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

Example of Construction of Sheet Pile Walls for Anti-Seismic Reinforcement ofRailway Embankment
Kazuyuki MATSUZAWAManager, Engineering Works Division, Sato Juki Corporation, Tokyo, Japan
Email: k.matsuzawa@satojuki.com

Kenichi SHIRASAKI
President, Sato Juki Corporation, Seiro-machi, Niigata, Japan

Seiji KONYA
Senior Executive Director, Tokyo office, Sato Juki Corporation, Tokyo, Japan

Yoshiteru SUZUKIManager, Piler Division, Kajikawa Construction, Tokyo, JapanABSTRACT
A construction of anti-seismic reinforcement of railway embankment was performed near Hirai Station in the JR Sobu
Line. The site was located in a densely populated residential area. The working space was limited to the width of theslope of the embankment. Each pile was cut by four and carried in by medium duty trucks for Koshin site. On the otherhand, a storage space for pile materials was prepared in Hirai site by using L-shaped sheet pile walls and excavation.
The standard press-in method was adopted for Koshin site in the preliminary design. But, since it was difficult to carryin additional equipment after press-in work had processed, it was decided to use a versatile machine, ECO400S, inpreparation for the probable hard ground which consisted of buried and abandoned materials in the embankment. ForHirai area, at the first pressing-in for temporally sheet piling, at 30 cm below the surface of embankment, the pile wasblocked by rubbles. As a result, crush pilers were used to construct both temporally and real structure of sheet pile walls.
The GRB system was used to perform sheet piling in narrow working space at the both Koshin and Hirai sites effectively.
Key words: GRB System, Narrow Space, Weld Joint, Versatile Piler machine

1. Outline of the project

GRB system with using a clamp crane, a unit runner and a

1.1. Place

pile runner was indispensable to the works.

Hirai is located in the east part of Tokyo. Fig. 1 shows

As mentioned above, it was difficult to carry in sheet

the location of the construction site. It is a densely

pile materials in sufficient length. Piles were carried in by

populated area centering on Hirai Station in the JR Sobu

divided materials. In Koshin site, because large-sized

Line. That is a main train line which connects Chiba tovehicles were regulated, each pile was cut into 4 pieces by

Tokyo, and many commuters use it. Along the railroad, alength less than 6.5 m. It was necessary to joint them byresidential buildings stand close together densely and are

welding during press-in procedure and there was apacked to the side of embankment. Except the main roads,concern that this would prolong the installation time. In

the large-sized vehicles were regulated in this area.

order to overcome this situation, working space for lateralwelding was prepared to joint upper pile with upper1.2. Background and objectives of the projectBecause the site was narrow, slender, and slope

middle pile, and lower middle pile with lower pile.

terrain, heavy machinery could not approach the piler. The

for one sheet pile decreased from 3 to 1.

Number of welding joints during the press-in procedure- 481 -

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

Fig. 1

Location of Construction Sites

2. Structural type and piling method

2.2. Ground condition
Fig. 3 shows the profiles of soil layers and SPT N-2.1. Site condition
In this site, the construction was performed adjacentvalues at the site. The railway embankment wasto the railway in service. A distance between the railway

constructed on a fine sand layer having thickness of twocenter of the inbound line and the planned sheet pile lineor three meters. A soft sandy silt layer having N-values ofis 5.1 m as shown in Fig. 2. Safe operation of the train wasalmost zero underlay it. Some results showed high N-

the top priority. A clamp crane, CB-3, was provided withvalues from the surface to the bottom of embankment due

swing limit control to prevent over turning toward theto buried debris such as concrete blocks, bricks and so on.

railway. However, every crane movement was restricted
only for one minute before the train passage. Trains passed

SPT N-value

ProfileProfile0 1020304050

at intervals of three minutes during the rush hour.

SPT N-value
0 1020304050

Fill
55FineSilty Sand

Fine Sand

1010Sandy
Silt
15

Depth (m)Depth (m)FillSandy
Silt15202025253030

SiltFig. 2Fig. 3

Cross-sectional view of Koshin site- 482 -Soil profiles and results of SPT

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

Fig. 4Cross-sectional view of the reinforcement structures of Hirai site

2.3. Structural type2.4. Piling method

Fig. 4 shows a cross-section of the reinforcement for

Table 1 shows the specifications of sheet piles usedthe embankment of Hirai site. A sheet pile wall and thein Koshin and Hirai site. The type IV sheet piles were usedexisting retaining wall were connected with tie wires

in Koshin site and the type VL sheet piles were used fortensioned in three tiers. Ground anchors were also used

Hirai site. The standard press-in method was adopted as awhere retaining wall did not exist. This was the same as inpiling method in the initial design for both Koshin andKoshin site.

Hirai sites. But, since it was worried that the embankment

The method using sheet piles was expected to reduce

contained some debris, augering equipment was preparedrisk of liquefaction by dividing the fine sand layer underin addition. The versatile piler machine was required

the embankment.

consequently.
In Koshin site, SCU-ECO400S, a versatile piler
machine was used for installation of type IV sheet piles. It

Table 1.

was able to convert from standard press-in to augering bySpecifications of sheet pile

simply removing the attachment.
Site name

Piletype

Pile
Length(m)Number ofdivision

Numberof pile

On the other hand, a similar versatile piler, SCUECO600S, was discussed in Hirai site, where the designed
sheet pile was type VL. It was compatible for simple press-

17.0
KoshinSP-IV

16.047418.5
TotalTokyoSP-VLside21.0
25.0

3
Total26.5Hirai
ChibasideSP-VL

23.0
16.0

3

17.5
Totalin and augering providing two respective chucking

151

apparatus. But it was difficult to carry the additional chuck403

apparatus together with the piler machine and to replace

601

them on pile installation site. The working platform in

61

Hirai site was not prepared for the entire construction area.

206

Therefore, the Crush piler, SCU-600 was used for pile267

installation in Hirai site. The crush piler usually282

synchronize and install sheet pile together with auger. The82

installation speed is slower than that of a standard press-in

106machine.

75

By the manufacturer’s efforts, the piler was enhanced

545

and it became possible to install sheet piles without
synchronization of augering. A short casing was used as- 483 -Proceedings of the First International Conference on Press-in Engineering 2018, Kochi

an attachment to chuck together with sheet piles. It was

3. Press-in pilingeasy to change operation mode of the piler from augering

3.1. Layout of Koshin site

to press-in. This helped much to reduce the construction
period.

Fig. 5 shows the layout of Koshin site. Sheet pileswere constructed over 240 m along the railway. The

As shown in Fig. 3, the silt layer below thedistance between the center of the nearest rail track andembankment was very soft and augering was not necessary.

the planned sheet pile center was 4.5 m. A working

Moreover, it was concerned that the resistance against

platform had been constructed having length of 180 m andextraction during press-in performance of subsequent pilewidth of 4 m. The border of the platform was located at

became insufficient and result in forward inclination of the1.5 m from the neighbor’s housing structures.

sheet pile. In order to overcome this problem, additional

The construction work was separated into three parts,

jack was provided at the front end of the piler machine.

(a) pile installation, (b) horizontal welding, (c) reception

The jack was mobilized when the piler extract the sheetof delivered pile materials.

pile during pile installation if necessary. As mentionedFig. 6 shows the flow of a series of construction work.

above, augering was necessary only for hard contents ofDue to the surrounding condition, the maximum length ofembankment in case that standard press-in was difficult.

carried in materials was limited to less than 6.5 m. The pile

Total 62 of 601 sheet piling required pre-augering insets were delivered after being cut into four and piled up

Koshin site. On the other hand, most of all piles, 793 of

by each set. They were loaded and conveyed by a pile

812 sheet piling required pre-augering in Hirai site.

runner to the welding yard. The cut parts were jointed andeach upper and lower part of one sheet pile set wasassembled. In order to secure linearity of welded pile, aResidential structures

(a)

(b)

(c)

Site
entrance

Delivery truck
Unloaded pile material

Fig. 5

Layout of sheet pile construction in Koshin site- 484 -Proceedings of the First International Conference on Press-in Engineering 2018, Kochi

series of frame stands equipped with leveling jacks were

3.2. Layout of Hirai siteused for the welding procedure.

Fig. 7 shows the layout of Hirai site. The site was on

Jointed upper and lower piles were loaded again to thepile runner and conveyed to the pile installation site. Theboth across the road. The upper figure illustrates the Tokyoside, and the lower illustrates the Chiba side.

piles were supplied by a clamp crane to the press-inmachine.

Temporaryworkingspacesformachinery

introduction and for pile material reception wereconstructed on each site in advance of main piling works.

Fig. 6

Working flow of piling procedure in Koshin site

Fig. 7

Layout of Hirai site

- 485 -

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

Fig. 8 shows temporary working space for Chiba sidesite. A rectangular space having width of 7 m and lengthof 40 m were constructed by means of an L-shaped sheet
pile wall using type IV sheet piles having length of 7 m,with the embedded depth after excavation was 3.5 m. The

Main sheet pile SP-VL
Temporary sheet pile SP-IV L = 7 m
Temporary working yard

first pile installation was carried out by the standard pressin. The piles were obstructed at 30 cm below the surfaceby debris. The piling method was changed to hard groundFig. 8 Temporary working yard for Chiba side site

piling using a crush piler, ECO400S. Photo 1 shows thepiling work for the temporary sheet pile wall. The sub
crane was protruded and set on the road.
3.3. Productivity
In Koshin site, total 601 sheet piles were required forthe construction in the period of seven months. The
average number of pile installation was four piles per day.
In Hirai site, two pilers were used for each of theTokyo side and the Chiba side. Total 812 sheet piles werecompleted in about 400 days; two piles per day.
3.4. Encountered difficulties
In order to reduce the construction period, two

Photo 1. Construction of temporary working yard

approaches were performed.
The first one was the horizontal welding performedin Koshin site. The welding time for one joint exceeded
one hour. Preparing upper and lower piles, jointed themseparately in the welding yard, thus reduced the numberof joint works during press-in procedure.
Another approach was to carry pre-boring only inshallow depth, i.e. depth of embankment. As shown in Fig.
9, auger was re-installed into bored hole beside acompleted pile and stood alone while the press-inFig. 9

Photo 2. Near the end point of construction (Koshin site)

Working flow of piling procedure in Hirai site- 486 -Proceedings of the First International Conference on Press-in Engineering 2018, Kochi

procedure was being performed. It is seen in Photo 2 that

conducted and sheet pile installation at that point was

the auger was stood between the piler and the clamp crane.

postponed for one month taking extra precaution. One

This measure enabled to carry auger assembly together

month later, pile installation was conducted again, and any

with the piler machine without a working space nearby.

further displacement was not observed.

Moreover, it could avoid the danger of falling down longtall auger to a narrow space by the clamp crane.
For a permanent structure, welding joint wasmanaged strictly in terms of its quality. Welders skill wastested at some initial welding stages under supervising by
the official. The test of welding for one weld joint
consisted of penetration test (PT) for the first pass, PT andultrasonic test (UT) for the last pass and again PT for
stiffening plate. These tests were conducted every 30 piles.
In addition, the welding supervision engineer was obliged
to stay resident in the site.
The embankment contained various unpredictableobjects. In this site, the piling was obstructed quite often.
Photo 3. Ultrasonic test ongoing

Photo 4 shows the exposed concrete structure after
excavation for the temporary yard. The augering waspartly interfered by the edge of the concrete and sheet piles
were installed with slight inclination. In the main
construction of the Tokyo side of Hirai site, a hard granite
fragment was removed from augering hole. Surface of thefragment was carved by the auger head as shown in Photo
5. Besides this, we encountered embedded reinforced
concrete and frequently the reinforcement twisted aroundthe auger head.
The narrowest part was at the nursery school in Fig.
7. In the preparation stage of Hirai site, the structure had
not been built yet and the ground was used as an open-air
car parking lot. The general contractor decided to rent thisspace during the construction period. Unfortunately, thePhoto 4. Concrete structure at the bottom of embankmentbuilding was constructed, and the distance between theexposed after excavation for temporary yard

wall of building and the sheet pile center was 2.5 m. It wasa minimum radius for a clamp crane to lift sheet piles
vertically and turn to the piler for pile installation. Usingan assist rope to prevent swaying of sheet piles, it barely
succeeded in making rotation of a clamp crane. (Photo 6)
In order to secure safety of the train operation,
displacement of the railway was monitored on a steadybasis. The maximum displacement of 7 mm occurred once
when boring near the back of the abutment. The limit
value of displacement for safe train service was 17 mmandthepredeterminedvalueforsuspensionofPhoto 5. Fragment of granite shows trace of auger headconstruction was 12 mm. The railway maintenance was- 487 -Proceedings of the First International Conference on Press-in Engineering 2018, Kochi

4. Concluding remarks
Sheet pile walls were used for reinforcement ofrailway embankment in Hirai, Tokyo. The site wassurrounded by residential buildings and had no sufficient
work space for sheet piling.
With adopting the GRB system operation, sheet
piling was conducted adjacent to the train in service. The
security for railway service was kept steady overconstruction period.
By reduction of weld jointing during the press-inprocedure, the cycle time was shortened.
Pre-augering and the standard press-in procedure

Photo 6.

Clamp crane slewing at the minimum radiusefficiently shortened the construction period.
It took two years to complete three sheet pile walls
consisting of total 1400 sheet piles.
5. Acknowledgements
Thanks to Giken staff for cooperation to enhance thecontrol system and to manufacture the optional jacksystem, series of the construction works have completed
in a shorter period.
References
JR East. 2016. Press release “About anti-seismic
reinforcement construction for railway embankmentin preparation for an earthquake beneath themetropolitan area”. (in Japanese)
Matsuzawa, K., Shirasaki, K., Konya, S. and Suzuki, T.
2018. Example of construction of sheet pile walls
using cyclicauger

methodfor

anti-seismic

reinforcement of railway embankment. Proceedingof the First International Conference on Press-inEngineering 2018, Kochi, (submitted).
Photo 7.

View of construction site from the platform ofHirai station- 488 -