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

A Study on Bearing Capacity of Steel Sheet Pile with Closed Section at Bottom
Supported in Intermediate Layer by Press-In Method
Kazuhide TODA
Researcher, Steel Structures Research Laboratories, Nippon Steel & Sumitomo Metal Corporation, Chiba, Japan
Email: toda.7ay.kazuhide@jp.nssmc.com

Shinji TAENAKA
Chief Researcher, Steel Structures Research Laboratories, Nippon Steel & Sumitomo Metal Corporation, Chiba, Japan

Hidetoshi NISHIOKA
Laboratory Head, Structures Technology Division, Railway Technical Research Institute, Tokyo, Japan

Taisuke SANAGAWA
Assistant Senior Researcher, Structures Technology Division, Railway Technical Research Institute, Tokyo, Japan

Naoyuki KITA
General Manager, Civil Engineering Technology Division, Obayashi Co., Tokyo, Japan

Kosuke MATSUURA
Chief, Civil Engineering Technology Division, Obayashi Co., Tokyo, Japan

ABSTRACT
Conventionally, steel sheet piles have been utilized as earth pressure resisting structures such as riverbank revetments,
seawalls, road retaining walls and temporary retaining walls by taking advantage of their excellent horizontal resistancecharacteristics. In recent years, it is also applied to structures expected for vertical bearing capacity. The "closed-end
steel sheet pile", which is expected to exhibit a higher vertical bearing capacity, has been developed by providing aprocessed and closed cross section of the front end portion of the steel sheet pile. In the Sheet Pile Foundation Method,it has been shown by previous studies that effective reinforcement of substructures can be achieved by using thisprocessed “closed-end steel sheet pile”. However, the bearing capacity characteristics when the “closed-end steel sheet
pile” is supported on the intermediate layer is unknown. Therefore, in order to grasp the bearing capacity characteristics
when the “closed-end steel sheet pile” was supported on the intermediate layer with SPT N value of about 30, thefull-scale load test was carried out. As a result, from the distribution of the axial force and the peripheral resistance, theresistance of the pile-end closed-section zone is sufficiently demonstrated, and it is estimated that the plug of thepile-end closed-section contributes greatly to the bearing capacity development.

Key words: Steel sheet pile, Bearing capacity, Loading test, Closed-end steel sheet pile, Sheet Pile Foundation

1. Introduction
Steel sheet piles have been in use over the years as

piles have also been increasingly used for applications

earth pressure resisting structures such as riverbank

PFS Method (Partial Floating Sheet-Pile Method) (Fig.

revetments, seawalls, road retaining walls and temporary1), in which the isolating effect of steel sheet piles is used,retaining walls by taking advantage of their excellent

has been proposed as a means of preventing thehorizontal resistance characteristics. With the growing

subsidence of surrounding ground resulting fromneed for seismic strengthening in recent years, steel sheet

embankment construction on soft ground. Steel sheetthat expect them to bear vertical loads. For example, the- 49 -

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

piles have also come into use for seismic strengthening

2. Full-Scale testof foundation structures. An example of such steel sheet
pile application is the Sheet Pile Foundation Method (Fig.

2.1. Ground condition
The tests were carried out at two places which in2), in which steel sheet piles and footings are structurally

Futtsu, Chiba Prefecture, and in Kochi, Kochi Prefecture

integrated so as to use the steel sheet piles to resist both

Japan. The standard penetration test results (SPT-N

horizontal and vertical loads. A previous study has shown

value) of the test ground are shown in Fig. 3. The

that an existing foundation structure can be effectively

intermediate layer at the Futtsu site consists of fine sandstrengthened against seismic loading by use of a steel

and has an N-value ranging from about 20 to slightly lesssheet pile that has a closed section at the toe of the pilethan 40. The intermediate layer at the Kochi site consists(closed-end steel sheet pile), which is designed tomainly of sand and gravel and has an N-value of 30 orachieve large vertical bearing capacity by providing amore at depths of 4 m or more. In the Kochi site, theclosed section at the toe of the steel sheet pile.

embedded length in the intermediate layer is longer than

However, although the vertical bearing capacity of

3Dp in the closed-section, but in the calculation of thethe closed-end steel sheet pile on the bearing layer

end bearing capacity, only the 3Dp section of thehaving an SPT N-value of 50 or more has been verified,closed-section was considered.

the vertical bearing capacity in an intermediate layer is

0

10

SPT-N value
20 30 4050

0Steel sheet pile

Filling soil
1characteristics are likely to vary depending on ground2

conditions. In this study, a series of full-scale loading

Fine sand3

tests was conducted for a total of four cases tested at twosteel sheet pile installed into an intermediate layer having

4
5

Silt

6

an N-value of about 30.

Intermediate
later

7

Fine sand

9
10

11

Bank

5Dp
(= Closed section length)

3Dp(= Embedded length)8

Pile head connection

Area forend bearing capacity

Depth (m)sites to evaluate the bearing capacity of a closed-end

Area forfrictional bearing capacity

yet to be determined. In addition, bearing capacity(a) Futtsu (Case1, Case2)

Soft ground

SPT-N value

Floating Sheet pile

0

10

20

30

40

50

0
1

2

Fig. 1 PFS Method（Partial Floating Sheet-Pile Method）

Gravel3

Area forfrictional bearing capacity

Steel sheet pile

Bearing stratum

Fine sandEnd bearing Sheet pile4

Combined footing
Steel sheet pile

6

Gravel7

7Dp(= Embedded length)

8
9
10

11

Closed-end steel sheet pile

12
13

Existing pileFig. 2(b) Kochi (Case3, Case4)

Sheet Pile Foundation Method

Fig. 3and closed-end steel sheet pile

- 50 -SPT-N value

3Dp(= Closed section length)

Existing footing

Intermediate
later

Area forend bearing capacity

Depth (m)5

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

2.2. Test parameters

Table 2.

Test specimens for full-scale test

2.2.1. Closed-end steel sheet pile
To form the closed section at the toe of the pile, theCasesame type of steel sheet piles as main piles, which has

Pile type

10H

25H

shorter longitudinal length than the main pile, is welded

Case1

Site

Case2
FuttsuWidth0.900m0.900malong the interlocks. In full-scale tests, the hat-shapeAp

0.234m2

0.300m2

steel sheet piles called 10H and 25H were used. Table 1

Dp

0.48m

0.55m

2.40m (= 5Dp)

2.75m (= 5Dp)

Embedded length

1.50m (= 3Dp)

1.50m (= 3Dp)

Shape of pile-end closed section

Case

Case3

Case4

（view from the bottom）

Site

shows these piles.

Closed-section
lengthTable 1.
Pile type

Closed-end steel sheet pile

900mm

230mm

10H
weldedclosed section

Kochi

Pile type

10H

10H

Width

900mm

900mm

Ap

0.234m2

0.234m2

Dp

0.48m

0.48m

1.50m (= 3Dp)

1.50m (= 3Dp)

3.50m (= 7Dp)

3.50m (= 7Dp)

Closed-section
length

900mm
300mm

Embedded length

25H

Dp = √ Ap
weldedApclosed section

2.2.2. Tests parameters
The test specimens used in the full-scale test are

Fig. 4Equivalent pile width of steel sheet piles

summarized in Table 2. The equivalent pile width islength of square sections whose area (= Ap) is calculated

2.3. Full-scale pile installation test
The test specimens were installed into the ground by

as the summation of the area surrounded by two steel

the press-in method, which is a low-noise, low-vibration

sheet piles welded together and the plate thickness at thepile-installation method that can be used at a site withbottom.

limited overhead clearance. The water jet was also used

represented as Dp (Fig. 4). Dp corresponds to the side

According to Nakayama (2012), in the case where ato facilitate installation operation. The pile- installation

closed-end steel sheet pile is embedded into a bearing

procedures are shown in Table 3, and the relationshiplayer having an N-value of 50 or more, vertical bearing

between press-in force and depth is shown in Fig. 5.

capacity almost comparable to that of a steel sheet pile

In Case 1 and Case 2, water jet pressure wasthat has closed-section construction over the entire length

reduced to the idling level (1.1 MPa) at a depth of 1.0 m

can be achieved if the pile-end closed-section is designed

above the target layer (GL−6.0 m) so as not to disturb theto have a length of 3Dp or more. In accordance with thisintermediate layer into which the pile was to befinding, a pile-end closed-section length of 3Dp was used

embedded (target layer). Then, the pile was pressed inin Case 3 and Case 4. In Case 1 and Case 2, a pile-end

further until it reached the specified depth (GL−7.5 m),

closed-section length of 5Dp was used because theand the final press-in force was applied to complete thethickness of the layer having an N-value of 30 or moreinstallation operation.

was only 1.5 m (=3Dp).
- 51 -

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

In Case 3, the original plan was to embed the pile
into a bearing layer (GL−12.0 m) having an N-value of

2.4. Full-Scale load test
A full-scale loading test was conducted to evaluate

50 or more and stop the pile-end at GL−13.5 m. The

the bearing capacity characteristics of the closed-end

pile-end closed-section, therefore, was designed to have asteel sheet pile embedded into an intermediate layer

length of 3Dp. However, the water jet was not able towithout installation it into the bearing layer.

perform as effectively as expected because consistentwater pressure could not be maintained. Installation the0

Press-in force (×10 kN)
10
20
30
40

50

0

0

pile by a depth of 1.5 m from GL−6.0 m took more than
30 minutes, and further penetration became no longer

1

possible at GL−7.5 m, which was shallower than the

2

2

3

3

target depth, and press-in and pull-out operations were1

① Press-in force② Pull-out force

Depth (m)the water jet at high pressure (15 MPa) until reaching theDepth (m)target depth. It was decided, therefore, to continue using

Press-in force (×10 kN)
10
20
30
40

50

0

4

① Press-in force② Pull-out force

4

repeated. In view of the Case 3 results, the plan for Case5

5

4 was altered so that the pile was embedded into an

6

6

7

7

8

8

intermediate layer (GL−6.0 m) and pressed in until itreached a target depth of 7.5 m. Since the steel sheet piletended to lean toward the water jet equipment during thepress-in operation, in Case 4 the water jet equipment was(a) Case1(b) Case2

positioned separately at opposite locations as shown in
Fig. 6. In Case 4, water jetting was used until the target

0

Press-in force (×10 kN)
10
20
30
40

50

0

0

depth was reached as in Case 3. The time required for① Press-in force② Pull-out force

advancing the pile by a depth of 1.5 m from GL−6.0 m

1

was about 15 minutes, which is half the time required in

2

2

3

3

Case

Installation conditions

Depth
Surface sand layer(GL-0.0～5.0m)

Case1
(10H)

Intermediate layer(GL-5.0～7.5m)
GL-7.5m
Surface sand layer(GL-0.0～5.0m)

Case2
(25H)

Intermediate layer(GL-5.0～7.5m)
GL-7.5m
Surface sand layer(GL-0.0～2.0m)

Case3

Gravel layer

Case4(GL-2.0～5.0m)(10H)Intermediate layer(GL-5.0～7.5m)
GL-7.5m

Installation conditions
Water pressure (5.0MPa)

1Depth (m)Table 3.

Depth (m)Case 3.

Press-in force (×10 kN)
10
20
30
40

50

0

4

4

5

5

6

6

7

7

8

8

Water pressure (1.1MPa)① Press-in force② Pull-out force

Final press-in load (470kN)(c) Case3
Water pressure (5.0MPa)

Fig. 5(d) Case4

Relationship between press-in force and depth

Water pressure (1.1MPa)

Main pile
Water jet

Final press-in load (490kN)

Water jet

Water pressure (3.7MPa)

Water pressure (～14.7MPa)

Attached pile(a) Case1, Case2, Case3

Water pressure (1.1MPa)

Fig. 6
Water pressure (15.0MPa)- 52 -(b) Case4

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

2.4.1. Test procedures
The full-scale loading test consisted of a rapid(≦6000)(gravel)(1)・Frictional resistancerfk = wjr × 3 N (≦40)

loading test and a static loading test. Both load tests were(sand or gravel)(2)

carried out when 33 to 43 days had passed since thewhere qtk is intensity of the end bearing capacity

completion of the installation tests. The test method is(kN/m2); rfk, intensity of the frictional resistance (kN/m2);

based on the standard method provided by the Japanese

βwjq, βwjr, reduction due to water jet (= 1/3); and N, SPT

Geotechnical Society (2002).

N-value at the tip of the steel sheet pile.

At the Futtsu site, the rapid loading test was
conducted. In the test, a 260-kN-weight was dropped

Also, in the calculation of end bearing capacity, Ap
shown in Fig. 4 is defined as the tip closure area.

from 14 different heights ranging from 21 cm to 281 cm

Fig. 7 shows the rapid loading test results in Case 1

for the type 10H piles and from 12 different heights

and Case 2, along with the maximum unloading point

ranging from 25 cm to 285 cm for the type 25H pile (lastresistance results obtained by the unloading point method

three drops from the same height). For both types of piles,(Japanese Geotechnical Society (2002)). Table 4 shows

the arrival at the 10%-of-pile-diameter subsidence level

the pile-head and pile-end bearing capacities at 0.1Dp. In(0.1Dp) was confirmed at the end of the loading test.

the test specimen used in Case 1 shown in Fig. 7 (a), a

At the Kochi site, the static loading test wasmeasured unloading point resistance of 722.9 kN was

conducted. Loading was carried out as a seven-cycle

obtained at 0.1Dp (= 48 mm), and after the tendency ofprocess, and the maximum loads applied during theresistance to increase was observed, a maximum

seven cycles were 200 kN, 400 kN, 600 kN, 800 kN,

unloading point resistance of 920.0 kN was observed

1,300 kN, 2,000 kN and 2,100 kN. It was made a rule toduring the 12th cycle. In Case 2 shown in Fig. 7 (b), a

increase the applied load at a rate of 50 kN/min andmaximum unloading point resistance of 1,028.6 kN was

decrease it at a rate of 100 kN/min. Holding time forobserved during the 10th cycle. After that, resistanceeach loading step was as follows: a constant period noshowed a tendency to decrease, and then 948.4 kN wasless than 30 minutes of new loading steps, a constantobserved at 0.1Dp (= 55 mm). As shown in Table 4, theperiod no less than 2 minutes of unloading or reloading

bearing capacity at 0.1Dp was about 15 times and 20

steps and a constant period no less than 15 minutes oftimes the final press-in load in Case 1 and Case 2,

unloading to zero load before moving on to the next

respectively.

loading stage. In Case 3, the 10%-of-pile-diameter

From the strain gauge installed in each test

subsidence (0.1Dp) was reached during the fifth cycle,
cycle to end the test. The maximum load reached in thetest was 2,000 kN in Case 3 and 2,100 kN in Case 4.

Load (kN)and in Case 4, 0.1Dp was reached during the seventh

2.4.2. Loading test results

2000
1800
1600
1400
1200
1000
800
600
400
200
0

Load (kN)a closed-end steel sheet pile. The proposed formulas are

pile when the pile-end displacement has reached 0.1Dp
against vertical load. The proposed formulas are as

2000
1800
1600
1400
1200
1000
800
600
400
200
0

40
60
80
Displacement (mm)

100

120

－ Load-displacement relationshipMaximum resistance ○ Unloading point resistance:1028.6kN
0.1Dp resistanceSame drop height:285cmEstimated bearing capacity0follows:
・End bearing capacity
qtk = wjq × 105 N

20

Maximum resistance: 920.0kN(a) Case1

proposed formulas for calculating the bearing capacity ofbearing capacity is defined as the resistance force of a

0.1Dp resistance
Estimatedbearing capacity0

2.4.2.1. Comparison with estimated bearing capacity
Railway Technical Research Institute (2014)

based on various full-scale loading test results. The－ Load-displacement relationship○ Unloading point resistance

20

40
60
80
Displacement (mm)

100

120

(b) Case2(≦4000)(sand)

Fig. 7- 53 -

Relationship between vertical load and displacement

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

specimen, a graph showing the depth distribution of axial

Table 4.

force was prepared, and the results corresponding toCase

0.1Dp and the maximum resisting force were compared.

Bearing capacity

722.9

kN

And, the axial force of the pile-head was taken as theEnd bearing capacity

630.2

kN

87.2

%

Loading test results
0.1Dp resistanceunloading point resistance calculated from the strain

Case1

Ratio of End bearing capacity

gauge at the part protruding from the ground surface. In(10H)

to Bearing capacity

the evaluation of end bearing capacity, as shown in Fig. 3,

Bearing capacity

the axial force at the section for 3Dp above the pile-end/ Final press-in force

was taken as the tip resistance. In the axial force

Bearing capacity

948.4

kN

distribution graph for Case 1 shown in Fig. 8 (a),End bearing capacity

775.5

kN

81.8

%

15.4

resistance was seen to increase from the 0.1Dp level to

Case2

Ratio of End bearing capacity

the maximum unloading point resistance level. The ratio(25H)

to Bearing capacity

between end bearing capacity and pile-head resistance,

Bearing capacity

however, did not change significantly, ranging from

/ Final press-in force

about 83% to 87%. In Case 2, as shown in Fig. 8 (b), theBearing capacity

1178

kN

Case3

End bearing capacity

385

kN

(10H)

Ratio of End bearing capacity

32.7

%

Bearing capacity

1812

kN

Case4

End bearing capacity

859

kN

(10H)

Ratio of End bearing capacity

47.4

%

end bearing capacity did not change, indicating that thetendency of resistance to decrease from the maximum
unloading point resistance level to the 0.1Dp level shownto Bearing capacity

in Fig. 7 (b) is due to changes in frictional resistance. In
both cases, it can be clearly seen that resistance in theintermediate layer into which the pile-end was embedded
increased sharply. From this, it can be inferred thatto Bearing capacity

although the pile was supported by an intermediate layer,
resisting force occurred mainly in this region so that the0bearing capacity.

12

and Case 4. Fig. 10 shows the depth distributions of axial

3

Depth (m)Fig. 9 shows the static load test results in Case 3

first limit resistance is estimated to be 500 to 800 kN,

4

200

400

600

800

1,000

1,200

Axial force distribution
at 0.1Dp

0.5m
0.5m
0.5m
2.0m

Axial force distribution
under maximum resistance

2.5m

5
1.0m

6

and a measured second limit resistance of 1,178 kN was

7

recorded at 0.1Dp (= 48 mm). In Case 4, first limit

8

3Dp Embedment
into intermediate layer

resistance was estimated to be 1,000 kN, and a measured

1.0m
0.5m

(a) Case1

second limit resistance of 1,812 kN was recorded at
0.1Dp (= 48 mm), which is greater than in Case 3 by aStrain gauge

Axial force (kN)00

and gravel ground, too, the estimated level of bearing

1

capacity can be achieved in a bearing layer that has an

2

SPT N-value of 50 or more. In all cases, resistance3

Depth (m)factor of about 1.5. It was also confirmed that in the sandtended to continue to increase after 0.1Dp was reached.

Strain gauge

Axial force (kN)0closed-end steel sheet pile effectively contributes toforce and frictional resistance. From Fig. 9, in Case 3,

19.4

4

200

400

600

800

1,000

1,200

Axial force distribution
at 0.1Dp

0.5m
0.5m
0.5m
1.0m

3.5m

Axial force distribution
under maximum resistance

5
1.0m

6

2.4.2.2. Bearing capacity depending on shape of sheet

3Dp Embedment
into intermediate layer

7

piles

8

As shown in Table 4, the end bearing capacity in the
25H case (Case 2) was greater than that in the 10H case- 54 -(b) Case2
Fig. 8Relationship between axial force and depth

1.0m
0.5m

Proceedings of the First International Conference on Press-in Engineering 2018, Kochi(Case 1) by a factor of about 1.2, which was similar tothe steel sheet pile was reduced. This resulted in reduced

the pile-end closed-section area ratio (Ap). Frictionaluse of water jetting, a reduced number of repetitions ofresistance was greater than in the 10H case (Case 1) by apress-in and pull-out operations, and reduced groundfactor of about 1.5, which was greater than the

disturbance mainly in the pile-end zone.

cross-sectional perimeter ratio of 1.1.
2.4.2.5. Comparison with the loading test results of
2.4.2.3. End bearing capacity depending on length ofprevious
Fig. 11 shows the relationship with the loading test

closed section
In the full-scale test, in which the pile wasresults obtained from steel sheet piles embedded into

embedded into an intermediary layer without installing it

bearing layers having an SPT N-value of 50 or more

into the bearing layer, the length of the pile-end

reported by the Railway Technical Research Instituteclosed-section

wasvarieddependingonground● Case3 (Bearing capacity), ○ Case3 (End bearing capacity)● Case4 (Bearing capacity), ○ Case4 (End bearing capacity)

2000

conditions. As can be seen from Fig. 7 and Fig. 9, the1800

estimated bearing capacity can be achieved by using 5Dp
Bearing capacity (kN)1600

for a sand layer and 3Dp for a sand and gravel layer.
Therefore, this estimation formula is on the safety side
(lower side). And from Fig. 8, the increase in axial force
is small within the range of 3Dp to 5Dp in the pile-end

1400
1200
Estimated bearing capacity

1000
800
600
400
200

closed-section, and does not contribute much to the pile

0.1Dp

0
0

tip plugging. Whether 3Dp, which is similar to the value
reported in a previous study focusing on a bearing layer

Fig. 9Estimated end bearing capacity

50100
Displacement (mm)150

Relationship between bearing capacity andhaving an N-value of 50 or more, may be applied to adisplacement

sand layer needs to be determined by checking on

0

500

1000

1500

2000

0

bearing capacity characteristics through further load00

testing.

1

1

2

2

3

3

100

200

300

of water jet
In Case 3, in which a pile installation challenge was

200kN

4

400kN
600kN

5

Depth (m)2.4.2.4. Bearing capacity depending on arrangement

Depth (m)

200kN

7

1300kN

4

7

2000kN

8

Axial force (kN)
5001000 1500

0

2000

0

in which water jet equipment was positioned at opposite

00locations to facilitate pile installation work, significant

11frictional

pile-end22closed-section zone as shown in Fig. 10 (b) so that its

3

3

200kN
400kN
600kN
800kN
1100kN
1300kN
2000kN
2100kN

4
5
6

bearing capacity in Case 4 is greater than that in Case 3

7by a factor of greater than 2. The reason for this is8

Area for end bearing capacity

thought to be that because the water jet equipment was- 55 -

400kN
800kN
1100kNsignificant difference in end bearing capacity: the end

installed at opposite locations in Case 4, the leaning of

300

600kN

Depth (m)roughly 50%. Also, as shown in Table 4, there is a

Frictional force (kN/m2)
100
200
200kN

Depth (m)ratio of end bearing capacity to bearing capacity was

Area for end bearing capacity

8(a) Case3

capacity decreased to about 30%. In contrast, in Case 4,

the

2000kN

6

Area for end bearing capacity

in Table 4, the ratio of end bearing capacity to bearing

by

1100kN

1300kNshallower depths as shown in Fig. 10 (a), and, as shownachieved

800kN

51100kN

6

part of the pile was smaller than at GL−6.0 m or

was

600kN

800kN

encountered, the frictional resistance of the embedded

force

400kN

4

1300kN
2000kN
2100kN

5
6
7
8

Area for end bearing capacity(b) Case4
Fig. 10

Depth distribution of axial force and frictional forceProceedings of the First International Conference on Press-in Engineering 2018, Kochi(2014). As can be seen from Fig. 11, the relationshiphaving an SPT N-value of 50 or more, confirming thatwith the expected bearing capacity in the cases where thethe achieved bearing capacity is comparable to thesteel sheet pile is embedded into an intermediate layer

expected bearing capacity.

having an N-value of around 30 is similar to theLength requirements for the pile-end closed-section

relationship in the cases where the steel sheet pile isvary depending on the ground conditions involving theembedded into a bearing layer having an N-value of 50

target layer, and the required lengths for a sand layer andor more.

a sand and gravel layer are 5Dp and 3Dp, respectively. In
3500

●
●
●
●
○
○
□

3000

Estimated (kN)

2500
2000

cases where water jetting is used to assist in pile

Case1 (10H (Intermediate layer, Futtsu))
Case2 (25H (Intermediate layer, Futtsu))
Case3 (10H (Intermediate layer, Kochi))Case4 (10H (Intermediate layer, Kochi))(10H (Bearing layer))(25H (Bearing layer))(IVw (Bearing layer))installation, it is advisable to reduce water pressure to theidling level at a depth 1 m above an intermediate layer so
as to minimize the disturbance of the target layer. In
cases where water pressure is difficult to maintain1500

because of ground conditions, pile installation resistance1000

increases if the steel sheet pile being installed leans
Case4
Case3
Case1 Case2

500
0
0

sideways. In such cases, ground disturbance around thepile-end during embedment operation may affect bearing

500 1000 1500 2000 2500 3000 3500

Measured (kN)capacity development. It is therefore necessary to takeFig. 11 Comparison with the past of loading test results

some corrective measures such as positioning water jet
equipment at opposite locations.

3. Concluding remarks
To evaluate bearing capacity characteristics of aclosed-end steel sheet pile embedded into an intermediate

References
Society for Study Group of PFS Method. 2005. PFS
Method technical data.

layer, a series of full-scale pile-installation and loading

Railway

tests was conducted at two sites.

Technical

Research

Institute,

Obayashi

Closed-end steel sheet piles were installed into the

Corporation, Nippon Steel & Sumitomo Metal

ground by the press-in method used in conjunction with

Corporation. 2014. Design and construction manualwater jetting. At the sandy soil site, water jet pressure

for sheet pile foundations applied to railway

was reduced to the idling level at a depth 1 m above thestructures (draft), 3rd ed. (in Japanese)intermediate layer before embedding the pile into the

Nakayama, H., Koda, M., Nishioka, H., Sanagawa, T.,intermediate layer. At the sand and gravel site, water

Harata, N., Kato, A., Toda, K. 2012. Static load test

jetting was used until the pile reached the target depth.

on vertical bearing capacity of steel sheet piles with

Installing water jet equipment at opposite locations

closed section, 9th Int. Conf. on Testing and Design

around the pile reduced press-in resistance and the time

Methods for Deep Foundations.
Japanese Geotechnical Society. 2002. Standard forrequired for reaching the embedment layer.

vertical load tests of piles.

Axial force and frictional resistance distributions
confirmed that even in the cases where the pile was

Railway Technical Research Institute. 2012. DesignStandard

embedded into an intermediate layer without installationforRailway

Structures(Foundation

Structures), Maruzen. (in Japanese)

it into the bearing layer, the embedded pile-end
closed-section zone served as a major contributor to

Toda, K., Nishioka, H., Sanagawa, T., Taenaka, S.,

resistance so that the closed-end steel sheet pile

Otsushi, K., Kita, N., Matsuura, K. 2016. Evaluation

effectively contributed to bearing capacity. Even in theof bearing capacity of steel sheet pile with closed

cases where the pile was embedded into an intermediate

section at bottom supported in intermediate layer

layer without installation it into the bearing layer, thebasedexpected level of bearing capacity was achieved as in thegeotechnical engineering symposium, pp. 255-260.

case where the pile was embedded into the bearing layer- 56 -

onloading

test

data,

60th

Japanese