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Railway Technical Research InstituteRailway Technical Research Institute
History of Japanese railway and
Development of Geosynthetics
Reinforced-soil Structure
Kenji Watanabe
The University of Tokyo, JAPAN
(formerly Railway Technical Research Institute, RTRI)
18, April, 2018 UK-IGS
1
Railway Technical Research InstituteRailway Technical Research Institute
JR Hokkaido
JR East
JR Central
JR West
JR Kyushu JR Shikoku
JR Freight
RTRI
2
Railway Technical Research Institute
Railway Information Systems Co., Ltd.
7 railway companies
1987Division and privatization
Railway companies in Japan
Japan national
railways
Publishing design standard
for railway structure(Technical guide line, practical manual, etc)
Supporting railway company (providing technical solutions)
Railway Technical Research InstituteRailway Technical Research Institute
Contents1. Background (Technical issues around 1990)
6. Overview of recent application
2. Development of GRS retaining wall(1990’s)
3
4. Design of GRS RWs
3. Application of GRS to bridge abutment(2000’s - 2010’s)
5. Advantages of GRS RWs
7. Other examples of GRS structure
Kago
shima-
Chuo
Hakata
TokyoNagoya
Nagano
Shin-OsakaNagasaki
Sanyo Shinkansen
Kyushu Shinkansen
Hachinohe
Morioka
Sapporo
Shin-Aomori
Sendaii
Tsuruga
Total length in operation : 2,764km
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
UnderConstruction
Planned line
Niigata
4
Courtesy of MLIT
Maximum
Speed:
260km/h
Maximum
Speed:
320km/h
Tohoku Shinkansen
Tokaido Shinkansen
Maximum
Speed:
270km/h
Earth Structure 82%
Type of Structure and Composition of Japanese Railway
Conventional
lines
(24300km)
Shinkansen*
lines
(2400km)
21%
Earth Structure
Bridge
Tunnel
Viaduct
Bridge, Viaduct 48% Tunnel 31%
8% 10%
*Shinkansen : High speed bullet train in Japan 5
Tokaido Shinkansen (1964)Ballasted track on embankment
Bearing capacity of embankment was not very high.(using clay, low compaction control etc)Settlement of ballasted track became very large after opening.
Kagoshima-Chuo
Hakata
TokyoNagoya
Nagano
Shin-OsakaNagasaki
Hachinohe
Morioka
Sapporo
Shin-Aomori
Sendaii
Tsuruga
2010
2002
19821982
1997
19641975
20112004
Niigata
2016
Track Type of Japanese Railway
6
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
7
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 !
8
Tokaido Shinkansen (1964)Ballasted track on embankment
Bearing capacity of embankment was not very high.(using clay, low compaction control etc)Settlement of ballasted track became very large after opening.
Kagoshima-Chuo
Hakata
TokyoNagoya
Nagano
Shin-OsakaNagasaki
Hachinohe
Morioka
Sapporo
Shin-Aomori
Sendaii
Tsuruga
2010
2002
19821982
1997
19641975
20112004
Niigata
2016
Sanyo Shinkansen(1975)Slab track on viaduct.
Hokuriku Shinkansen(1997)Slab track on high quality embankment
Track Type of Japanese Railway
9
Continuous RC slab track
Rail
SlabCA mortar
SubgradeRC roadbed
JointTie bar
Relatively high construction cost
Very small allowable settlement of subsoil
Large reduction of maintenance cost
Less than 15cm (Restorability after severe EQ)
10mm/10years (Serviceability)
10
11
Technical issues around 1990s
Earth structure which is strong enough
against natural hazard
How can we construct ?
Earth structure which can support slab track
Earth structure with minimum land acquisition
Material selection and
sufficient compaction
Railway Technical Research InstituteRailway Technical Research Institute
Co
ncr
ete
road
bed
Trac
k
CA mortar 50mm
Reinforced concrete300mm
Well graded crushedstone 150mm
Prime coat
Sub
grad
e(e
mb
ankm
ent)
Slab
Subgrade
Drainage Layer
Slab
Filling layer (CA mortar)
Reinforced concrete
Well gradedcrushed stone
Slab track on earth structure(Example in cutting section)
Slab
Concrete roadbed
Subgrade
12
Subgrade:K30 ≧ 110MN/m3
Cross section of slab track on earth structure
13
Major categories Medium categories Minor categoriesSoil material category Soil category Categorized mainly by observation Categorized by triangular coordinates
Coarse soil Cm
fraction > 50%
Gravel soil [G]
Gravel fraction >
sandy fraction
Sandy soil [S]
Sandy fraction ≧gravel fraction
Fine fraction <
15%
Fine fraction <
15%
Gravel containing fine
fraction [GF]
15% ≦ fine fraction
Sand containing fine
fraction [SF]
15% ≦ fine fraction
Gravel [G]
Sand fraction < 15%
Sandy Gravel [GS]
15% ≦ Sand fraction
Sand [S]
Gravel fraction <
15%
Gravely sand [SG]
15% ≦ gravel fraction
Gravel [G]
Fine fraction < 5%
Sand fraction < 5%
Gravel containing sand [G-S]
Fine fraction < 5%
5% ≦ Sand fraction < 15%
Gravel containing fine fraction [G-F]
5% ≦ Fine fraction < 15%
Sand fraction < 5%
Gravel containing fine sand [G-FS]
5% ≦ Fine fraction
5% ≦ Sand fraction < 15< 15%%
Sandy gravel [GS]
Fine fraction < 5%
15% ≦ Sand fraction
Sandy gravel containing fine fraction [GS-F]
Fine fraction < 5%
15% ≦ Sand fraction
Fine-grained gravel [GF]
15% ≦ Fine fraction
Sand fraction < 5%
Fine gravel containing sand [GF-S]
15% ≦ Fine fraction
5% ≦ Sand fraction < 15%
Fine sandy gravel [GFS]
15% ≦ Fine fraction
15% ≦ Sand fraction
Sand [S]Fine fraction < 5%
Gravel fraction < 5%
Sand containing gravel [S-G]Fine fraction < 5%
5% ≦ Gravel fraction < 15%
Sand containing fine fraction [S-F]5% ≦ Fine fraction < 15%
Gravel fraction < 5%
Sand containing fine gravel [S-FG]
5% ≦ Fine fraction < 15%
5% ≦ Gravel fraction < 15%
Gravel Sand [SG]
Fine fraction < 5%
15% ≦ Gravel fraction
Fine Sand [SF]5% ≦ Fine fraction < 15%
15% ≦ Gravel fraction
Fine sand [SF]15% ≦ Fine fraction
Gravel fraction < 5%
Fine sand containing gravel [SF-G]
15% ≦ Fine fraction
5% ≦ Gravel fraction < 15%
Fine gravely sand [SFG]15% ≦ Fine fraction
15% ≦ Gravel fraction
Gravel
Group A :(For slab track)
Group B:(For ballasted track)
Material for subgrade (upper part of embankment)
Degree of compaction (Dc) ≥ 95%
K30 ≥ 110MN/m3
Degree of compaction (Dc) ≥ 90%
K30 ≥ 150MN/m3
Upper part of the embankment
Lower part of the embankment
Gravel: Dc ≥ 90%
Sand : Dc ≥ 95%
Compaction control for subgrade for slab track3
m
Lower part
Upper part 0.3m
1:1.8
1.5m
Extended geogrid
Short geogrid
<Plate loading test>
※Dc=100 x rd/rdmax
or
15
0 100 200 300 400 0.000
0.001
0.002
0.003
0.004
路床の残留沈下率
路床の K30値(MN/m3)
○:細粒分質砂 ●:細粒分質砂 ▲:礫質砂 ■:砂質礫 白抜き:有道床軌道 黒抜き:省力化軌道
Resid
ual sett
lem
ent
ratio
K30 of subgrade
Sandy gravelGravely sand
Fine sandFine sand
White: Ballasted trackBlack: Ballastless track
K30 vs residual settlement
80 90 100 110 0.000
0.001
0.002
0.003
0.004
路床の残留沈下率
路床の締固め密度比(%)
○:細粒分質砂 ●:細粒分質砂 ▲:礫質砂 ■:砂質礫 白抜き:有道床軌道 黒抜き:省力化軌道
Sandy gravel
Gravely sand
Fine sand
Fine sand
White: Ballasted track
Black: Ballastless track
Degree of compaction Dc (%)
Resid
ual sett
lem
ent
ratio
Full-scale loading test result(after 1.5 million cyclic loading)
Dc vs residual settlement
16
Technical issues around 1990s
Earth structure which is strong enough
against natural hazard
How can we construct ?
Earth structure which can support slab track
Earth structure with minimum land acquisition
Material selection and
sufficient compaction
Retaining structure
Terre-Armée method
Terre-Armée was applied around 1970’s for Japanese Railway,
but there were some technical problems.
Corrosion of metal strip caused by electric currentThere is no design method against large earthquake
Japan Railway tried to develop other reinforced-
soil structure using Geosynthetics from 1988(Collaborative research between RTRI and Univ. of Tokyo) 17
Contents1. Background (Technical issues around 1990)
6. Overview of recent application
2. Development of GRS retaining wall(1990’s)
18
4. Design of GRS RWs
3. Application of GRS to bridge abutment(2000’s - 2010’s)
5. Advantages of GRS RWs
7. Other examples of GRS structure
Laboratory Test
Loading set-up Molding specimen
Belloframcylinder
(unit:mm)
MembraneGrease
Load cell
Bearing
Load cell
footingLoad cell
Imbrications
Acryl
810 4101220 400
60
0
Railway Technical Research InstituteRailway Technical Research Institute
Sand backfill
Clay backfill
Construction of Full-Scale Test Embankment
Railway Technical Research InstituteRailway Technical Research Institute
Section Ⅰ5.0
m
ⅠS
ⅠN
ⅡS
ⅡN
ⅢS
ⅢN
Section Ⅱ
Section Ⅲ
2.0m
1.5m
2.0m
Ⅰ Ⅱ Ⅲ
Ⅰ Ⅱ Ⅲ
SEGMENT ⅡN
SEGMENT ⅠN SEGMENT ⅢN
Three Tested Sections of Embankment (Sand)
Plan
21
Railway Technical Research InstituteRailway Technical Research Institute
The rigidity of facing, connection between
facing and geosynthetics are very important.
Long term stability was also confirmed from this
full scale test embankments.
Vertical loading tests
22
Railway Technical Research InstituteRailway Technical Research Institute
Geosynthetics Reinforced Soil Retaining Wall
CONTINUOUS
Geotextile
(GRS RW)
23
Trademark
Railway Technical Research InstituteRailway Technical Research Institute
5)5) Completion of
wrapped-around wall
4)4) Second layer3)3) Backfilling & compaction
2)2) Placing geosynthetic &
gravel gabions
Gravel gabionGeotextile
1) Leveling pad for facing
Drain hole
6)6) Casting-in-place
RC facing
24
Geotextile
Construction procedure
After sufficient compression
of backfill and ground
鉄製のアンカー(直径
30 cm 30 cm120 cm
30 c
m
60 c
m
Backfill
Geogrid
Frame
Fresh
concreteSeparator
Steel reinforcement
Welding
Anchor
plate
60 cm
Soil
bagSteel rod (13 mm in dia.)鉄製のアンカー(直径
30 cm 30 cm120 cm
30 c
m
60 c
m
Backfill
Geogrid
Form
Fresh
concreteSeparator
Steel reinforcement
Welding
Anchor
plate
60 cm
Soil
bagSteel rod (13 mm in dia.)
Firm connection
Railway Technical Research InstituteRailway Technical Research Institute
6)6) Casting-in-place
RC facing
Firm connection
5)5) Completion of
wrapped-around wall
鉄製のアンカー(直径13 mm)
30 cm 30 cm120 cm
30 c
m
60 c
m
Backfill
Geogrid
Frame
Fresh
concreteSeparator
Steel reinforcement
Welding
Anchor
plate
60 cm
Soil
bagSteel rod (13 mm in dia.)鉄製のアンカー(直径13 mm)
30 cm 30 cm120 cm
30 c
m
60 c
m
Backfill
Geogrid
Form
Fresh
concreteSeparator
Steel reinforcement
Welding
Anchor
plate
60 cm
Soil
bagSteel rod (13 mm in dia.)
Casting-in-place concrete directly on the
geogrid-wrapping-around wall face:
1) Fresh concrete enters the gravel bags
through the aperture of the geogrid (PVA has
very high resistance against high PH).
2) A firm connection between the facing and the
reinforcement is ensured (PVA has a good
adhesiveness with concrete)
10 cm
Typical polymer geogrid:
bi-axial made of PVA
Railway Technical Research InstituteRailway Technical Research InstituteNear 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
26
GRS RW supporting extremely busy urban trains
Construction of backfill
Construction of rigid facing
Passenger: 6.4million/day
Railway Technical Research InstituteRailway Technical Research Institute
Kobe earthquake 1995 (M=7.3)
27
Many damages to conventional type RW
Railway Technical Research InstituteRailway Technical Research Institute
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!
Performance of GRS-RW during severe earthquake
28
GRS RWs performed very well during severe earthquakes !
Kobe earthquake (1995, M=7.3)
Railway Technical Research InstituteRailway Technical Research Institute
GRS RWs for railways (including high-speed trains) that had been
constructed in the affected area of the 2011 Great East Japan EQ
Co
Aomori: 58
Iwate: 23
Miyagi 9
Akita: 1
Yamagata: 3
Fukushima: 1
(total) 95
300 300 (All unit in mm)
100 575
100
600
5,400
Adjacent to Natori River,
Sendai City
Completed 1994
Wall length= 400 m
- Designed against very high seismic
load (level 2); and
- No damage to all the GRS RWs.
These facts validate the current
seismic design code for railway RWs. 29
Railway Technical Research InstituteRailway Technical Research Institute30Other application (bridge abutment)30
0
20
40
60
80
100
120
140
160
180
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 24 25 26 27 281995 20001990 2005 2010 2015
Total
1995 Kobe
Earthquake
Annual
Restart of construction
of new lines of HSR
(ShinKanSen)
2004 Niigata-ken-Chuetsu
Earthquake
Research: from 1982 at University of Tokyo
from 1988 at Railway Technical Research Institute
Tota
l (
km)A
nnual w
all
length
(km)
180
80
140
120
100
60
30
10
0
202011 Great
East Japan
EQ
Railway Technical Research InstituteRailway Technical Research Institute
Contents1. Background (Technical issues around 1990)
6. Overview of recent application
2. Development of GRS retaining wall(1990’s)
31
4. Design of GRS RWs
3. Application of GRS to bridge abutment(2000’s - 2010’s)
5. Advantages of GRS RWs
7. Other examples of GRS structure
Railway Technical Research InstituteRailway Technical Research Institute
Typical differential settlement at the transition zone
Bridgeabutment
Soft ground
Bearing layerpile foundation
Boxculvert
This transition zone is often suffering from differential subsidence which requires frequent maintenance works.
Differentialsubsidence
embankment embankment
Differential subsidence
Maintenance and reinforce of existing embankment at
transition zone are still major technical issue in Japan.
Railway Technical Research InstituteRailway Technical Research Institute
Application of GRS to the bridge abutment
(upside-down triangle shape)
Well-graded
gravel
Well-graded gravel
(trapezoidal shape)
In order to avoid a
sudden change of the
support rigidity, gravel
zone was change to
be trapezoidal shape
1967
1978
History of standard for railway structure
Isn’t it better to apply
GRS method to the
transition zone?
33
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
A modification of GRS-RW by
1. Placing a girder directly on the top of the facing
2. cement-mixing the backfill behind the facing.
34
Soil backfill
12
55
0Cement-mixed
gravel
Polymer geogridR.L 1400
1000 Kyushu Island
Sedimentarytalus
Crystallineschist
0 10 20 30 40 50
3
4
8
14
16
2650/30
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
35
Total cost
RC 0.61
0.28
Backfill 0.29
0.26
0.1
Reinforcement0.29 Total=0.83
Soil backfill
11
75
0
7500
Well graded gravel
R.L 1800
1800
Soil backfill
1500
12
55
0Cement-mixed
gravel
Polymer geogridR.L 1400
1000
GRS bridge abutment Conventional type
Sedimentarytalus
Crystallineschist
0 10 20 30 40 50
3
4
8
14
16
2650/30
50/23
50/16
Total=1.0
1)Conventional type
2) Proposed type
Cost comparison with conventional type
Low construction cost & High seismic stability !
Contents1. Background (Technical issues around 1990)
6. Overview of recent application
2. Development of GRS retaining wall(1990’s)
37
4. Design of GRS RWs
3. Application of GRS to bridge abutment(2000’s - 2010’s)
5. Advantages of GRS RWs
7. Other examples of GRS structure
Railway Technical Research InstituteRailway Technical Research Institute38
Design and construction of GRS RWs & Abutment
Design standard for railway structure
- Earth structure
- Earth retaining structure
- bridge abutment
- Seismic design
RRR-B Method
Material manual
RRR Method
Association
Earth structure
Earth retaining
structure
Performance based
Design
P.5-6
39
Soil
type
Classification
according to the Japanese
Geotechnical Society
γt
(kN/m3)
Seismiccondition(Level 2)
Non-seismiccondtion
Seismic condtion(Level 1)
φpeak(°) φres(°) φ(°)
1G, G-S, GSG-F, G-FS, GS-Fhard rock(low fissility)
20 55 40 40
2
S, S-G, SGS-F, S-FG, SG-Fhard rock(high fissility),soft rock fallSoft brittle rock
19 50 35 35
3GF, GF-S, GFSSF, SF-G, SFG 18 45 30 30
4ML, CL, MH, CHOL, OH, OV, Pt, MkVL, VH1, VH2
16 40 30 30
Determined by comprehensive laboratory tests and literature
investigation(252 samples total)
Compaction level for slab track
P.8-39Design values of backfill
Railway Technical Research InstituteRailway Technical Research Institute
Fellenius method
The stability for the failure
plane located below the base
of the facing depth of
embedment is examined.
Reinforcement
Facin
g
T n
T
TS
Mrd
M LdO
Failure plane
P.8-39External stability analysis of GRS-W
40
Axle load
Surcharge load
Railway Technical Research InstituteRailway Technical Research Institute
(surcharge loads)(external loads)
Backfill (Φ, c)
Design ground
surface Subsoil (Φg, cg)
facing geotextile
P.8-39Internal stability analysis of GRS-RW
Two-wedge method Searching 2 failure planes both
in reinforced zone and
unreinforced zone against
“Sliding” and “Overturning”41
Sliding mode Overturning
Axle load
Railway Technical Research InstituteRailway Technical Research Institute
42
P.8-39Design of wall facing
Wall facing is assumed as the elastic beam supported
by multi spring, which is assured by the strong
connection between wall facing and reinforcement
Wall facing thickness can be reduced as compared with
conventional retaining wall.
Axle load
43
5.6 Reinforcements used in reinforced-backfill retaining walls
The reinforcements used inreinforced-backfill retaining walls
shall be those whose qualityhas been ascertained and theircharacteristic values anddesign values shall beappropriately determined takinginto account various factors, such asthe variability of test values and theexperimental conditions.
<Geogrid>
<Laying of geotextiles>
[Notification]
α1: Reduction factor considering alkaline resistance
α2:Reduction factor related to damage during construction
α3: Reduction factor related to creep α4:Reduction factor for momentary load
α5:Reduction factor related to train load
Action combinationReduction factors(○:Considered)α1 α2 α3 α4 α5
Permanent action ○ ○ ○ - -
Permanent action+variable action
(train) ○ ○ - - ○
Permanent action+seismic action(L1
seismic ground motion)+secondary
variable action○ ○ - ○ -
Permanent action+seismic action(L2
seismic ground motion)+secondary
variable action○ ○ - ○ -
During construction - ○ - - -
44
Table 5.6.2 Combination of reductions factors used in calculation of material factor , feg
Railway Technical Research InstituteRailway Technical Research Institute
45
(1) Minimum thickness of the facing- Minimum thickness of facing : 200 mm (generally 300mm)
- The inclination of the front side of the facing :Vertical or 1:0.05 in V/H
(2)Arrangement reinforcementArranged every 30 cm; every 1.5 m in the vertical spacing
Basic length 1.5m or 35 % of H
H(W
all
hei
ght)
φ (Internal friction angle)
L
30cm
1.5m
Basic length
H45˚+φ/2
L
Structural details
Railway Technical Research InstituteRailway Technical Research Institute
Contents1. Background (Technical issues around 1990)
6. Overview of recent application
2. Development of GRS retaining wall(1990’s)
46
4. Design of GRS RWs
3. Application of GRS to bridge abutment(2000’s - 2010’s)
5. Advantages of GRS RWs
7. Other examples of GRS structure
Railway Technical Research InstituteRailway Technical Research Institute
Advantage of GRS RWs in construction
47
Conventional RWs GRS RWs
Extremely
weak
Relatively
weak
Good
Subsoil
condition
Railway Technical Research InstituteRailway Technical Research Institute48
Conventional RWs GRS RWs
Extremely
weak
Pile foundation and
ground improvement is
needed.
Ground improvement
is needed.
Subsoil
condition
①
④⑤
②
①
③
②
④
③
Advantage of GRS RWs in construction
Railway Technical Research InstituteRailway Technical Research Institute49
Conventional RWs GRS RWs
Relatively
week
RC facing can be constructed after settlement finished
Pile foundation is needed because settlement of the RWs is not allowed.
Subsoil
condition
①
④
②①
②
③
③
Advantage of GRS RWs in construction
Railway Technical Research InstituteRailway Technical Research Institute
Conventional RWs GRS RWsSubsoil
condition
①
②
③
Good
①②
③
Large footing is
required.Large footing is not
needed.
Advantage of GRS RWs in construction
Railway Technical Research InstituteRailway Technical Research Institute
51
Conventional RWs GRS RWs
Extremely
weak
Relatively
weak
Good
RC facing can be
constructed
after settlement
finished
Pile foundation is
needed because
settlement of the RWs
is not allowed.
Large footing is
required.
Large footing is not
needed.
Pile foundation and
ground improvement is
needed.
Ground improvement
is needed.
Subsoil
condition
Advantage of GRS RWs in construction
Railway Technical Research InstituteRailway Technical Research Institute
Backfill:
Backfill:
Ground (clayey soil, N=10,
20 m-thick)
soil density: 1.6 g/cm3;
ϕ= 0, c= 62 kPa)
Backfill:
soil density: 2.0 g/cm3
ϕ= 35o, c= 0
13.5 13.5
0.5 3.25 3.253.03.25 0.5
5.0
1.7
*dia.= 1.0 m; length: 20 m
c-to-c spacing in the track
direction: 4.0 m
Cast-in-
place
piles*2.54.5
Geogrid
(Tk= 37.5 kN/m)
Geogrid
(Tk= 76 kN/m)
Backfill:
Backfill:
soil density:
2.0 g/cm3
ϕ= 35o, c= 0
0.5 3.25 3.253.03.25 0.5
5.0
Leveling concrete
Gravel blanket 1.8
All units in m
Leveling concrete
Gravel blanket
Cost ratio for typical GRS RW versus conventional type RW
Construction Maintenance Total
20 m-thick relatively soft ground:
- piles for conventional type RWs
- no piles for GRS RWs
(the case shown in the figure)
0.32 0.5 0.33
Relatively stiff ground:
- no piles for conventional type
RWs & GRS RWs
0.81 0.51 0.77
Designed
by using
(kh)design= 0.2Cost of conventional
wall = 1.0
0.28 0.29
0.98 0.50 0.90
0.50
Railway Technical Research InstituteRailway Technical Research Institute
Contents1. Background (Technical issues around 1990)
6. Overview of recent application
2. Development of GRS retaining wall(1990’s)
53
4. Design of GRS RWs
3. Application of GRS to bridge abutment(2000’s - 2010’s)
5. Advantages of GRS RWs
7. Other examples of GRS structure
Railway Technical Research InstituteRailway Technical Research Institute
Sapporo
Kagoshima Chuo
Shin-Osaka
Nagoya
Tsuruga
Kanazawa
Omiya
Niigata
Tokyo
Nagasaki
In service 2,764.5 km(Since 2000: 929.4 km)
Under
construction
Hokkaido (extension) 211.5km
Hokuriku (extension) 125.2km
Kyushu (Nagasaki route) 66.0km
54
Hokkaidoopened March 2016
Shin-Hakodate Hokuto
Hokuriku
Kyushu(Nagasaki route)
to be completed 2022
Hakata
High-Speed Railway (HSR, Shinkansen), January 2017
Tokaidoopened Oct. 1964
Railway Technical Research InstituteRailway Technical Research Institute
211km
149km
Seikan tunnel (54km)
Shin-Aomori
Okutugaru
To Tokyo
Existing line (82 km)
Hachinohe Shichinohe-
towada
Kikonai
Shin-Hakodate
Shin-Yakumo
Oshamanbe
Kuthyan
Shin-Otaru
Sapporo
Hokkaido Island
Main Island
Toh
oku
Sh
inka
nse
n
Hokka
ido
Sh
inka
ns
en
Shin-Yakumo
Hokkaido High-Speed Train Line (Shin-kansen)
Completed
Construction
started 2013
Opened 26 March 2016
A number of GRS
structures were
densely constructed in
place of conventional
type structures
Railway Technical Research InstituteRailway Technical Research Institute
GRS structures
for Hokkaido HST line;
1) GRS retaining walls having full-height
rigid facing for a length of 3.5 km,
totally in place of conventional type
cantilever RWs
6)6) Casting-in-place
RC facing
Backfill
Geogrid
Girder
Abutment
Cement-mixed gravelly soil
Bearing
2) 29 GRS bridge abutments,
totally in place of conventional
type bridge abutments
Integrated girder and
a pair of facing
Geogrid
Cement-mixed gravelly soil
Backfill
Firm connection
3) A GRS integral bridge
(1) Box culvert
(2a) Geogrid-reinforced compacted cement-mixed gravelly soil (approach block) (3) Connection concrete
(2b)Backfil
l
4) Three GRS box culvert structures
integrated to GRS RWs
5) Eleven GRS protection
structures at the tunnel entrance
Railway Technical Research InstituteRailway Technical Research Institute
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
57
Railway Technical Research InstituteRailway Technical Research Institute
Type GRS RW
Construction
Mitsui Zosen corp.
Rinkai Nissan corp.
Taisei corp.
Cienco 1(Vietnum)Height 1.8~5.7 m
Length 1,485 m
Date 2013/July
Reinforcement 60 kN/m 93,000㎡Design and
management
Japan Transportation
Consultants
High Speed Railway Projects on Hanoi - Vinh
VietnamHanoi
Vinh
China
Raos
Thai
Cambodia Nha Trang
Ho Chi Minh
58
Railway Technical Research InstituteRailway Technical Research Institute
Railway Technical Research InstituteRailway Technical Research Institute
Contents1. Background (Technical issues around 1990)
6. Overview of recent application
2. Development of GRS retaining wall(1990’s)
60
4. Design of GRS RWs
3. Application of GRS to bridge abutment(2000’s - 2010’s)
5. Advantages of GRS RWs
7. Other examples of GRS structure
Railway Technical Research InstituteRailway Technical Research Institute
Construction on the soft ground or
liquefiable ground
(Cement treated gravelly soil slab)
61
Railway Technical Research InstituteRailway Technical Research Institute
Cement-mixed gravel is often used for
important structure for railway allowing a
limited amount of deformation.
What is Cement-mixed gravel?
After the
construction
Sedimentarytalus
Crystalline
schist
01020304050
3
48
14
16
2650/30
50/23
50/16
Soil backfill
150
1255 Cement-
mixed gravel
Polymer geogridR.L140
100
(Unit in cm)
TokyoTokyo
Kyushu
Shinkansen
GRS bridge abutment
Well-graded gravel with a little volume of cement;
geomaterial in-between soil and concrete.
62
Railway Technical Research InstituteRailway Technical Research Institute
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
63
Railway Technical Research InstituteRailway Technical Research Institute
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 sandstonecement/gravel ratio in weight : 2.5%
geogrid polymer geogrid, tensile strength: 30 kN/m
specimen two rectangular parallelepiped specimens
with geogrid and without geogrid
64
Railway Technical Research InstituteRailway Technical Research Institute
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
65
Railway Technical Research InstituteRailway Technical Research Institute
Application for the actual project (2)Construction of embankment
on liquefiable ground
<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.
slabLiquefiable ground
66
Railway Technical Research InstituteRailway Technical Research Institute
Conclusion
GRS-RW was developed in order to reduce the maintenance cost, land acquisition cost.
This technique was applied to bridge abutment
Full-height rigid facing which is contacted strongly to geosynthetics is the key aspect of this technique.
Cement-mixed gravel slab can be the one of the rational method to construct railway embankment on soft ground. 67
The cost effectiveness of GRS increases when it is applied to the construction
- on soft ground- under heavy axial load- for the high retaining wall- against large natural hazard
Thank you for your attention
The University of Tokyo, JAPAN
(formerly Railway Technical Research Institute, RTRI)
Kenji Watanabewatanabe@civil.t.u-Tokyo.ac.jp
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