990 flood but fully

eroded by the July 2012 flood

Site 2

A bigger overtopping flood, July 2012

Site 2

GRS section, fully eroded by the 1990 flood,

restored in1991 and survived the July 2012 flood

Geogrid

Site 2

GRS section, fully eroded by the 1990

flood, restored in1991 and survived

the July 2012 flood

Original unreinforced fill section,

survived the 1990 flood but fully

eroded by the July 2012 flood (then

excavated for restoration works)

Gullies were formed in the unprotected

downstream slope by overtopping flood,

but the gullies did not further develop.

Non-woven geotextile

Erosion of railway embankment caused by heavy rainfall

20 November 2013

Downstream

River

Embankment

Overtopping

110

Erosion of railway embankment, coastal dike caused by Tsunami

Tsunami

1.How the embankment collapse during long-term overtopping

2.How to increase the resistance of earth structure against long-

term overtopping? (effect of slope protection, geosynthetics

etc….)

(caused by heavy rainfall or Tsunami)

JR Kesennmuma line (2011/3) Aketo Tanohara, Iwate prefecture (2011/3)

Pump No.2 ：2m3/min

Large overflowing model tests

Water tank

Pump No.1： 4m3/min

Water channel

Sand box

111

・Large earthquake before tsunami

・Long-term overflowing phenomena

・Erosion of supporting ground

Overflowing

Erosion of

embankment body

Erosion of

supporting ground

Propagation

of erosion

2 minutes after(Real scale：6 minutes)

112

Overflowing test on conventional embankment

Geogrid

Gabion

Concrete facing

Tsunami

Cement-treated

gravel slab

Simple facing connected

to the geogrid

Suggestion of new GRS embankment

Geogrid reinforced-soil

Anti-seismic Longer geogird at upper and lower part

Cement-treated gravel slab at the bottom

Anti-longterm overflowing

Comparison with the conventional type

・Narrow space for construction (steep slope)

・High stability (resistance) against earthquake and overtopping) 113

Longer

georgird

Cement-treated gravel slab

Overflowing 2 minutes after(Real scale：6 minutes)

Overflowing test on GRS embankment

No erosion

Erosion of

supporting ground

No propagation

of erosion

Conclusion Tokaido-Shinkansen (1964) It still requires much maintenance work for earth structure.

GRS structure It was developed in order to reduce the maintenance cost, land acquisition cost. It has already become a standard earth structure for Shinkansen.

GRS and Terre Armee The material, mechanism and construction procedure are quite different. However, the development from the initial stage is similar (applying harder facing).

Function of facing and disadvantage of geosynthetics There is certain effect of facing (earth pressure effect). The disadvantages of geosynthetics which were pointed out by Schlosser have already been overcome. Many engineers are still misunderstanding.

Thank you for your attention

Railway Technical Research Institute, JAPAN Structures Technology Division,

Foundation & Geotechnical Engineering Laboratory

Kenji Watanabe watanabe.kenji.71＠rtri.or.jp

kenji.watanabe＠ifsttar.fr

Départment Géotechnique, Environnement, Risque Naturels et

Sciences de la Terre (GERS)

IFSTTAR, FRANCE (until 31/10/2015)

(after 1/11/2015)

kenji watanabe - École des ponts...

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