structures on and within man-made deposits...

1

Structures on and within Man-made Deposits - Kansai International Airport -

Osaka University

Kazuhiro ODA

Structures on and within Man-made Deposits - Kansai Airport - Outline of Kansai International Airport Geotechnical Problems

– Residual large-scale settlement– Differential settlement– Residual lateral displacement

Recent topics– Numerical model on upper Pleistocene clays of

Osaka Bay– Spatial estimation of soil properties





JAPAN

Tokyo

Osaka

OSAKA UNIVERSITY

Location of Osaka• Kansai International

Airport is the only international airport in Osaka.

• Osaka is second largest city in Japan.

• It is a center of the western side of Japan in the economical and social activity

2

OSAKA UNIVERSITY

Osaka Bay

Osaka

Kyoto

Kobe Nara

Osaka Bay

• The city of Osaka faces the Osaka Bay

• The Osaka Bay is an inland bay formed in the Osaka Basin surrounded by mountainous regions with rock bed

• The present shape of the Osaka Bay is like an ellipse having the long axis in the direction of north-east to south-west.

• The size is about 60km of the long axis and about 30km of the short one, and about 1500km2 of the area.

Osaka Univ.

Transition of Land Reclamation (Before Edo era)

Reclaimed lands in Osaka Bay

Kansai International Airport

LEGEND

Before modern ages1868-19241925-19451946-1994Under construction or planning

OSAKA UNIVERSITY

• The history of developing the Osaka Bay can go back to the ancient time, and in the Edo era (1603-1867)

• New land development in the estuary of big rivers had been carried out for rice fields.

Transition of Land Reclamation (Meiji Era)



LEGEND


OSAKA UNIVERSITY

• Since the Meiji era (1868-1911), land development due to reclamation along coastal area was rapidly extended for the harbor facilities and industrial site.

Transition of Land Reclamation (After World War II)



LEGEND


OSAKA UNIVERSITY

• After the World War Ⅱ, a trend of land development has been turned from the reclamations along costal area into the construction of off-shore man-made islands.

3

Transition of Land ReclamationReclaimed lands in Osaka Bay


LEGEND


OSAKA UNIVERSITY

• These islands had been constructed on very soft seabed deposits with water depth of over 10m at offshore.

• Therefore, the occurrence of various kinds of geotechnical problems concerned with the soft clay deposits was forecasted, and their countermeasures were examined.


OSAKA UNIVERSITY

• Area of the airport island of the 1st Phase is 510ha. That of the 2nd Phase is 545ha.

• The Kansai international airport has two runways. The one is Runway A in 3,500m long, the other is Runway B in 4000m in long.

• Kansai international airport is the only airport operating for 24 hours.

History of Kansai International Airport

OSAKA UNIVERSITY

• 1987: Start of construction of the airport island of the 1st Phase

• 1991: Completion of construction of the airport island of the 1st Phase

• 1994: Opening of the Kansai International Airport

History of Kansai International Airport

OSAKA UNIVERSITY

• 1999: Start of construction of the airport island of the 2nd Phase

• 2005: Completion of construction of the airport island of the 2nd Phase

• 2007: Start of operation of Runway B

4

Geological profile of seabed at airport site

OSAKA UNIVERSITY

• The geological formation is inclined toward offshore, while comparatively homogeneous along the shoreline.

• The uppermost Holocene clay layer is almost normally consolidated. thickness is from 18m to 24m.

Geological profile of seabed at airport site

OSAKA UNIVERSITY

• The underlain Pleistocene deposits are the over-consolidated clay layers (Ma: marine clay, Dtc and Doc: non-marine clays) with about 1.3 of OCR and the sand and gravel thin layers. These layers alternately deposit in the total thickness of several hundreds meters.

Overburden pressure due to construction

The conventional reclaimed land load

20 - 30 tf/m2

The KIA island load1st phase 45-50 tf/m2

2nd phase 55-60 tf/m2

The pressure is affected more deeper position in case of Kansai International Airpot

Water Depth

LEGEND


Reclaimed land in Osaka Bay





5

50

100

150

200

250

300

350

400

0

Dep

thB

elow

Sea

Lev

el(m

) Ma-12Ma-11a

Ma-10

Ma-9

Ma-7

Ma-3

Ma-13Ds-1

Ma-8

Ds-10

Ma-2

Ma-1

Ma-0

Kansai

Improved bySand Drain

Sand Drain Method Dia. = 40 cm

Holocene Deposit

Plei

stoc

ene

Dep

osits

Thickness is about 20 m

OSAKA UNIVERSITY

The Holoceneclay layer is improved by sand drains, before reclamation.

However, the Pleisticenelayers could not be improved.

Settlement of the 1st phase island

0

500

0 1000 2000 3000 4000 5000 6000

Overbur

den

Pressure

(kPa

)

Elapsed Time (Day)

0

5

10

15

Settlem

ent

(m

)

Total Settlement

Pleistocene Layers

Holocene Layer(Improved by Sand Drain)

Open the Airport Sep. 1994

OSAKA UNIVERSITY

The settlement of Holocene clay layer had already finished.

The residual large-scale settlement occurs mainly in the thick Pleistocene clay layers

Variation of Measured Settlement at Ground Level of the KIAI (Phase I)

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04

Time (Day)

Set

tlem

ent

(m)

0 1000 2000 3000 4000 5000 6000

1-4-A1-5-A1-6-A1-7-A

○ 1-4-A

△ 1-5-A

□ 1-6-A

× 1-7-A

• Residual settlement behaviors are different in the airport island.

• Settlements in 1-4-A is greater than those in 1-7-A.

• Holocene and Pleistocene clay layers in 1-4-A are those in 1-7-A.

Off shore

Settlement Rate of Ground Surface

0

10

20

30

40

50

60

70

80

Year

Settl

emen

t rat

e（ｃｍ

／ye

ar）

● Average of 17 positions

Yearly reduction of settlement rate　　4cm/year

3cm/year

1994 1995 1996 1997 1998 1999 20012000 2002

OSAKA UNIVERSITY

• Distinguishing consolidation characteristics of Pleistocene clay make difficult to predict of settlement.

• The settlement rate will decrease gradually.

• The rate becomes about 7cm/year in 2013.

• The consolidation settlement will continueafter 2014.

• It is very important to predict the settlement in the future, because of maintenance of KIA.

6

Countermeasure against Residual large-scale settlement

Prediction of long-term consolidation behavior of Pleistocene clay layers– To elucidate the distinguishing consolidation

characteristics of Pleistocene clays– Numerical modeling of these consolidation behavior– Configuration of sand or sandy gravel layers– Estimation of sand or sandy gravel layers as drainage

paths– Etc.





Runway

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0 500 1000 1500 2000 2500 3000

Distance (m)

Rela

tive

Sett

lem

ent(

m)

Differential Settlement of the Runway

60cm

Domestic cargoterminal

Fuel tanksSupply anddisposal zone

Internationalcargo terminal

Control towerAero plaza

Railway station Passenger terminalbuildings (PTB)

Ferry terminalMentenancezone

Oil tanker berth Runway (3,500m×60m) To access bridgeA

A

OSAKA UNIVERSITY

Maximum differential settlement of Runway is about 60 cm. The differential settlement is not so much without any troubles of landing and taking off, because of the ground improvement due to vibro-tamping.

Differential Settlements of the Passenger Terminal Building

OSAKA UNIVERSITY

The passenger terminal building was designed by a italian designer.It is not so strong for differential settlement.

7

Plane View of the Terminal Building

about 1,600 m

OSAKA UNIVERSITY

The passenger terminal building was rested directly on the fill material without piles.

about 1,600 m

Accumulated Relative Settlement

-2000

-1500

-1000

-500

0

0 200 400 600 800 1000 1200 1400 1600

Length （ｍ）

Sett

lem

ent

（m

m）

0.40%

-0.13%

OSAKA UNIVERSITY

The differential settlement occurred with the maximum gradientof about 0.40%, mainly due to the uneven surcharge load.The maximum gradient was more than the critical value of 0.2%.

Countermeasures against Differential Settlement of the Building

The jacking up system was applied to the bottom of groundfloor of the terminal building to adjust the differential settlement

Hydraulicjack

Filler plates

Pillar

Outline of Jacking up system

Cross-section of PTB

OSAKA UNIVERSITY

Manual Jack-up under Operation

OSAKA UNIVERSITY

Number of pillars is about 1,000.

8

-2000

-1500

-1000

-500

0

0 200 400 600 800 1000 1200 1400 1600

Length （ｍ）

Sett

lem

ent（

mm

）

After Juck up

Before Juck Up

Jack Up

As of Dec. 2001

Terminal Building

0.18%

OSAKA UNIVERSITY

Differential settlement curves before andafter the jacking-up

The gradient is reduced to 0.18%It is less than the critical value.





Mechanism of lateral residual settlement

Lateral Displacement

Settlement

Gradient of Settlement

Lateral Displacement

Caisson

Seabed Surface

Settlement

Ground Surface

Settlement

Gradient of Settlement

• The distributions of lateraldisplacement and gradient ofsettlement are very similar.

• The residual lateral displacementof the reclaimed deposits iscaused by the residual differentialsettlement of seabed soft layer.

Lateral Deformation around Seawalls in Kansai International Airport

Lateral displacement (cm)toward sea

930days

738days

152days

336days

AC

Reclaim

ed soil

Dep

th (m

)

toward inland The lateral displacement occurs as the rotational deformation around a position on the uppermost surface of Pleistocene layers.

9

Lateral Displacement of Seawalls in KIAI (phase I)

0.0

0.5

1.0

1.5

2.0

2.5

1993/12 1994/12 1995/12 1996/12 1997/12 1998/12 1999/12 2000/12 2001/12 2002/12 2003/12

late

ral d

ispl

acem

ent（ｍ

）

① ② ③

④ ⑤ ⑥

② ①

⑥⑤④

③①②

③

④ ⑤⑥

③①②

⑥⑤

④

All data show the time-dependent lateral displacement of 1～2mat maximum toward inland.

Example of Countermeasure against Lateral Displacement

Bent pipe

Bent pipelines on bridge to oil tanker berthOSAKA UNIVERSITY

• The best countermeasureagainst the lateraldisplacement is not toconstruct any importantfacilities within the affectedzone, which is withinabout 70m from theseawall.

• The pipelines connecting with tanker berth were bentto avoid the affect oflateral displacement ofseawall.

Countermeasure against differential settlement and lateral displacement

Prediction of residual settlement at arbitrary position in inland.– Accurate estimation of the history of reclamation– Spatial estimation of soil properties.– Etc.



Recent topics– Numerical modeling on upper Pleistocene clays of


10

Consolidation characteristics of Pleistocene clays of Osaka Bay

The Pleistocene clays of Osaka Bay have the consolidation yield stresses, pc, higher than the current overburden pressure, p0, although the clays have never been applied higher pressure than the current overburden pressure, p0, judging from the geological findings.

In that sense, Pleistocene clays of Osaka Bay have been called as “quasi-overconsolidated clays”.

The mechanical characteristics of the quasi-overconsolidated clays are quite distinctive from those of mechanically overconsolidated clays due to loading/unloading history.

Long-term consolidation characteristics of Quasi-overconsolidated clay

18

15

12

9

6

3

0

1x10-2 1x10-1 1x100 1x101 1x102 1x103 1x104 1x105

Ver

tical

stra

in (%

)

Elapsed time (min)

Ma10 at Kansai international airport

p0 : 870kPa

pc : 1294kPa

A significant delayed compression occurs after end of primary consolidation even in the range of stress lower than pc.

The slope of curve between the creep strain and the logarithmic time becomes gentle with the elapsed time.

} Applied pressure is lower than pc

Applied pressure is around pcApplied pressure is higher than pc

Estimated compression curve of Ma7 clay

The relationship between compression strain and effective stress at the in-situ was obtained through calculation based on the field measurements of both pore pressure and compression of Ma7 clay layer.

A significant compression strain would occur at the in-situ, although the yielding does not occur in the conventional consolidation tests at the currently applied pressure, P0+p,.

P0 P0＋Δp Δp=400kN/m2

OCR=1.0～1.7

Compression strain ε（％）

Effective stress ｐ’（kN/m2）

400 600 1000 2000 3000

○ 実測値標準圧密試験定ひずみ試験

Applied pressure in oedometer

Data points : The calculated results based on field measurements

Solid lines : Oedometer test

CRS test

Currently applied pressureInitial overburden pressure

Compression curve at the in-situ

Solid lines denote the results of conventional consolidation tests

Difference between in conventional consolidation tests and at the in-situ

Drainage path length is 10mm in the conventional consolidation tests.– Strain rate is very rapid

Drainage path length is more than 10m at the in situ.– Strain rate is very slow

Difference of strain rate is one of very important factors.– Time-dependent mechanical characteristics will affect

consolidation behavior.

11

Objects of the research A series of numerical simulation is carried out in

order to investigate the effect of drainage path length on the long-term consolidation behavior of quasi-overconsolidated clays in the range of stress lower than pc.

The effect of drainage path length on compression behavior of the Pleistocene clays is discussed from the viewpoint of time-dependency.

Outlines of proposed model for quasi-overconsolidated clays Subloading surface theory is applied to express

smooth transition of time-independent compression behavior in the range of stress from around p0 to over pc.

'1 '

p dp dRdve p R

0

11

p pev dve

Outlines of proposed model for quasi-overconsolidated clays Flow surface theory is applied to express time-

dependent compression behavior, such as secondary consolidation.

0

lnv

v vvv

max

0

1 exp lnvvv

1max

0

1 1dt y dyv y B

max

1 exp vy B v B

Schematic diagram of proposed model

Compression curves are do not follow the conventional e-log p’ relationship.– Non-linear relationship between void ratio and logarithmic consolidation pressure is

applied. Isochronal compression curves are parallel to each other, however, the interval

between each curve decreases with decrease of vertical strain rate, so that the slope of curve between the creep strain and the logarithmic time becomes gentle with the elapsed time

310

Com

pres

sive

stra

in

Consolidation pressure (logarithmic scale) Elapsed time (logarithmic scale)

Stra

in d

ue to

seco

ndar

yco

nsol

idat

ion

*) Solid lines denotethe isochronal compression curves

410

510

610

710

Strainrate

Secondaryconsolidation

12

Numerical simulations One-dimensional consolidation elasto-

viscoplastic consolidation finite element method is applied.

Mechanical parameters used in the analysis are determined from a series of long-term consolidation tests of Ma10 clay, middle Pleistocene clay of Osaka Bay.

The drainage path length is chosen as a variable parameter in the numerical simulation.

Physical properties of Ma10depth -120m~-135m

wL (%) 111 wp (%) 52

Ip 59 s (g/cm3) 2.606

w0 (%) 72 e0 1.91

p0 (kN/m2) 1020 pc [CRS](kN/m2) 1530

deep

•The clay was taken from deep layer.•Over consolidation ratio is almost 1.5.

Applied pressures in long-term consolidation tests of Ma10 clay

In experimental cases from Case-10-1 to Case-10-3, a series of long-term consolidation tests were carried out in the range of stress lower than the consolidation yield stress.In Case-10-4, the test was carried out in the stress almost equal to consolidation yield stress. In Case-10-5 and Case-10-6, the tests were carried out in the range of stress higher than the consolidation yield stress.

Analytical parametersλ 0.801κ 0.106

max 0.012(1/min) 8.0×10-10

ν 0.024R0 0.5

k0(cm/min) 3.5×10-6

Ck 0.2α 1/4β -0.5

0v

13

Applicability of proposed model

Ma10 clay

Elapsed time (min)

Ver

tical

stra

in (%

)Solid curves : Anaytical resultsData points : Experimental results

15

12

9

6

3

0

-3

1x10

-1

1x10

0

1x10

1

1x10

2

1x10

3

1x10

4

1x10

5

1x10

6

Applied pressure:1170kPa (lower than pc):1260kPa (lower than pc):1310kPa (lower than pc):1460kPa (equal to pc):1610kPa (Higher than pc):1750kPa (Higher than pc)

BFH

EGA

Strain rate (1/sec)

Ver

tical

stra

in (%

)

Ma10 claySolid curves: Analytical resultsData points: Experimental results

15

12

9

6

3

0

-3

1x10

-3

1x10

-4

1x10

-5

1x10

-6

1x10

-7

1x10

-8

1x10

-9

1x10

-10

Applied pressure:1170kPa (lower than pc):1260kPa (lower than pc):1310kPa (lower than pc):1460kPa (equal to pc):1610kPa (Higher than pc):1750kPa (Higher than pc)

BFH

EGA

Vertical strains vs. Elapsed time Vertical strains vs. Strain rate

The numerical simulation can reproduce very well a series of long-term consolidation test of Ma10 as shown in above Figures.

Analytical cases

Cases Applied pressure （kPa）

Drainage path length (cm)

Case13-1 1310 1(Oedometer tests)

Case13-2 1310 5

Case13-3 1310 10

Case13-4 1310 50

Case13-5 1310 100

Case13-6 1310 500

Case13-7 1310 1000

Case13-8 1310 2000

Case13-9 1310 4000

Drainage path length is varied from 0.01m to 40.0m in the parametric study. Drainage path length of 0.01m corresponds to that of specimen in conventional consolidation tests such as oedometer, meanwhile the drainage path length of over 10.0m is almost equivalent to field size of Pleistocene clay layers in Osaka Bay.The yielding did not occur in the test at the stress of the applied pressure of 1310kPa.

Therefore, it can be generally considered that a significant settlement will not occur.

Analytical results

7

6

5

4

3

2

1

0

-1

1x10

-4

1x10

-3

1x10

-2

1x10

-1

1x10

0

1x10

1

1x10

2

1x10

3

1x10

4

1x10

5

1x10

6

1x10

7

1x10

8

1x10

9

1x10

10

H=0.01m

H=0.1m

H=10.0m

H=1.0m

H=5.0m

H=20.0mH=0.05m

H=0.5m

H=40.0m

Elasped time (min)

Ver

tical

stra

in (%

)

0

50

100

150

200

250

300

1x10

-4

1x10

-3

1x10

-2

1x10

-1

1x10

0

1x10

1

1x10

2

1x10

3

1x10

4

1x10

5

1x10

6

1x10

7

1x10

8

1x10

9

1x10

10

Elasped time (min)

Ave

rage

exc

ess p

ore

pres

sure

(kPa

)

H = 0.01m

H = 10.0m

H = 5.0m

H = 1.0m

H = 0.5mH = 0.1m

H = 0.05mH = 0.01m

H = 40.0m

In the case of drainage path length shorter than 0.5m, the vertical strain becomes temporarily stable at about 1.5%, and the required time to become about 1.5% is longer with increase of drainage path length.

The significant vertical strain occurs again after the elapsed time of about 104 minutes, regardless of drainage path length.

The increase of vertical strain stops once, as the excess pore pressure dissipates completely.

The vertical strain of about 1.5% should be caused by the primary consolidation. The significant increase of vertical strain after the elapsed time of about 104 minutes will occur due to the time-dependent mechanical characteristics such as secondary consolidation.

Vertical strain vs. Elapsed time

Average excess pore pressure vs. Elapsed time

Analytical results

7

6

5

4

3

2

1

0

-1

1x10

-4

1x10

-3

1x10

-2

1x10

-1

1x10

0

1x10

1

1x10

2

1x10

3

1x10

4

1x10

5

1x10

6

1x10

7

1x10

8

1x10

9

1x10

10

H=0.01m

H=0.1m

H=10.0m

H=1.0m

H=5.0m

H=20.0mH=0.05m

H=0.5m

H=40.0m

Elasped time (min)

Ver

tical

stra

in (%

)0

50

100

150

200

250

300

1x10

-4

1x10

-3

1x10

-2

1x10

-1

1x10

0

1x10

1

1x10

2

1x10

3

1x10

4

1x10

5

1x10

6

1x10

7

1x10

8

1x10

9

1x10

10

Elasped time (min)

Ave

rage

exc

ess p

ore

pres

sure

(kPa

)

H = 0.01m

H = 10.0m

H = 5.0m

H = 1.0m

H = 0.5mH = 0.1m

H = 0.05mH = 0.01m

H = 40.0m

In the case of drainage path length longer than 5.0m, the vertical strain monotonically increases.

Also, the average excess pore pressure still remains at the elapsed time of about 104 minutes. That is, the primary consolidation is not yet over.

The time-dependent mechanical characteristics can not be ignored before the end of primary consolidation, because they become remarkable after the elapsed time of about 104 minutes.

Therefore, the primary consolidation behavior in these cases is affected significantly by time-dependent mechanical characteristics.

Vertical strain vs. Elapsed time

Average excess pore pressure vs. Elapsed time

14

8.0

6.0

4.0

2.0

0.0

1000 1100 1200 1300 1400Vertical effective stress (kPa)

Ver

ticva

l stra

in (%

)

H = 40.0mH = 20.0m

H = 10.0m

H = 5.0m

H = 1.0m

H = 0.5m,0.1m,0.05m,0.01m

Effect of drainage path length on compression curve

Secondary consolidation

The compression curves between vertical effective stresses of 1020kPa and 1310kPa are almost straight lines in the cases of drainage path length less than 0.5m, because the secondary consolidation does not occur before the end of primary consolidation.The direction of compression curves

sharply turn downward at the vertical effective stress of 1310kPa. The vertical strains significantly increase due to the secondary consolidation without any change of vertical effective stress.

End of primary consolidation

8.0

6.0

4.0

2.0

0.0


Ver

ticva

l stra

in (%

)

H = 40.0mH = 20.0m

H = 10.0m

H = 5.0m

H = 1.0m

H = 0.5m,0.1m,0.05m,0.01m


In conventional consolidation tests

Secondary consolidation

Compression curves in the case where drainage path length less than 0.5m are coincident with each other.As drainage path length of 0.01m

corresponds to that of specimen in conventional consolidation tests, the compression curve before the occurrence of secondary consolidation coincides with that obtained through conventional consolidation tests.

8.0

6.0

4.0

2.0

0.0


Ver

ticva

l stra

in (%

)

H = 40.0mH = 20.0m

H = 10.0m

H = 5.0m

H = 1.0m

H = 0.5m,0.1m,0.05m,0.01m



Compression curves in the cases of drainage path length greater than 5.0m, are affected by time-dependent mechanical characteristics.The longer the drainage path

length, the earlier the compression curves is separated from that in the cases of drainage path length less than 0.5m.Especially, the compression curve

in the case of drainage path length of over 20.0m is separated at around the beginning.After the compression curve being

separated, the slope of compression curve becomes steeper.

Comparison between filed measurements and Numerical simulation

The numerical simulation can qualitatively reproduce the occurrence of the significant residual settlement.

The difference of compression behavior between in conventional consolidation tests and the in-situ will be caused by strain rate in the consolidation process.

8.0

6.0

4.0

2.0

0.0


Ver

ticva

l stra

in (%

)

H = 40.0mH = 20.0m

H = 10.0m

H = 5.0m

H = 1.0m

H = 0.5m,0.1m,0.05m,0.01m


P0 P0＋ΔpΔp=400kN/m2

OCR=1.0～1.7

Compression strain ε（％）

Effective stress ｐ’（kN/m2）

400 600 1000 2000 3000

○ 実測値標準圧密試験

定ひずみ試験

Applied pressure in oedometer

Data points : The calculated results based on field measurements

Solid lines : Oedometer test

CRS test

Currently applied pressure

Initial overburden pressure

Conventional consolidation tests

Compression curve at the in-situ

At the in-situ

15




Osaka Bay– Spatial estimation of soil properties with ANN

Estimationby NN

Information from GIbase

to estimate properties of Holocene Clays at arbitrary position in Kansai

International Airport from limited number of soil investigations with ANN

PURPOSEThe purpose of this study is

Interpolation

58

ＮＮ model

THINK

weight

θx1：xn

outw1

：wn

Neurons in the human brain are reproduced mathematically

ARTIFICIAL NEURAL NETWORK （ANN）

a large number of neurons

in human brain

OUTPUT

INPUT

modeliza

tion

OUTPUTINPUT

THINK

59

The clay properties at an arbitrary position were estimated.

back propagation neural network

example

Natural Water Content

weight

Depth

East

North

datasets for construction of

NN model

soilproperties

OUTPUT

coordinates

INPUTInput layer Output layerHidden layer

CONSTRUCTION OF ANN MODEL

etc… estimatedvalues

targetvalues

coordinates soilproperties

60

16

Subject area 15

Number of boring

184

Number of data

947

Input data ・Longitude・Latitude・Depth・Consolidation・pressure

Output data Natural water content,Liquid limite‐log p’ curve

Holocene clays : Kansai International Airport

Locations of soil investigations

ANALYSIS RESULTThree dimensional distribution

62Natural Water Content (WN)

Three dimensional distribution

63Liquid limit (Wl) e-logp relationship

◎One‐dimensioinal consolidation curves

➣The agreement ➣between the ➣target value and ➣estimated value ➣is excellent

18

Consolidation pressure(kPa)

Void ra

tio

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

1 100 10000

estimatedSample A

estimatedSample B

estimatedSample C

Sample A

Sample B

Sample C

17

Summary

Construction of Kansai International Airport started in 1987. We have faced various geotechnical problems. Some of these problems had already worked out. However, the unsolved problems still remains now. Also, the new problems will arise. We need to efforts to work out these problem more and more. The results of our research works about Kansai International Airport will contribute for development of the geotechnical engineering.

OSAKA UNIVERSITY

Thank You for your attention

OSAKA UNIVERSITY

Structure of Seawall

18

Settlement of the Kansai Airport

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

1987/9 1988/9 1989/9 1990/9 1991/9 1992/9 1993/9

Sett

lem

ent

(m)

Measured(Total)

Measured(Alluviallayer)Measured(Pleistocene layer)Analytical(Total)

Analytical(Alluvial)

01020304050

1987/9 1988/9 1989/9 1990/9 1991/9 1992/9 1993/9 1994/9

Time

Ove

rburd

en s

tress

(tf/

m2)

１３ＥＣＳＭＧＥ，ＰＲＡＨＡ，２００３ OSAKA UNIVERSITY

Variation of measured settlement at ground level of the Kansai Airport island (phase I) with time

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

1987 1988 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001

Year

Obs

erv

ed

Sett

lem

ent

（ｍ

）

Opened Airport

Final Reclamation

A

B

C

1st Phase Island


Spread foundation with improvement of SCP around PTB and railway station


Geological profile at A-A section of Kansai Airport site


19

My research topics Application of numerical simulation

– Load & displacement behavior of bored pile– Deformation behavior of soil structures on soft clay

ground– Improvement of clay ground with Sand compaction pile

method Mechanical behavior of undisturbed clay and its

numerical modeling Application of artificial intelligence to geotenical

engineering. Etc.

structures on and within man-made deposits...

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