International Journal of GEOMATE, Feb., 2019 Vol.16, Issue 54, pp.81 - 85
Geotec., Const. Mat. & Env., DOI: https://doi.org/10.21660/2019.54.8132
ISSN: 2186-2982 (Print), 2186-2990 (Online), JapanSETTLEMENT OF SURROUNDING GROUNDS DUE TO
EXISTENCE OF PILE PULLING-OUT HOLES* Shuichi Kuwahara 1 and Shinya Inazumi 2
1

2

Marushin Co. Ltd., Japan;
Department of Civil Engineering, Shibaura Institute of Technology, Japan;* Corresponding Author, Received: 15 Sep. 2018, Revised: 02 Oct. 2018, Accepted: 06 Nov. 2018
ABSTRACT: The demolition of social infrastructures including the civil structures have been increasing
because of aging them constructed during in a period of high economic growth and decrease in their utilization
with a population decrease, in recent years. As a result, removal works of existing pile in the ground have been
increasing. Pulling-out method is adopted for removal of existing a pile foundation in the present circumstances.
However, after pulling-out a pipe foundation, decline of mechanical characteristic of surrounding ground isconcerned by forming pulling-out holes. There are no regulations yet for filler injected into a pulling hole, andthe influence of the strength of the filler on surrounding ground is not considered. This study considers theinfluence by which a pulling-out hole of a pipe foundation gives it to static characteristics of surrounding
ground by using 3D elastic-plastic finite element analysis. The special qualities required for fillers injected intoa pulling-out hole are also clarified in this study.
Keywords: Finite element method, Pile foundation, Pulling-out method, Pulling-out holeuse has increased. However, there are no
regulations yet on fillers injected into a pulling-out
hole, and the influence by which the strength of thefillers gives it to the surrounding grounds is not also
elucidated.
This study considers the influence by which apulling-out hole of a pile foundation gives it to static
characteristics of surrounding grounds by using
three-dimensional static finite element analysis.
The special qualities required for fillers injected
into a pulling-out hole are also clarified in thisstudy.
In this research, the analysis with static total
stress model is applied. As shown in Fig. 1, theprocedures of analysis are described in following(1) to (4).

1. INTRODUCTION
In Japan, many of the city located in the soft
ground, there are many structures using a pilefoundation. Therefore, to achieve a new land
utilization at the place where existed structures arepresent, it is necessary to remove existed pile
supported the structure as well as existed structures
for construction of a new structure. Further, existed
piles and concrete husk become industrial waste, beleft of these industrial waste in the ground is a very
difficult problem. In addition, it is seen troubles
many as "hidden defect" in the sale of landtransactions [1]. Accordingly, it can be said that theremoval of existed pile is essential.
The removal method of existed pile, there is apulling-out method and crushing removal method,
and the like. But the crushing removal method arehaving such as vibration, noise and environmental
problems. The pull-out method has been widelyused from this thing. However, there are also
problems in the pull-out method. The pulling-out
hole is formed when pulling out the existed pile. If
the pulling-out hole is left, the collapse of the empty
drilling part of the earth and sand, and there is apossibility that the subsidence of the ground surface
by the gap widening in the ground occurs.
Therefore, it is necessary to fill the pulling-out holeby injection of the fillers. About fillers,conventionally, in many cases to construction in
mountain sand and recycled sand from construction
it is easy and inexpensive. But, by cannot ensure areliable filling and stable strength, in recent years
the flow of processing soil and cement-bentonite

START

1. Select the study cross-section and input ground motion
2. Create the analysis model and mesh3. Select a configuration modelSet the material parameters
4. Static analysis of total stress method(initial stress analysis)

END

Fig. 1 Analysis procedure81International Journal of GEOMATE, Feb., 2019 Vol.16, Issue 54, pp.81 - 85yTable 1 Element parameters

20
m

26
m

Clay layer

Gravellayer

filler𝜸𝜸𝒕𝒕(kN/m3)

14

19

15

Constitutive
law

x

z

Material nameElastic-plastic model

Table 2 Ground parameters
Material nameClay layer

Gravel layer

𝑬𝑬(kN/m²)

7900

140000𝝂𝝂(-)(a) When the pulling-out holes are hollow

𝑺𝑺𝒖𝒖 (kN/m³)𝝓𝝓 (°)

y

0.45

0.35

37.8

152.9

0

42.3

Table 3 Filler parameters

20
m

26
m

z

x

Fillerqu(N/mm²)

1

0.1

2

0.5

3

1.0

𝑬𝑬
(kN/m²)
1.36
×10⁵
5.88
×10⁵
11.5
×10⁵

𝝂𝝂
(-)

𝑺𝑺𝒖𝒖
(kN/m³)
38.3

26.0

0.48

182.3

39.5

0.48

362.2

49.6

0.48

𝝓𝝓
(°)

three, pore diameter is 2 m, depth is 20 m, andembedment depth into the gravel layer is the 2 m.
For mesh division, improve the accuracy of analysis
by finer mesh spacing near the pulling-out hole.
Also, even when filled with pulling-out holes, it isfiner mesh in order to examine the behavior of thefilling portion of the pulling-out hole. As aboundary condition, the bottom is fixed fulcrum,
and the lateral boundary is fixed in the verticaldirection.
In the analysis, filler material is fluidization
treated soil [2], [3]. The analysis cross-sectionalview of the ground, analysis model and axial
direction are shown in Fig. 2. In the figure, theportion surrounded by red frame is hollow portionand blue frame is filler portion. And a yellow line
indicates a boundary between clay layer and gravel
layer.
Parameters in the clay layer and gravel layer
used for the analysis and soil parameters in thepulling-out hole are shown in Tables 1 and 2. In thisanalysis, using a fluidizing processing soil thatmany of the experimental value. In addition, it
analyzes in three fillers with different elastic
modulus of the fluidizing process soil in order toexamine the effect of filler strength has on the
ground. From having a small strength, the filler 1,(b) When the pulling-out holes are injected the filler
Fig. 2 Sectional view and Analysis model(1) Select analysis section.
(2) Create an analysis model based on the section
selected in (1) and divide the analysis region
into meshes.
(3) Select analysis constants. Set configuration
model and material parameters.
(4) Perform initial stress analysis. Here, the elastic
plastic model is applied to the ground part andthe filler part.
2. ANALYSIS OVERVIEW
In the analysis, the analysis cross-section has a
two-layer, upper layer part is clay layer as soft
strata, which N value is approximately 2. And underlayer part is gravel layer as strong formations
serving as a support layer, which N value isapproximately 50. The front and side width of theanalysis cross section is set to 50m, the thickness ofthe clay layer is 18m, the thickness of the gravel
layer is 8 m, and the total depth of the cross section
is 26 m. About pulling-out holes, the number is82

International Journal of GEOMATE, Feb., 2019 Vol.16, Issue 54, pp.81 - 85

X-direction
displacement
amount (m)-0.08

X-direction
displacement
amount (m)-0.001

0

0

0.08

0.001

(b) Filler 1 (qu=0.1N/mm2)(a) Pulling-out holes are hollow

X-direction
displacement
amount (m)-0.001

X-direction
displacement
amount (m)-0.001

0

0

0.001

0.001

(c) Filler 2 (qu=0.5N/mm2)(d) Filler 3 (qu=1.0N/mm2)

Fig. 3 X-direction displacement amount contour figure at ground surface

filler 2, filler 3. Parameters used in the analysis is todetermine the anamnestic literature reference (seeTable 3).
γ t represents unit volume weight of the soil. E
represents elastic coefficient. ν represents Poisson's
ratio. Su represents shear strength. ϕ representsinternal friction angle. q u represents compressive
strength.

types of fillers with different strength on thesurrounding ground by this study. Figure 4 is thecontour figure showing x-direction displacement
amount on the ground surface when the pulling-out
holes are hollow and when each filler with different
strength is fixed. Figure 5 is the contour figure
showing settlement amount on the ground surface
in the same case as above. Figure 6 is the graphcomparing settlement amount on the ground surface
in the same case as above. These are premises thatthe filler is injected uniformly [4].
From Fig. 3, the maximum x-direction
displacement amount is 0.080 m when the pullingout holes are hollow. In that case, it shows thatsurrounding ground is deforming to block thepulling-out holes. And the maximum x-direction
displacement amount is 0.001 m when the pulling-

3. RESULTS AND DISSCUSIONSIn this study, to compare the ground when
injecting three types of filler on the ground when thepulling-out holes are hollow, in the static analysis.
The results are shown in the following.
Figures 3, 4 and 5 show the results about theeffect of the pulling-out holes in the hollow and 3
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International Journal of GEOMATE, Feb., 2019 Vol.16, Issue 54, pp.81 - 85

Subsidence
amount (m)0.50

Subsidence
amount (m)
0.010

0.25

0.005

0

0
2

(b) Filler 1 (qu=0.1N/mm )(a) Pulling-out holes are hollow

Subsidence
amount (m)0.010

Subsidence
amount (m)
0.010

0.005

0.005

0

0

(c) Filler 2 (qu=0.5N/mm2)(d) Filler 3 (qu=1.0N/mm2)

Fig. 4 Settlement amount contour figure at ground surface

it can be said that ground improvement is necessary
because the settlement amount is large.
And the maximum settlement amount is 0.008
m when the pulling-out holes are fixed with filler 1(q u = 0.1 N/mm2). The area of influence ofsettlement in x-direction is -11 to 11 m. And the
maximum settlement amount is 0.004 m with filler
2 (q u = 0.5 N/mm2). The area of influence ofsettlement in x-direction is -9.5 to 9.5 m. And the
maximum settlement amount is 0.003 m with filler
3 (q u = 1.0 N/mm2). The area of influence ofsettlement in x-direction is -9.5 to 9.5 m. In the caseof injecting filler 1, 2 and 3, no settlement occurs
outside that area. When filler is injected, settlement
amount is less than 0.008 m, and settlement amountis greatly reduced as compared with when pullingout holes are hollow. It is because that stressconcentration on pulling-out holes can be prevented
by injecting the filler. Therefore, it can be said thatby fil ling the pulling-out holes, the settlement ofout holes are fixed with filler.
In that case, it shows that surrounding groundon the ground surface is deforming toward thecenter of the ground surface. It is because of thefiller is resistant to deformation due to the filler is
injected. So that, it can be said that x-direction
displacement is reduced by injecting the filler intothepulling-out
holes.
And,x-direction
displacement reduces as the strength of the filler.
From Figs. 4 and 5, the maximum settlement
amount is about 0.30 m in the part sandwiched by
the pulling-out holes when the pulling-out holes arehollow. It is because that the stress concentrates
around the pulling-out holes by excavation. The
area of influence of settlement in x-direction is -15
to 15 m and the ground surface rise in the outsidethat area. As downward stress acts by initial stressanalysis, downward stress is released by excavation
and upward stress acts, so it can be said to rise awayfrom the area of influence of settlement. As above,84

International Journal of GEOMATE, Feb., 2019 Vol.16, Issue 54, pp.81 - 85

N/mm2) and 3 (q u = 1.0 N/mm2) inject. Comparing
filler 2 (q u = 0.5 N/mm2) and filler 3(q u =1.0N/mm2), the settlement amount has almost
no difference, and there is almost no difference inthe area of influence of settlement. Therefore, it isdesirable to inject the filler of strength 0.5N/mm2 tothe pulling-out holes of existing piles inconsideration of economics.
As this study’s future work is that it is necessary
to examine the influence of this analysis comparedwith this analysis result when changing groundparameters, arrangement number of the pulling-out
holes, compounding materials for filler. And,identify the strength of filler generally required.

ground is suppressed. And the area becomes smaller
as the strength of the filler increases.
From Fig. 4, injecting filler 1 (q u = 0.1 N/mm2),
the settlement amount is locally large in the filler
part. It is because that the compressive stress acts
greatly from the surrounding ground on the filler
part due to the small filler strength. Comparing filler
2 (q u = 0.5 N/mm2) and filler 3 (q u = 1.0 N/mm2),
the settlement amount has only 0.001 m difference,and there is almost no difference in the area ofinfluence of settlement.
The filler of strength 0.5 N/mm2 is defined as thesame strength as the ground, which is prescribed in
the “Public Building Construction Standard
Specification (Building Work) [5]”, so it is adopted
as standard compound, in recent years. Besides it
there is no reason.
However, from the above, it is desirable to inject
the filler of strength 0.5 N/mm2 to the pulling-out
holes of existing piles in consideration of
economics.

5. REFERENCES[1] Takao M., Leaving the foundation pile,backfilling denied the defects of ground support
force of the part, agent of accountability
violation was also negative case, RETIO,
No.82, pp.166-167, 2011.
[2] Yasushi F., Futa N., Yasushi U., Keisuke T.,
Study on the Young's modulus of the fluidized
processing soil. Summaries of technical papersof annual meeting Architectural Institute ofJapan, pp.591-592, 2014.
[3] Yasushi F., Deformation properties of thebackfill material which has a fluidity and selfhardening, Town Value-up Management
report, No.37, pp.41-44, 2011.
[4] Marushin Co., Ltd., About the pulling out
method of the existing pile, Retrieved April 21,
2018, from http://marushinn.jp/handbook/[5] Ministry of Land, Infrastructure, Transport andTourism, Public Building Construction
Standard Specification (Building Work) 2013
Edition, MLIT, 2016.

4. CONCLUSIONSIn this study, the influence of the pulling-out
holes on surrounding ground was evaluated bythree-dimensional static FEM analysis fordevelopment of pulling-out of existing piles.
When the pulling-out holes are hollow, themaximum settlement amount is about 0.30 m in thepart sandwiched by the pulling-out holes. But, when
the pulling-out holes are fixed with filler thatstrength over 0.1 N/mm2, the settlement amount isless than or equal to 8 mm. And the area of influenceof settlement becomes smaller when the filler
injects into the pulling-out holes than when thepulling-out holes are hollow. Therefore, it becomes
clear that injecting the filler is an effective means tosuppress ground settlement.
In this study, the settlement amount is resulted
with locally large in the filler part when the filler 1(q u = 0.1 N/mm2) injects. And, it is possible toprevent local settlement when the filler 2 (q u = 0.5

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