3-3

Revised for the graduate school
of the University of Tokyo
Deformation and Strength
Characteristics of Granular Materials:
from experimental research
for the last 35 years by a geotechnical
engineering researcher
III-3
March 29 – April 6, 2005
Paris, France
Tatsuoka, F.
Department of Civil Engineering
Tokyo University of Science
Ageing effect
(Hypo) Elasticity
Plasticity
Viscosity
Shear stress, τ
Non-linear
pre-peak
stress-strain behaviour
Peak strength
Inherent anisotropy
Strain softening
Rate effects
Shear banding with
particle size effects
Dilatancy
Behaviour at small strains
0 Shear strain, γ
(averaged for a specimen)
Pressure-dependency
Non-linear pre-peak stress-strain behaviour:
1.
General; strain-non-linearity and pressurenon-linearity
2.
Shear and compression yielding
mechanisms and the shape of yield loci
3.
Effects of isotropic over-compression and
isotropic sustained loading
4.
Dilatancy
5.
Case history
Case history:
Recent Geotechnical Investigation
for a new long suspension bridge
at Kitan Strait
Akashi
Strait
Bridge
Yura-seto
Bridge
Akashi strait bridge
Topography at the sea bottom
Ａルート
Ｂルート
Yura Seto channel
海底地形測量
海底地形
マルチナロビーム音響測深機
General plan of Yura-Seto Bridge and general ground conditions.
←Awaji Island
Okino shima
Iskand →
Total bridge length: 3,920 m
Central span: 2,150
1,000 m
770 m
3P
2P
1A
4A
Okino
Shima
Island
Awaji
Island
Uncemented Holocene and Pleistocene deposits
Holocene deposit
0m
Osaka group
-50
Holocene deposit
100
Hard rock
100
-200
-250
-250
-300
-50
-150
-150
-200
Terrace deposit
0m
(Izumi formation)
-300
General geological conditions at at the Yura Seto channel
Okino
Shima
Island
Awaji
Island
Uncemented Holocene and Pleistocene deposits
Holocene deposit
0m
Osaka group
-50
Holocene deposit
Terrace deposit
0m
-50
100
100
-150
-150
-200
Hard rock
-250
-250
-300
-200
(Izumi formation)
-300
Ground conditions
Piers 2P & 3P: hard rock (basically no problem)
Anchorage 4A: alternative layers of sandstone and mudstone (hard rock)
(bearing capacity of tunnel anchorage; no serious problem)
Anchorage 1A: alternative layers of uncemented gravel, sand and clay
(as the foundation becomes shallower, the construction cost
decreases, but the estimated settlement of the footing increases)
Izumi group (hard rock)
Pleistocene
Terrace deposit
Upper Osaka group
Lower Osaka group
Where is the relevant compromise between a lower cost (by a
shallower foundation) and a smaller residual settlement (by a
deeper foundation) ?
Altitude (T.P.) (m)
Holocene
Anchorage 1A (route B)
Diaphragm walls
Holocene deposits
Diaphragm walls
Terrace deposit
Pleistocene
deposits
Osaka group (upper)
TP – 71 m
Osaka group (lower)
Currently considered design
Some characteristic geotechnical
engineering issues:
1. Uncemented clay layers exist below a foundation for
a long suspension bridge; the first experience in
Japan.
2. The feasibility of the construction of Anchorage A1,
allowing a limited amount of residual settlement,
depends on the reliability of settlement prediction.
3. A relevant compromise between a lower cost (by a
shallower foundation) and a smaller residual
settlement (by a deeper foundation) should be found.
Detailed site investigation and sampling, 1999 –
2000, at A1 site for route B
No.1; 1999 (dia.= 200 mm)
Investigation in
1998
No. 3;
2000
(dia.= 66 mm)
No. 2:
2000
(dia.= 116 mm)
Investigation in
1999 & 2000
Yura Seto channel
2000 (dia.= 66 mm)
1999 (dia.= 200 mm)
mm)
2000 (dia.= 116
Holocene
Bルート
1A柱状図
About 2 million
years (m.y.)
at the top
Pleistocene
Hard rock
Boring logs
at 1A site,
route B
2000 (dia.= 66 mm)
1999 (dia.= 200 mm)
mm)
2000 (dia.= 116
Pleistocen
e
Bルート
About
20,000
years
1A柱状図
at the top
Terrace
deposit
Osaka group
(upper)
About 0.27 – 0.87
million years
Osaka group
(lower)
About 1.6 million
years at the top:
about 2.64 +- 0.57
million years at
a depth of 160 m
Hard rock
Silty sand to sand & gravel
Clay to silt
Boring logs
at 1A site,
route B
Issues with the Pleistocene deposit - 1
Reliable evaluation of the compressibility (including
consolidation property and viscous property), in
particular, of thin clay layers
a) Very complicated layering, consisting of a number of
alternative relatively thin clay, sand and gravel layers
- How to model the site ?
1A
2P
3P
4A
Uncemented Holocene and Pleistocene deposits
Awaji
Hard rock
(Izumi formation)
Okino
Shima
Island
Issues with the Pleistocene deposit - 2
b) Compressibility of clay layers controls the footing
settlement
- The compressibility of sand & gravel layers; similar* to the
one of the gravel layer supporting pier P2 of Akashi bridge,
which exhibited allowable settlements,
*judged based on the shear wave velocity, dry density and
drained TC stress-strain behaviour.
1A
2P
3P
4A
Uncemented Holocene and Pleistocene deposits
Awaji
Hard rock
(Izumi formation)
Okino
Shima
Island
Issues with the Pleistocene deposit - 3
c) Small strain problem, unlike compression of soft clay
- Stiffness from shear wave velocity; useful ?
d)Undisturbed sampling
- Very difficult with both gravel and clay samples
due to complicated layering
e)Significant bedding error on oedometer tests on stiff clay:
Anisotropic triaxial compression tests using LDTs
f) Usefulness of conventional PMTs ?
1A
2P
3P
4A
Uncemented Holocene and Pleistocene deposits
Awaji
Hard rock
(Izumi formation)
Okino
Shima
Island
BoringNo.
1999 2000 2000
(200mm) (116mm) (66mm)
SPTblowcount
ρt(t/m3)
Water contnet, wn (%)
Altitude Layer
name
1.7
Sampling Sampling Fieldtests
(m)
1.9
2.1
2.3
0 10 20 30 40 50
2.5
Elastic wave velocity (m/sec)
0
1000
Gravel
49.85
-48.7
57.00
-44.1
63.70
-62.5
Clay
66.85
69.60
-65.7
-68.4
Sand
73.75
-72.6
Gravel
80.05
82.65
84.70
-78.9
-81.5
-83.5
92.75
-91.6
99.70
-98.5
Sand
102.60
-101.4
Clay
106.10
-104.9
Gravel
Sand
Clay
Clay
Sand
S-g with
cobbles
Sand
Sand
Holocene
板(3)Down
た た き :hole
H11年
度
(1999)
-20
サ(4)Suspension
ス ペ ン シ ョ ン
(V：)V p
P
サ(5)Suspension
ス ペ ン シ ョ ン
(V：S)V s
-30
-44.1
Sand
Gravel
-21.3
45.30
Sandgravel
Sand
Gravel
22.50
Clay
Gravel
Clay
-16.1
Sandgravel
with
cobbles
Sand
Sandgravel
Sand
17.30
-40
Terrace
Clay
板(2)Down
た た き :hole
H12年
度
(2000)
-10
(2)
SPT blow
count,
N value
-50
-60
Uppper Osaka
Sandgravel
with
cobbles
Sandgravel
with
cobbles
Clay
0
Sandgravel
with
cobbles
(3)
-70
(3)
-80
Sand
Clay
Clay
Fine sand
Sand
Clay
Sand
Clay
113.15
-112.0
Sand
116.53
-115.4
Clay
120.30
-119.1
Hard rock
(sandstone
&
gavelstone
)
138.50
-137.3
Loweest Osaka group
Clay
3000
サ(1)Suspension
ス ペ ン シ ョ ン
:H12
(2000)
年 度
0
Sandgravel
with
cobbles
2000
1.2
Izumi group
Very complicated layering,
consisting of a number of
alternative relatively thin
clay, sand and gravel
layers
Depth
Total unit weight
-90
Undisturbed
samples
(2)
wn (%)
(4)
-100
(1)
-110
-120
密度
In-situloggin
w検
ith層
Field
bamma ray
density室内土質
-130
logging
試験
-140
(5)
Vs
VP
“Undisturbed” sampling along route B
Clay: dia.= 116 mm
SAND & gravel: dia.= 20 mm
A sufficient amount of sample could not been retrieved from
many thin clay layers by 200 mm-dia. RCT sampling, while
sand and gravel samples were difficult to retrieve by 116
mm-dia. thin wall tube sampling.
Silty sand to sand & gravel
Boring log (1)
試験結果深度分布図(1)
Total unit weight
湿潤密度ρｔ
(gf/cm3)
調査孔（各々5.0m離れ）
H11年 H12年 H12年
200mm 116mm 66mm
サンプ
リング
サンプ
標
高
原位置
リング
試験
About
20,000
years1.2
at the top
Terrace
deposit
Clay to silt
地
層
名
1.7
1.9
2.1
砂質土
0
10
20
30
40
-10
-62.5
中
丘
位
層
段
-81.5
大
上
阪
部
層
層
群
礫質土
砂質土
粘性土
砂質土
玉石混り
砂礫
粘性土
砂質土
粘性土
砂岩,
礫岩
-137.3
Down hole (1999)
P wave by suspension (2000)
サ ス ペ ン シ ョ ン ： Vs
S wave by suspension (2000)
-70
-80
Water content (%)
密度検層
Gamma
ray
室内土質
Undisturbe
試験
d samples
-140
3000
Down hole (2000)
-60
-130
2000
板 た た き :H11年 度
-90
和
泉
層
群
1000
(2000)
-50
-120
0
サ ス ペ ン シ ョ ン ： Vp
Osaka group
最大
(lower)下 阪 -100
層
About 部
1.6
群 million
層
-110
years at the top:
-119.1
50
板 た た き :H12年 度
-48.7
粘性土
Elastic wave velocity
弾性波速度(m/sec)
(m/sec)
サ ス ペ ン シ ョ ン :H12年
Average for suspension
度
Blow
count
s
Osaka 沖
group-20
積
(upper)層
About 0.27 –-300.87
million years-40
砂礫
2.5
0
粘性土
玉石混り
2.3
Water content (%)
含水比、N値
and
SPT blow counts
Ｎ 値
自 然 含 水 比
Silty sand to sand & gravel
Boring log (1)
試験結果深度分布図(1)
Total unit weight
湿潤密度ρｔ
(gf/cm3)
調査孔（各々5.0m離れ）
H11年 H12年 H12年
200mm 116mm 66mm
サンプ
リング
サンプ
標
高
原位置
リング
試験
About
20,000
years1.2
at the top
Terrace
deposit
Clay to silt
地
層
名
1.7
1.9
2.1
砂質土
0
10
20
30
40
-10
Elastic wave velocity
弾性波速度(m/sec)
(m/sec)
50
0
1000
2000
(2000)
板 た た き :H12年 度
Down hole (2000)
板 た た き :H11年 度
Down hole (1999)
サ ス ペ ン シ ョ ン ： Vp
P wave by suspension (2000)
サ ス ペ ン シ ョ ン ： Vs
S wave by suspension (2000)
-48.7
-62.5
中
丘
位
層
段
-81.5
大
上
阪
部
層
層
群
粘性土
礫質土
砂質土
粘性土
砂質土
玉石混り
砂礫
粘性土
砂質土
粘性土
-50
-60
-70
-80
-90
Osaka group
最大
(lower)下 阪 -100
層
About 部
1.6
群 million
層
-110
years at the top:
-120
-119.1
砂岩,
礫岩
-137.3
和
泉
層
群
Water content (%)
The density and Vs generally increase with depth,
but no clear discontinuity at a depth of 82 m,
despite a clear discontinuity in the geological age.
密度検層
Gamma
ray
-130
室内土質
Undisturbe
試験
d samples
-140
3000
サ ス ペ ン シ ョ ン :H12年
Average for suspension
度
Blow
count
s
Osaka 沖
group-20
積
(upper)層
About 0.27 –-300.87
million years-40
砂礫
2.5
0
粘性土
玉石混り
2.3
Water content (%)
含水比、N値
and
SPT blow counts
Ｎ 値
自 然 含 水 比
Ｐｃ(kN/m
)
Oedometer
yield stress2(kPa)
0
2000
4000
6000
8000
定ひずみ速度載荷圧密試験
Terrace deposit:
about 20,000 years at the top
CRS
oedometer (strain rate=
（ 0.01∼ 0.05%/min)
0.01
–
0.05 %/min.)
三 軸 圧 密 試 験 （ 0.002%/min)
Triaxial compression
(strain
有 効rate=
土 被 0.002
り 圧 （%/min.)
σ ov'）
In-situ effective overburden
O.C.R=1.2
pressure
OCR= 1.2
O.C.R=2.2
OCR= 2.2
O.C.R= 6.0
OCR= 8.0
48.7 m
Upper Osaka group;
about 0.27 –
0.87 million years
62.5 m
2)
Young’s
modulus stress (MPa)
Ｅ(MN/m
0
1000
2000
3000
4000
Ef: Suspension seismic survey
ＰＳ検層
EPMT.PB: Pre-bored PMTs (monotonic loading)
水平載荷試験
5000
0
-10
EPMT.SB: Self-bored PMTs (cyclic loading)
水平載荷（セルフボーリングタイプ）
E0: Triaxial tests using LDTs
-20
三軸圧縮試験(LDT)より求まる微小ひずみ時のＥ
(at axial strains less than 0.001 %)
-30
-40
-50
-60
-70
81.5 m
Lowest Osaka group:
about 1.6 million years at the top and
more that 2.60 million years at the bottom
-80
-90
-100
-110
119.1 m
-120
-130
-140
1) E0 from triaxial tests using LDTs; consistent with Ef from Vs.
2) Pre-bored PMTs tests; very low stiffness and no discontinuity at a depth of
82 m (not very useful in this project).
3) Self-bored PMTs: much larger stiffness, but too time-consuming test !
Ｐｃ(kN/m
)
Oedometer
yield stress2(kPa)
0
2000
4000
6000
8000
定ひずみ速度載荷圧密試験
Terrace deposit:
about 20,000 years at the top
CRS
oedometer (strain rate=
（ 0.01∼ 0.05%/min)
0.01
–
0.05 %/min.)
三 軸 圧 密 試 験 （ 0.002%/min)
Triaxial compression
(strain
有 効rate=
土 被 0.002
り 圧 （%/min.)
σ ov'）
In-situ effective overburden
O.C.R=1.2
pressure
OCR= 1.2
2)
Young’s
modulus stress (MPa)
Ｅ(MN/m
0
1000
2000
3000
Ef: Suspension seismic survey
ＰＳ検層
EPMT.PB: Pre-bored PMTs (monotonic loading)
水平載荷試験
5000
0
-10
EPMT.SB: Self-bored PMTs (cyclic loading)
水平載荷（セルフボーリングタイプ）
E0: Triaxial tests using LDTs
-20
三軸圧縮試験(LDT)より求まる微小ひずみ時のＥ
(at axial strains less than 0.001 %)
O.C.R=2.2
OCR= 2.2
O.C.R= 6.0
OCR= 8.0
48.7 m
Upper Osaka group;
about 0.27 –
0.87 million years
4000
62.5 m
-30
-40
-50
-60
-70
81.5 m
Lowest Osaka group:
about 1.6 million years at the top and
more that 2.60 million years at the bottom
-80
-90
-100
-110
119.1 m
-120
-130
-140
A very clear discontinuity at a depth of 82 m in the yield pressure
from1D compression tests and K0-triaxial compression tests.
- consistent with a clear discontinuity in the geological age;
- inconsistent with the distribution of density and Vs with depth.
Pc付近の間隙水圧/軸圧縮圧力
∆u / σ v = 0.3 – 5 % around the
0.3∼5.0％、平均2.2％
yield stress
One-dimensional CRS compression tests
圧密圧力-軸ひずみ：中位段丘層
and K0 TC tests
調 査 孔 （ 各 々 5 .0 m 離 れ ）
H 11年
H 12年
2 0 0 mm 1 1 6 mm
サンプ
リング
サンプ
リング
H 12年
6 6 mm
原位置
試験
標
高
地
層
名
Vertical
stress (kPa)
圧密圧力（kN/m2)
1 .2
10
100
1000
0.0
About 20,000 years
at the top
Terrace
deposit
玉石混り
砂礫
沖
積
層
砂質土
-48.7
-62.5
中
丘
位
層
段
-81.5
大
上
阪
部
層
層
群
粘性土
礫質土
砂質土
粘性土
砂質土
玉石混り
砂礫
TC (strain rate=
0.002 %/min.)
1.0
Vertical
strain (%)
軸ひずみ（εa）%
粘性土
2.0
3.0
4.0
5.0
6.0
7.0
Data points:
8.0
CRS oedometer (strain rate=
粘性土
最
下
部
層
砂質土
粘性土
大
阪
層
群
10.0
-119.1
砂岩,
礫岩
-137.3
9.0
実線 三軸圧密(LDT)
点 定ひずみ圧密
0.01 –
0.05 %/min.)
和
泉
層
群
定ひずみ圧密と三軸圧密(LDT)
軸ひずみ（εａ)∼圧密圧力の比較:中位段丘層（粘性
土）
10000
0
Anisotropic TC
(external)
5
Significant effects of BE in
oedometer tests
CRS oedimenter
10
Osaka group (upper)
Specimen No.21
（TP -64.22m）
15
20
10
100
1000
10000
2
Effective vertical stress, σ'v (kN/m )
Anisotropic TC
(LDT)
0
Vertical strain, ε a (%)
Vertical strain, ε a (%)
Anisotropic TC
(LDT)
Anostrpopic TC
(external)
部変
5
CRS oedometer
10
15
Osaka group (lower)
Specimens No. 44 & 45
(TP -86.99m)
20
10
100
1000
10000
Effective vertical stress, σ'a (kN/m2)
100000
One-dimensional CRS compression tests and Pc付近の間隙水圧/軸圧縮圧力
∆u / σ v = 1.1 –7.4 % around
圧密圧力-軸ひずみ：大阪層群上部層
1.1∼7.4％、平均3.5％
K0 TC tests
the yield stress
Vertical
stress (kPa)
圧密圧力（kN/m2)
調 査 孔 （ 各 々 5 .0 m離 れ ）
H 12年
H 11年
2 0 0 mm 1 1 6 mm
H 12年
6 6 mm
サンプ
サンプ
原位置
リング
リング
試験
標
高
地
層
名
10
100
0.0
1 .2
砂質土
-48.7
-62.5
中
丘
位
層
段
-81.5
大
上
阪
部
層
層
群
粘性土
礫質土
砂質土
粘性土
砂質土
玉石混り
砂礫
軸ひずみ（εa）%
砂礫
Vertical strain (%)
Osaka group
沖
積
(upper)
層
About 0.27 – 0.87
million years
玉石混り
2.0
3.0
4.0
5.0
6.0
7.0
Data points:
8.0
CRS oedometer (strain rate=
粘性土
最
下
部
層
砂質土
粘性土
大
阪
層
群
礫岩
-137.3
9.0
実線 三軸圧密(LDT)
0.01 点 定ひずみ圧密
– 0.05 %/min.)
10.0
-119.1
砂岩,
10000
TC (strain rate=
0.002 %/min.)
1.0
粘性土
1000
和
泉
層
群
定ひずみ圧密と三軸圧密(LDT)
軸ひずみ（εａ)∼圧密圧力の比較：大阪層群上部層
Pc付近の
One-dimensional
CRS
compression
tests
and
間隙水圧/軸圧縮圧力
圧密圧力-軸ひずみ：大阪層群最下部層（上部）
∆
u
/
σ
=
0.0
– 4.2
% around
v
K0 TC tests
0.0∼4.2％
the yield平均1.5
stress4％
調 査 孔 （ 各 々 5 .0 m 離 れ ）
H 12年
H 11年
2 0 0 mm 1 1 6 mm
サンプ
リング
サンプ
リング
H 12年
6 6 mm
原位置
試験
標
高
1 .2
Vertical
stress (kPa)
圧密圧力（kN/m2)
地
層
名
10
100
1000
0.0
砂質土
-48.7
-62.5
中
丘
位
層
段
-81.5
大
上
阪
部
層
層
群
粘性土
礫質土
砂質土
粘性土
砂質土
玉石混り
砂礫
粘性土
砂質土
粘性土
砂岩,
礫岩
最
下
部
層
大
阪
層
群
Vertical strain (%)
沖
積
層
砂礫
軸ひずみ（εa）%
玉石混り
TC (strain rate=
0.002 %/min.)
1.0
粘性土
10000
2.0
3.0
4.0
5.0
6.0
7.0
8.0
Data points:
実線 三軸圧密(LDT)
CRS
oedometer (strain rate=
点 定ひずみ圧密
0.01 – 0.05 %/min.)
Upper layers of
9.0
Osaka group
-119.1
(lower)
10.0
和
定ひずみ圧密と三軸圧密(LDT))
泉 1.6 million
About
層
軸ひずみ（εａ)∼圧密圧力の比較：大阪層群最下部
群 at the top:
- 1 3 7 .years
3
層（上位）
圧密圧力-軸ひずみ：大阪層群最下部層（下部）
One-dimensional
CRS compression tests and K0 TC tests
Vertical
stress (kPa)
圧密圧力（kN/m2)
調 査 孔 （ 各 々 5 .0 m離 れ ）
H 12年
H 11年
2 0 0 mm 1 1 6 mm
H 12年
6 6 mm
サンプ
サンプ
原位置
リング
リング
試験
標
高
地
層
名
10
1 .2
100
0.0
1000
10000
TC (strain rate=
0.002 %/min.)
1.0
粘性土
沖
積
層
砂礫
砂質土
-48.7
-62.5
中
丘
位
層
段
-81.5
大
上
阪
部
層
層
群
粘性土
礫質土
砂質土
粘性土
砂質土
玉石混り
砂礫
2.0
Vertical
strain (%)
軸ひずみ（εa）%
玉石混り
3.0
4.0
5.0
6.0
7.0
8.0
Data points:
実線 三軸圧密(LDT)
CRS oedometer
(strain rate=
点 定ひずみ圧密
9.0
0.01 – 0.05 %/min.)
粘性土
砂質土
粘性土
砂岩,
礫岩
最
下
部
層
大
阪
層
群
Lower layers of
Osaka group
-119.1
(lower)
和
泉 million
About 1.6
層
years
- 1 3 7 . 3 at群the top:
10.0
定ひずみ圧密と三軸圧密(LDT)
軸ひずみ（εａ)∼圧密圧力の比較：大阪層群最下部
層（下位）
Anisotropic
triaxial compression tests using LDTs
圧密圧力-軸ひずみ：粘土層集積（LDT）
Vertical
stress (kPa)
圧密圧力（kN/m2)
調 査 孔 （ 各 々 5 .0 m 離 れ ）
H 12年
H 11年
2 0 0 mm 1 1 6 mm
H 12年
6 6 mm
サンプ
サンプ
原位置
リング
リング
試験
標
高
地
層
名
10
100
1000
0
1 .2
粘性土
玉石混り
沖
積
層
砂質土
-48.7
-62.5
中
丘
位
層
段
-81.5
大
上
阪
部
層
層
群
粘性土
礫質土
砂質土
粘性土
砂質土
玉石混り
砂礫
1
Vertical
strain (%)
軸ひずみ εa (%)
砂礫
2
3
粘性土
最
下
部
層
砂質土
粘性土
大
阪
層
群
4
-119.1
砂岩,
礫岩
-137.3
和
泉
層
群
5
Depth (m)
標高：-51.6 中位段丘層
-51: 標高：-64.2
Terrace 大阪層群上部層
deposit
-64.2: 標高：-64.5
Osaka group
(upper)
大阪層群上部層
-75.2: 標高：-75.2
- 大阪層群上部層
大阪層群最下部層（上位）
-87.8: 標高：-87.8
Osaka group
(lower)
-103.5:標高：-103.5
- 大阪層群最下部層(下位）
10000
3000
Correlation between E0 from TC tests
and py from the oedometer tests
●: measured E0 and inter-polated py
○: inter-polated E0 and measured py
TP-104.3m
2
Eo (MN/m )
2000
TP-85.5m
1000
TP-67.1m
TP-71.2m
TP-75.2m
TP-66.6m
TP-51.6m
0
0
2000
4000
6000
8000
2
py (kN/m )
a) A good correlation inside the upper Osaka group
b) A clear discontinuous between the data for upper and lower
Osaka groups.
Correlation between Ef from field shear wave velocity and
圧密降伏応力と変形係数の相関（２）
py from the oedometer tests
2500
Relation for
depth= -75.2 m or less
2
Inter-polated Ef (MN/m )
3000
2000
1500
depth= -75.2 m
1000
Depth= 84.5 m or more
TP-51.8m
500
0
0
2000
4000
6000
8000
10000
2
Measured py (kN/m )
a) A good correlation inside the upper Osaka group
b) A clear discontinuous between the data for upper and lower
Osaka groups.
Terrace deposit
Osaka group (upper)
Osaka group (lower)
降伏前の圧縮指数1/Cs
l/”C
c before yielding from
TC tests using LDTs”
140
120
100
中位
段丘層
大阪層群
最下部層
大阪層群
上部層
80
60
The Osaka group (lower):
1) No particularly large pre-yield stiffness
2) A high yield stress
40
20
0
0
2000
4000
6000
8000
Oedometer yield stress, py (kPa)
10000
Schematic diagram
Stress
Elastic deformation property:
no distinct discontinuity between
Osaka groups upper and lower
Osaka group (lower)
Yield stress: increased by mechanical
over-consolidation ?
Osaka group (upper)
Yield stress
0
Strain
Depth
Triaxial compression tests on
undisturbed samples of clay
0
(m)
sandbar
40
0m
Alluvium
Terrace
deposit
No.19
No.20
64
65
No.38
No.44
86
88
60
Osaka group
(Pleistocene)
100m
Hard Rock
200m
80
100
(m)
Depth of clay samples
Sample No.
Sampleing
Depth
ρt g/cm3
ρd g/cm3
ρs g/cm3
wn %
e
Sr %
No.19
No.20
No.38
No.44
64.68m
65.02m
85.78m
88.07m
∼65.02m ∼65.34m ∼86.28m ∼88.72m
2.009
1.611
2.705
24.7
0.679
98.4
1.901
1.439
2.693
32.1
0.871
99.2
1.926
1.492
2.627
29.1
0.761
100.5
2.065
1.700
2.678
21.5
0.576
100.0
2∼75mm %
75 μm∼2mm %
5∼75 μm %
under 5 μm %
Uc
Uc'
mm
D50 mm
0.0
42.9
23.3
33.8
*
*
2.000
0.0303
0.0
8.3
37.1
54.6
*
*
0.425
0.0034
0.0
3.1
43.4
53.5
*
*
0.250
0.0042
0.0
1.5
64.3
34.2
*
*
0.106
0.0101
wL %
wp %
Ip
31.9
10.3
21.6
54.7
13.6
41.1
86.1
24.0
62.1
70.3
26.2
44.1
Clay
CLS
Clay
CH-S
Clay
CH
Silt
MH
500
Kitan Clay No.19
CD TC
Depth= 64.9m
σ'h= 340 kPa
Deviator Stress, q (kPa)
400
1/5
1/5
0
0.0
1200
1000
Creep (12h)
1/5
Reconstituted (ec= 0.82)
(dεv/dt)0= 0.0042 %/m
1/10
10?
Axial strain, εv (%)
0.5
1.0
1.5
2.0
No.19
No.20
64
65
No.38
No.44
86
88
60
Osaka group
(Pleistocene)
100m
Hard Rock
200m
80
Undisturbed (ec= 0.61)
(dεv/dt)0= 0.0033 %/m
Kitan Clay No.44
CDTC Test
Depth= 88 m
σ'h= 470 kPa
100
The other changes in the strain rate:
10 times & 1/10 times
100
1/100
400
εvol (%)
Alluvium
100
(m)
600 1/100
0
10.0
2
3
4
0m
Terrace
deposit
5
1/5
800
200
40
1/5
2
1400
0
(m)
sandbar
1
1600
Depth
1/5
Creep
(24h)
1/5
Creep
(12h)
200
εvolume (%)
1/5
1/5
300
100
Daviator Stress, q (kPa)
Undistrubend (ec= 1.03)
(dεv/dt)0= 0.0076 %/m
1/5
1/10
Reconstituted (ec= 0.79)
(dεv/dt)0= 0.0037 %/m
1/5
0.5
1.0
5
10
5
20
1/50
Axial strain, εv (%)
1.5
2.0
Difference in the stress-strain
behaviour between the undisturbed
sample and reconstituted specimen;
-increases with the sampling depth,
in particular, suddenly at d= 82 m,
due to largely increased ageing
2.5
effects.
Summary
Between the upper and lower Osaka group deposits:
1) A large discontinuity in the geological age (0.87 versus 1.6
million years).
2) No clear discontinuity in Vs (by both down-hole and
suspension methods) and E0.
3) No clear discontinuity in the stiffness from pre-bored PMTs*.
*: very low compared to the small strain stiffness.
4) A clear discontinuity in the yield pressure from oedometer
tests and anisotropic TC tests.
- A discontinuity in the linearity in the stress-strain relations.
5) Large BE in the strains in oedometer tests
Viscous property of clay
Summary
Between upper and lower Osaka group deposits:
1) A large discontinuity in the geological age (0.87 versus 1.6
million years).
2) No clear discontinuity in Vs (by both down-hole and
suspension methods) and E0.
3) No clear discontinuity in the stiffness from pre-bored PMTs*.
*: very low compared to the small strain stiffness.
4) A clear discontinuity in the yield pressure from oedometer
tests and anisotropic TC tests.
- A discontinuity in the linearity in the stress-strain relations.
5) Large BE in the strains in oedometer tests
Viscous property of clay
Preliminary estimate of the settlement of A1
One-dimensional accounting for pressure spreading
1) Sand and gravel layers: drainage layers
2) Estimate using the coefficients of secondary consolidation
(ignoring the effects of stress history)
Anchorage 1A (route B)
Diaphragm walls
Holocene deposits
Diaphragm walls
Terrace deposit
Pleistocene
deposits
Osaka group (upper)
Osaka group (lower)
TP – 71 m
5.0
Anisotropic TC tests
with intermediate drained
creep loading stages
Anisotropic TC (LDT)
Specimen No.54-2 (TP -103.48 m)
4000
3000
3.0
σv'
2000
2.0
1000
1.0
εa(LDT)
0
0
2000
4000
6000
8000
Elapsed time, t (min)
0
Vertical strain, εv (%)
0.5
1
Anisotropic TC
(creep loading during otherwise
CRS ML)
Specimen No.54-2
(TP -103.48m)
1.5
2
10
100
4.0
1000
Effevtive vertical stress, σ'v
10000
2
(kN/m )
10000
12000
0.0
14000
Vertical strain,εv (%)
2
Effective vertical stress, σv' (kN/m )
5000
Coefficient of secondary consolidation, Cαε (%)
0.50
T errac e d ep o s it
0.45
0.40
0.35
0.30
0.25
0.20
0.15
Lo wes t O s aka gro up
0.10
Up p er O s aka gro up
0.05
0.00
500
600
700
800
900
1000
1100
1200
1300
1400
1500
2
Effec tive vertic al s tres s , σ v '（ kＮ /m )
Coefficient of secondary consolidation:
∆ε creep = Cα ⋅ log10 (t / t0 )
t0: time at the end of primary consolidation in
the standard oedometer test.
Anchorage 1A (route B)
Summary of
settlement prediction
Diaphragm walls
Diaphragm walls
Holocene deposits
Terrace deposit
Pleistocene
deposits
TP – 71 m
Osaka group (upper)
Osaka group (lower)
Primary
Secondary
ｔ= 30 yrs
t= 50 yrs
Upper Osaka
group
0.6 cm
1.27 cm
1.33 cm
Lower Osaka
group
2.4
6.3
6.8
Total
3.0
7.6
8.1
Time history of settlement by preliminary analysis
(1.0)
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
11.0
12.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
600.0
計算データ、Mv：三軸圧密（LDT)、Cv：定ひずみ速度圧密、Cαε：長期圧密試験
400.0
Anticipated average contact pressure
at the bottom of foundation
0.6
1.7
200.0
0.0
1.2
-200.0
2.1
Primary settlement
3.6
-400.0
5.0
-600.0
7.3
7.9
一次元圧密計算＋長期圧密沈下計算（Cαε）
Total一次元圧密計算
settlement:
primary
+ secondary
増加荷重（連壁先端-71.0m)
-800.0
-1000.0
-1200.0
ここでの長期圧密計算は前の荷重履歴を考慮していない近似計算であり、一次圧密90%終了時から増加荷重（荷重分散
30°）に対応したCαεを用いて計算した値
Not very large settlement, due to:
a) a smaller contact pressure, relative to the Akashi strait
bridge; and
b) relatively thin and old clay deposits.
増加荷重ΔＰ（kN/m2)
Settlement
(cm)
沈下量（ｃｍ）
0.0
(6.0)
(5.0)
(4.0)
(3.0)
(2.0)
Average contact pressure (kN/m2)
Elapsed
time (years)
経過時間（年）
Time-dependent settlement behaviour
of the foundations for Akashi Strait
Bridge
14th Oct. 1989
End of tower construction
6
4
2
0
4
2
Settlement,
S (mm)
-10
-40
Settlement,
S(mm)
End of tower construction
0
-20
The 1995 Hygo-ken Nambu Earthquake
-60
-80
-100
-140
6
0
10
-2
0
-120
26th Jan. 1990
2
8
8
(p)ave (kgf/cm )
2
10
Applied pressure,
10
(p)ave(kgf/cm )
Applied pressure,
12
a)
-20
-30
-50
2P
500
b)
3P
-60
-70
0
The 1995 Hyogo-ken Nambu
earthquake
-40
1000
1500
2000
Elasped time (days)
2500
3000
3500
0
250
500
750
1000
1250
Elasped time (days)
1500
1750
2000
Anchorage 1A
Then, how shallower the
foundation could be made ?
(route B)
Holocene
Diaphragm walls
Terrace deposit
Pleistocene
Osaka group (upper)
Osaka group (lower)
TP – 71 m