Proceedings of the First International Conference on Press-in Engineering 2018, Kochi

Experimental Study on Influence of a Pile Penetration on Deformation of a
Buried Pipe in Sand
Kensuke MORITA
Civil engineer, Sato Kogyo Co. Ltd., Tokyo, Japan

Tatsunori MATSUMOTO
Professor, Graduate School of Kanazawa University, Kanazawa, Japan
Email: matsumoto@se.kanazawa-u.ac.jp

Anh Tuan VU
Lecturer, Department of Civil Engineering, Le Quy Don Technical University, Hanoi, Vietnam

ABSTRACTIn this paper, influence of installation of new piles on an existing buried pipe was investigated through small-scale model
tests. Close-ended aluminum pipes of 595 mm in length and 32.0 mm in outer diameter were used for the model piles indry sand model ground. A close-ended PVC pipe of 700 mm in length and 18.0 mm in outer diameter was used as aburied pipe model. The PVC pipe was instrumented with axial strain gauges to obtain bending moments in vertical andhorizontal directions. The PVC pipe was set in the model ground horizontally at a depth 230 mm. The model piles werepressed-in into the ground from the ground surface at locations near the buried pipe. The distributions of the buried pipe
displacements in the vertical and horizontal directions were estimated using the measured bending moments. The
experiments were carried out in dense (relative density Dr = 80%) and loose (Dr = 50%) sand grounds. The paper presents
the experimental results, and discusses the influential factors, such as distance between the piles and the buried pipe, thepile tip level and soil density, on the deformation of the buried pipe.

Key words: Buried pipe, Pile installation, Experiment, Deformation, Sand

In this research, fundamental small-scale model tests

1. Introduction
Owing to recent developments of press-in or jack-in

were carried out to investigate how installation of new

machines for piles and/or sheet piles, precise positioning

piles affects the behaviours of an existing pipe buried in

of installed piles became possible and the construction

dry sand model ground.

machine is able to access the vicinity of existingsuperstructures or underground structures such as piles,

2. Experiment description

underground walls and buried pipes. In Japanese pile
design codes, it is prescribed that interaction (pile group

2.1. Model pile
Close-ended aluminum pipes having a length, L , ofeffects) between two piles can be negligible if centre-to

595 mm, an outer diameter, Do, of 32.0 mm and an innercentre pile spacing, s, is greater than 2.5. The authors,

diameter, Di, of 29.3 mm were used for the model piles.

however, have a doubt on this specification. Also, in case

The specifications of the model pile are listed in Table 1.

of installing a new pile in the vicinity of a buried pipe,

Each model pile (P1, P2 and P3) was instrumented with

influence of the newly installed pile on the buried pipe

strain gauges at 5 different levels, and the pile shaft was

may not be negligible.

coated with sand particles to increase the shaft resistance,
as shown in Fig. 1.

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Proceedings of the First International Conference on Press-in Engineering 2018, Kochi

Table 1.

Specifications of model pile

Table 2.

Specifications of model buried pipe

Pile length, Lp (mm)595

Length, Lpipe (mm)Outer diameter, Do (mm)32

Outer diameter, Do pipe (mm)

Inner diameter, Di (mm)29.3

Inner diameter, Di pipe(mm)Wall thickness, tw (mm)

18.03
12.56
2

Cross-sectional area, Apipe (mm )

1.35

701

131.4

4

Density, p (g/cm3)

2.70

Young's modulus, Ep (MPa)65,4001

50Poisson's ratio, p

0.33

2

150

3

250

4

350

5

450

6

550

7

650

Moment of inertia, Ipipe (mm )3965.8

Position of strain gauges（Distance from pipe end, in mm）

75

25

SG6

Young’s modulus, Epipe (N/mm )2705.3

Poisson's ratio, pipe

0.407

2

SG2

100

600 mm

175

SG1

SG3

2

100

Shear modulus, Gpipe (N/mm )

SG4

100

100

100

100

100

100

51

100

50

961.4

2

1

3

75

SG5

strain gauge

4

701mm

strain gauge

5

6

7

Outer diam. = 18.03 mm
Inner diam. = 12.56 mm

Outer diam. = 32.0 mm
Inner diam. = 29.3 mm

Fig. 1Model pile instrumented with strain gauges
Fig. 22.2. Model buried pipe

Model buried pipe instrumented with strain gauges

A PVC (PolyVinyl Chloride) pipe having Lpipe = 701
Table 3.

mm, Do pipe = 18.0 mm, Di pipe = 12.6 mm was used as a

Physical properties of silica sand #6

buried pipe. Both ends of the PVC pipe were closed

Mean particle size, D50 (mm)0.21

(capped) to prevent intrusion of sand particles inside theSoil particle density, s (ton/m3)

2.67

pipe. The specifications of the PVC pipe are listed inMax. dry density, dmax (ton/m3)

1.60

Min. dry density, dmin (ton/m3)

1.27

section, 4 strain gauges were glued on the pipe shaft 90

Max. void ratio, emax

1.10

degrees apart, to obtain bending moments in vertical andMin. void ratio, emin

0.66

Table 2. The pipe was instrumented with axial strain
gauges at 7 sections (see Fig. 2). At each measurement

horizontal directions.

The sand was poured in the soil box by about 50 mm
thick and tamped to have prescribed relative density, Dr,

2.3. Model groundDry silica sand #6 was used for model ground in theexperiments. The physical properties of the sand are listed
in Table 3.

horizontally in the ground as shown in Fig. 3 in the processof ground preparation. After the setting of the pipe, sandA model ground was prepared in a rigid box having
dimensions of 800 mm in length, 500 mm in width and530 mm in depth.

of 80% (d = 1.53 t/m3, called dense ground) or 50 % (d= 1.42 t/m3, loose ground). The model pipe was set

pouring and tapping were repeated until the total groundheight reached 530 mm (10 layers of 50 mm in thickness
and 1 layer of 30 mm in thickness).

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Proceedings of the First International Conference on Press-in Engineering 2018, Kochi

Silica sandDeviatoric stress, q (kPa)

500

230 mm
500mm

800 mmp0= 100 kPa
p0= 100 kPa
cyclic400300

p0= 50 kPa

200
p0= 27 kPa

100
p0= 17 kPa

0
0

2

4

6

p0= 7 kPa8

10 12 14 16 18 20

Axial strain, a (%)(a) Axial strain a vs deviatoric stress q
Silica sandModel ground and the buried pipe

-12Cone penetration tests (CPTs) were conducted in themodel ground after the completion of experiments in eachmodel ground. The diameter of the cone used was 20.5mm which was smaller than that of the outer diameter ofthe model pile. Fig. 4 shows the CPT results in the dense
and loose model grounds. In both grounds, the tip
resistance, qt, increases almost linearly with depth,

Volumetric strain, vol (%)

Fig. 3-4-2

p0= 100 kPa

0
2
0

2

4

6

8

10 12 14 16 18 20

Axial strain, a (%)

5

10

Fig. 51550

Deviatoric stress, q (kPa)0Dense ground
Loose ground

200

Dense
(Dr = 80%)

300
400

Results of triaxial CD tests for the dense sandCD test (Silica #6), Dr = 52 %4030

p0 = 10.5 kPa
20
10
0
0

2

4

6

8

10 12 14 16 18 20

Axial strain, a (%)500(a) Axial strain a vs deviatoric stress q

Loose(Dr = 50%)

CD test (Silica #6), Dr = 52 %

-12

600
CPT results in the dense and loose model grounds

2.4. Triaxial CD tests of the sandIn order to grasp the mechanical behaviours of thesand, a series of triaxial CD compression tests were carriedout (Vu, 2017). For the dense sand (Dr = 80%), five CD
tests were carried out with different confining pressures,

Volumetric strain, vol (%)

Pile head disp., wh (mm)p0= 100 kPa
cyclicp0= 50 kPa(b) Axial strain a vs volumetric strain volCone tip resistance, qt (MPa)Fig. 4p0= 27 kPa-6loose ground.

100

p0= 17 kPa-8although qt in the dense ground is about 5 times that in the0p0= 7 kPa

-10

-10
-8
-6
-4
-2
0
2
0

50%), a CD test with p0 = 10.5 kPa was carried out. The
results of the CD tests are shown Fig. 5 and Fig. 6.

4

6

8

10 12 14 16 18 20(b) Axial strain a vs volumetric strain volFig. 6- 411 -

2

Axial strain, a (%)

p0, of 7, 17, 27, 50 and 100 kPa. For the loose sand (Dr =Results of triaxial CD test for the loose sand

Proceedings of the First International Conference on Press-in Engineering 2018, Kochi

For the dense sand, the internal friction angle, p', atpeak peak strength is 42.8 degrees and the friction angle

stresses and higher density of the surrounding soils. P2

at residual state, r', is 35 degrees. It is seen from Fig. 5(a)reasonable that P2 has higher Ph and that P3 is subjectedthat the initial stiffness, q/a, increases almost linearly

to more influence from the previously installed piles P1

with increase in the square root of p0. It is seen from Fig.

and P2.

was pushed into the influenced soils. Hence, it is5(b) that a small amount of negative dilatancy occurs at a

The pile head load, Ph, of P1 in the loose ground isvery early stage of shearing followed by a large amount ofmuch lower than that in the dense ground, as expected

positive dilatancy. Positive dilatancy behaviour weakens

from the CPT results in both grounds (Fig. 4).

after the axial strain, a, exceeds about 8%.
The results of the CD test of the loose sand show

112mm 80mm

similar trend to those of the dense sand, although p' andr' of the loose sand is 38 degrees. It is seen fromcomparison of the dilatancy curve of the dense sand with

64mm
=2D

500
mm

P2

P1
53

64

p0 = 7 kPa (Fig. 5(b)) and that of the loose sand with p0 =

250
mm

P3
Pipe

701 mm10.5 kPa (Fig. 6(b)) that degree of positive dilatancy is
reduced in the loose sand.
800 mm

2.5. Test procedure

Close-ended pipe pile(a) Top view

The same test procedure was used basically in theexperiments in the dense and the loose grounds. The PVC

P2

P1

P3

pipe was buried in the model ground horizontally at a
depth of 230 mm, as shown in Fig. 3 (the depth is definedas the depth of the axis of the PVC pipe). Thereafter, the
230
mmmodel pile P1 was pressed into the ground first quasiBuried pipe

statically at a penetration speed of 0.2 mm/s until the pile

530mm

tip level reached about 400 mm depth. Then, the pile P2
was pressed into the ground similarly, and finally the pile
P3 was installed. The locations in plan of P1, P2 and P3 inthe case of the dense sand are shown in Fig. 7(a). For an
example, the horizontal distance between the axis of P1

800 mmand the shaft of the PVC buried pipe was 64 mm. Note thatin the case of the loose sand, the horizontal distanceFig. 7

between P1 and the PVC pipe was 85 mm although 64 mm
was intended.

(b) Side view
Locations of the buried pipe and the piles

Pile head load, Ph (N)Pile head disp., wh (mm)03．Experimental results
3.1. Penetration resistance of piles in the dense andloose grounds
Fig. 8 shows the pile head load, Ph, (penetration
resistance) with the pile head displacement (almost equal
to the pile tip depth), wh, measured in the cases of thedense and the loose grounds. In the case of the dense sand,Ph is larger in the piles pushed-in later, especially for
depths greater than 250 mm. Penetration of P1 would havedisplaced the soils surrounding the pile, resulting in higher

1000

2000

3000

4000

0
100

Pile 1 (Dr = 80%)
Pile 2 (Dr = 80%)
Pile 3 (Dr = 80%)200

Pipe depth = 230mm

300
400

Pile 1(Dr = 50%)

P1

P3
P2

500

Fig. 8 Penetration resistance of pile in the dense and loose
grounds- 412 -

Proceedings of the First International Conference on Press-in Engineering 2018, Kochi

It is interesting notice that the ratio of CPT valuesof P1, P2 and P3 in the dense ground at various wh.

between the dense and loose model was around 5 as shown

Bending moment, Mv, which causes curvature of thein Fig. 4, while the ratios of the press-in force between

buried pipe convex downward is taken as positive. Fig. 10

them are less than 3 as indicated in Fig. 8. This is becauseshows the bending moments of the buried pipe in the

the CPT values are related only with the resistance on thehorizontal direction, Mh. Bending moment, Mh, which

tip while the press-in force is related with both thecauses curvature of the buried pipe convex outward fromresistance on the tip and on the shaft.

the pile position is taken as positive.
Let us focus on Fig. 9(a) first. It is clearly seen that

3.2. Behaviours of the buried pipe in the dense groundFig. 9 shows the bending moments of the buried pipe

large bending moments are generated at the position of P1(at x = 350 mm).

in the vertical direction, Mv, measured during installations
1

0

3000
2500
2000
1500
1000
500
0
-500
-1000
-1500
-2000

100 200 300

duringpenetrationof P1

Distance from pipe end, x (mm)Bending moment, Mh (N mm)

Bending moment, Mv (N mm)0

Bending moment, Mv (N mm)

Distance from pipe end, x (mm)
400 500 600 7003

0100 200 300 400 500 600 700
12000
5
10000
during(a)
8000
penetration
6000
of P1
3
4000
2000
2
0
1
-2000
-4000
-6000

(a)

2
4
1
5

100 200 300

Distance from pipe end, x (mm)Bending moment, Mh (N mm)

Distance from pipe end, x (mm)
400 500 600 700

4000
3

3000
2000

2

1000

12000
10000
8000
6000
4000
2000
0
-2000
-4000
-6000

during penetration
of P2

4

0
-1000

1

-2000

5

-3000

(b)

8

0

-4000

5

100 200 300

4000

400 500 600 700

2000

during penetration
of P3

(b)

2
1

0

100 200 300

400 500 600 700

12000

3
4
2

0
-2000
-4000

(c)

-6000

during penetrationof P2

Distance from pipe end, x (mm)Bending moment, Mh (N mm)

Bending moment, Mv (N mm)

0

400 500 600 700

3Distance from pipe end, x (mm)6000

100 200 300

5

8000

8
3

(c)

4000
2

0
1

-4000

during penetration
of P3

0
0
0
0
0
0

3
2
1

Bending moment, Mh (N mm)

-8000
-8000
wh (mm)wh (mm)100 (1)150 (2)200 (3)(4)100 (1)150 (2)200 (3)230 (4)
0100
200
300
400
500
600
700
0230
100
200
300
400
500
600
700
0
12000 390 (8)
250
(5)
270
(6)
300
(7)
250
(5)
270
(6)
300
(7)
390 (8)5
50uring10000
duringFig. 9 Bending moments of the buried pipe in the vertical Fig.10 Bending moments of the buried pipe in the horizontal
0enetration
8000
penetration
direction, Mv (in dense ground)direction, Mh (in dense ground)
of P1
0 P1
6000
4000
2000
0
-2000
-4000
-6000

3
2
1

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Proceedings of the First International Conference on Press-in Engineering 2018, Kochi

Change of distributions of Mv is complicated. Mv at x

Next, let us look at Fig. 10(a) where bending= 350 mm increases with increasing wh until wh increases

moments in the horizontal direction, Mh, generated

to 200 mm. However, Mv decreases for further pileduring the installation of P1 are shown. Large bending

penetration, e.g. Mv at wh = 230 mm (4) is smaller than thatmoments are generated at the position of P1 (at x = 350

at wh = 150 mm (2) and wh = 200 mm (3). The peak Mv ismm). Mh at x = 350 mm increases with increasing wh untilcaused at wh = 200 mm, just before the pile tip level reach

wh increases to 250 mm which a little bit deeper than thethe depth of the buried PVC pipe (230 mm depth from thedepth of the PVC pipe (230 mm depth from the groundground surface).

surface). Thereafter, Mh starts to decrease a little bit for

200 300-1

400 5003
2

0

600 700

1
4

1

5

2

6

duringpenetration
of P1

3
4

7

(a)

8

Pipe vertical disp., zpipe (mm)Pipe vertical disp., zpipe (mm)Distance from pipe end, x (mm)0100

200 300

0

400 500

600 700

during penetration
of P2

2

3

2

4
5
6

6

7

8

(b)
8

10

Distance from pipe end, x (mm)0100

200 300

400 500

600 700-20during penetration of P3

2
3

4
6

4

8
10
12

7

(c)

8

14
wh (mm)Pipe horizontal disp., ypipe (mm)100

Pipe horizontal disp., ypipe (mm)Distance from pipe end, x (mm)0Pipe horizontal disp., ypipe (mm)Pipe vertical disp., zpipe (mm)further pile penetration.
Distance from pipe end, x (mm)
0
10
9
8
7
6
5
4
3
2
1
0
-1

100

200 300

400 500

duringpenetrationof P1

600 700

(a)

8
5

1

4
3

2
1

Distance from pipe end, x (mm)0100

200 300

14

400 500

600 700

8

12

5

10

3

8

2

(b)

4

1

6
4
2
0

during penetration of P2-2

Distance from pipe end, x (mm)
0
20
18
16
14
12
10
8
6
4
2
0
-2

100

200 300

duringpenetrationof P3

400 5008

1

600 700

(c)

3 4
2

wh (mm)Bending moment, Mh (N mm)

100 (1)150 (2)200 (3)(4)100 (1)150 (2)200 (3)230 (4)
0100
200
300
400
500
600
700
0230
100
200
300
400
500
600
700
0
12000 390 (8)
250
(5)
270
(6)
300
(7)
250
(5)
270
(6)
300
(7)
390 (8)5
50uring10000
during0enetration
8000
penetration
Fig. 11 Displacements of the buried pipe in the verticaldirection, Fig. 12 Displacements of the buried pipe in the horizontal
of P1
0 P1
6000
z
direction, ypipe (in dense ground)pipe (in dense ground)
3
3
0
4000
0
2000
2
2
0
0
1
1
0
-2000
- 414 0
-4000
0
-6000

Proceedings of the First International Conference on Press-in Engineering 2018, Kochi

When P2 or P3 was installed, similar behaviours ofbending moments, Mv and Mh, of the PVC pipe were

penetration, influence of the pile penetration on thevertical displacements is small.

observed. Large values of Mv and Mh were generated at

It is seen from Figs. 11(b) and 11(c) that upward-

the positions of P2 (x = 240 mm) or P3 (x = 430 mm).

displacements of the buried pipe are caused until wh

Similar to the changes of the vertical bending moments

reaches 200 mm and downward-displacements are

Mv during the installation of P1, Mv increases withcaused for further pile penetration. It is interesting that atincreasing wh until wh of P2 or P3 increases to 200 mm.

the end of penetration of P3, the distribution of the

However, Mv decreases for further pile penetration (seevertical displacements of the buried pipe is almost

Figs. 9(b) and 9(c)).

symmetrical.

The horizontal bending moments, Mh, increase with

Next,

let

us

see

Fig.

12(a).

Horizontal

increasing wh until wh increases to 250 mm. Thereafter,

displacements of the buried pipe, ypipe, increase with

Mh starts to decrease a little bit for further pile penetration

increasing pile tip depth, wh. Most part of the horizontal(see Figs. 10(b) and 10(c)).

displacements occurs until wh reaches 250 mm. The

The vertical displacement, zpipe, and horizontal

horizontal displacements of the buried pipe are scarcely

displacement, ypipe, of the buried pipe were estimatedaffected by further pile penetration greater than wh = 250

from the measured distributions of Mv and Mh,

mm. It is seen from Fig. 12(c) that the distribution of therespectively.
The vertical displacement of the pipe, zpipe, wascalculated using the elastic beam theory given by Eqs. (1)and (2).

horizontal displacements of the buried pipe is almost𝑑 2 𝑧pipe (𝑥)
𝑑𝑥 2

(1)

𝑀
𝑧pipe (𝑥) = −∬ v d𝑥d𝑥 + 𝐶1 𝑥 + 𝐶2
𝐸𝐼

(2)

𝑀v (𝑥) = −𝐸𝐼symmetrical at the end of penetration of P3. The
magnitudes of the horizontal displacements are about 1.5
times those of the vertical displacements.
3.3. Behaviours of the buried pipe in the loose ground
Measured behaviours of the buried pipe duringpenetration of P1 in the loose sand ground are shown in

Two assumptions were made to obtain theFigs. 13 to 16.

distribution of zpipe: 1) bending moments at both ends ofAs mentioned earlier, the horizontal distancethe pipe are zero, and 2) displacements at the both ends

between the buried pipe and P1 was 85 mm, which wasof the pipe are zero. Similar procedure was used togreater than 64 mm in the case of the dense ground.

estimate ypipe.

Trends of the behaviours of the buried pipe in theFig. 11 shows the displacements of the buried pipein the vertical direction, zpipe, during installations of P1,

loose ground are similar to those in the dense ground(Figs. 9(a), 10(a), 11(a) and 12(b)).

P2 and P3 in the dense ground at various wh. Downward-

Distance from pipe end, x (mm)Bending moment, Mv (N mm)

displacement is taken as positive and upward-0
100 200 300 400 500 600 700
1200
displacements of the buried pipe in the horizontal
1000
2
direction, ypipe. Horizontal displacement outward from
3
800
600
the pile position is taken as positive.
400
Let us look at Fig. 11(a). Large amplitudes of the1
200
vertical displacements are found at the position of P1 (x0= 350 mm). Upward displacements of the buried pipe are-200
caused until the pile tip depth, wh, reaches 200 mm. When
-400
-600
the pile tip depth reaches 230 mm which is the depth ofwh (mm)the buried pipe, downward-displacements of the0100
buried100 (1)150 (2)200 (3)230 (4)
200
300
400
500
600
700
250 (5)270 (6)300 (7)390 (8)pipe are caused. Downward-displacements12000
continue to5
10000
duringFig.
13
Bending
momentsoftheburiedpipe
inthe verticalincrease until wh reaches 300 mm. For 8000
furtherpilepenetration
direction, Mv (in loose ground)
of P1
6000
Bending moment, Mh (N mm)

displacement is taken as negative. Fig. 12 shows the

4000
2000
0
-2000
-4000
-6000

3
2 - 415 1

Proceedings of the First International Conference on Press-in Engineering 2018, Kochi

Bending moment, Mh (N mm)

Distance from pipe end, x (mm)0

100 200 300

6000
5000
4000
3000
2000
1000
0
-1000
-2000
-3000

From comparison of Figs. 15 and 16 with Figs. 11(a)400 500 600 700

and 12(a), interesting findings are as follows. Magnitudes

4of displacements of the buried pipe in the vertical direction,
zpipe , in the loose ground are significantly smaller thanthose in the dense ground. For an example, the maximum
downward displacement of the buried pipe is 0.6 mm in

2
1

the loose ground, while that in the dense ground attains to
4 mm. In the case of the loose ground, magnitudes of the
upward displacements and the downward displacementsof the pipe are almost similar, while larger magnitudes ofwh (mm)100 (1)150 (2)200 (3)230 (4)
0100
200
300
400
500
600
700
0
250 (5)270 (6)300 (7)390 (8)50uringFig.14 Bending moments of the buried pipe in the horizontal
0enetration
direction, Mh (in loose ground)
0 P1
3
2
1

Distance from pipe end, x (mm)Pipe vertical disp., zpipe (mm)

0
0
0
0
0
0

0

100

200 300 400 500

duringpenetration
of P1

3 2

-0.2

1

buried pipe in the loose ground are comparable to those in
the dense ground.

existing buried pipe in dry sand. Although experimental
conditions considered in this paper are limited, it issuggested from the experimental results that relative

4

0.2

density of the sand, the distance between the installed piles

58

and the buried pipe, the number of the newly installed6

0.6

piles are influential factors.

7

wh (mm)100 (1)150 (2)200 (3)230 (4)
0100
200
300
400
500
600
700
0
250
(5)
270
(6)
300
(7)
390 (8)50uringFig. 15 Displacements of the buried pipe in the vertical direction,
0enetration
zpipe (in loose ground)
0 P1

Although the fixity conditions of the buried pipe also
may not be practical, the experimental method presented
in this paper will be useful to investigate the the influenceof newly installed piles on an existing buried pipe.

32
1

Pipe horizontal disp., ypipe (mm)

0
0
0
0
0
0

Magnitudes of the horizontal displacements of theinvestigate the influence of newly installed piles on an

0.0

0.4

ground.

4. Concluding remarks
Fundamental experiments were carried out to600 700-0.6-0.4

the downward displacements are generated in the dense

Acknowledgements

Distance from pipe end, x (mm)0100

200 300 400 500

6for his supports in the preparation and execution of the
8

5
4

4
3

duringpenetrationof P1

experiments in this research.
References
Vu, A. T. 2017. Experimental and Numerical Study on

3
2

The authors would like to thank Mr. Shinya Shimono

600 700

2

Behaviours

1

Group

and

Piled

Raft

Combination of Vertical and Cyclic Horizontal

0

3
2
1

Pile

Foundations Having Batter Piles Subjected to1

wh (mm)100 (1)150 (2)200 (3)230 (4)
0100
200
300
400
500
600
700
0
250
(5)
270
(6)
300
(7)
390 (8)50uringFig. 16 Displacements of the buried pipe in the horizontal, ypipe
0enetration(in loose ground)
0 P1

0
0
0
0
0
0

of

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Loading, Dr. Thesis of Kanazawa University, 164pp.