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

Piling Tests and Induced Surface Settlement of Rotating Static Pressure SteelPipe Pile in Shanghai Soft SoilYingjun ZENG
Shanghai Urban Construction Municipal Engineering (Group) Co., Ltd., Shanghai 200065, China
Email: 18817366859@163.com

Chenhui LIU
Department of Civil Engineering, Technologiepark 905, Ghent University, Ghent 9052, Belgium

Liankai ZHANG
Shanghai Urban Construction Investment and Development Co., Ltd., Shanghai 200032, China

ABSTRACTThis paper presents a series of piling tests of rotating static pressure steel pipe pile including the pile length design inShanghai soft clay. The construction technology was examined by extensive field data of surface settlement during theconstruction. It was found that the vertical displacements of the surrounding soil were well controlled with a maximum
value of 5 mm. The static pressure rotary method can be applied in various geological and environmental conditions,especially in the case of river embankment, short distance protection piles, complex strata and low clearance. This
construction method can prove to be the valuable reference for mitigating risks of construction to adjacent structures insimilar soft soil geotechnical engineering project.
Key words: Rotating static pressure, steel pipe pile, soft soil disturbance1. Introduction
With the rapid development of infrastructure facilities,

technology may not meet the requirements of theparticularly in Shanghai, during the past two decades,

use of rotating static pressure steel pipe pile technology

more and more underground structures and metroin China, a series of piling tests including the design for

stations accompanied with excavations are increasingly

pile length were conducted, and the short constructioncarried out in congested urban areas. The soft soil induration and low impact on environment are described.

foundation pit engineering. In this paper, based on first

Shanghai is classified as very soft soil with high watercontent, low strength and low permeability. In such

2. Outline of the project

circumstances, the deformation control and the predictionof the effects of excavations on surrounding and2.1. Place
The test location was the Jinze warehouse ofstructures, and necessary protection countermeasures toShanghai Urban Construction Municipal Engineering

mitigate any adverse situation, are of great concern. The(Group), Qingping Road 9623 in Shanghai.

traditional construction technology for foundation pit
support in Shanghai mainly includes: bored pile + pile2.2. Background and objectives of the projectwater-stop curtain sprayed with high pressure; open

The soil deformation characteristics andcaisson; diaphragm wall + water-seal drapery; SMW

environmental impact induced by the equipment inprocess pile; and some other less used construction

Shanghai soft soil were expected to gain by the pilingtechnologies. In the very sensitive areas for environment

tests.

andsurrounding

buildings,

theaforementioned- 517 -theProceedings of the First International Conference on Press-in Engineering 2018, Kochi

3. Structural type and piling method
3.1. Site condition
No existing structures can be found around the test

Lubrication system

location.
3.2. Ground condition
Design methodology of this test was mainly based

Steel pipe piles

on parameters evaluated from field and laboratory testingElectricwelding
machineof soil through vertical core drilling. Different in-situ andlaboratory testing was carried out to get a realistic valueof the geotechnical properties of the soil encountered.
Details of Standard Penetration Test (SPT) of soil profilein the location are presented in Fig. 1.
Counter weight

Counter weight

SILENT PILER
Repair box
POWER UNIT

Materialyard for
Steel pipe
pilesElectric box

Fig. 1 SPT results of soil profile

3.3. Piling method
The static piling methods include standard press-in,press-in with water jetting, press-in with augering androtary cutting press-in. The adopted method here wasrotary press-in with water lubrication.
4. Press-in pilingFig. 2

Layout of the piling work

4.1. Layout
Fig. 2 shows the layout of the piling work.

4.2. Piling data and the design for the pile length
The tests were performed on 4 steel pipe piles, withthe diameter of 1m, thickness of 14 mm, pile spacing of
1.2 m, and four lengths of 6 m, 10 m, 10 m and 36 m.

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

The maximum rotating force is 100 kN·m, and thestratum;

maximum pulling force is 400 kN·m. The calculationd is the outer diameter of steel pipe pile.

process for design is as follows.

The counter weight of base for counterforce was

In the standard projects, when steel pipe pile isinitially pressed, the counterforce is usually provided by
the completed steel plate piles. The present tests
optimized the process, being the maximum counterforce
gradually provided through progressive length of steel
pipe pile.
According to the article 5.3.7 in Chinese Standard,
Technical Code for Building Pile Foundation (JGJ
94-2008), the following Eq. (1) was used for determining
the vertical ultimate bearing capacity of steel pipe pile bytheempiricalrelationshipbetweenthecalculated byW1  2  Quk  W2  Quki (2)where W1 is the counter weight of base with the safety
factor of 2; Quk is the side resistance of pile that is inconstruction; W2 is the weight of equipment; Quki is
the side resistance of completed pile.

physical

The counter weight of base and the length of pileparameters of soil and the parameters of pile bearing

can be determined by the above formulas without

capacity.

considering the influence of lubrication system, see Fig.

Quk  Qsk  Qpk  u  qsik li  p qsk Ap

3 and Table 1 for more details.

(1)

Steel pipe
piles

If hb / d＜5 , p  0.16hb / d ;If hb / d  5 , p  0.8 .

Depth[36m]Depth[10m]Where qsik is the standard value of ultimate side

Depth[10m]resistance of pile for the i layer soil, the same value as
the precast concrete pile;

Depth[6m]qsk is the standard value of ultimate tip resistance ofpile, the same value as the precast concrete pile;p is the coefficient of plugging effect of pile tip,p  1 for the closed steel pile;
SILENT PILERhb is the penetration depth of pile tip into the bearing- 519 -Fig. 3

Depth design of the steel pipe piles

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

Table 1.

Frictional resistances of the test piles and counter weight of basefS of the precast pile

Layer/kPathickness/mSilty clay

15

Silty clay with mud

Soil name

6m pile10m pile

36m pile

3.4

3.4

3.4

3.4

15(≤6m)

5.2

1.4

5.2

5.2

Clayey silt

30

1.8

1.2

1.8

1.8

Clay with mud

25

7.44

7.44

Silty clay

40

7.2

7.2

Silty clay

70

3.5

3.5

Sandy silt

100

2.3

2.3

Silty sand

110

5.16

5.16

Qsk /kN

361.1

631.1

4169.92

Qpk /kN

102.5

156.7

331.58Weight of SILENT PILER/Tons

32.5

32.5

32.5

361.1

4397.16

The friction force of completed pile/kN
Required counter weight (Safety factor =27.82)/Tons

20.4

According to the geological survey report, the pile

provided by the first three completed steel pipe piles islength of the test pile was determined through the above

much larger than the maximum static pressure of thecalculation, and the drag reduction effect of the waterequipment, the largest length of the fourth pile is set to be

lubrication system was not considered. The length of the36 m.

first test pile is 6 m, the required counter weight of baseis 27.8 Tons; The length of the second test pile is 10 m,
the required counter weight of base is 20 Tons; The

4.3. Construction flowcharting
The general construction flowcharting of the tests islength of the third test pile is 10 m, the required countershown in Fig. 4.

weight of base is 20 Tons. Since the counter-force- 520 -Proceedings of the First International Conference on Press-in Engineering 2018, Kochi

Ground leveling and hardening

Orienting location and laying line

Trench excavation

Hoisting of steel pipe piles

The piles were transported to sites

Setting of counter weight (orsteel sheet pile construction)

Installation of steel pipe piles

Press-in piling byspecified number
Removing the counter weightfor counterforce

Completing initial press-in

SILENT PILER walking

Successive construction

Clamping completed piles

Hoisting of steel pipe piles

The piles were transported to sites

Pile driving to designated elevation

Fig. 4 Construction flowcharting of the tests

4.4. Productivity
The time or efficiency for working procedures is4.5. Encountered difficulties
A difficulty was encountered during the pilingshown in Table 2. It can be found that the rotating staticprocess. Because the first three piles were short, whenpressure steel pipe pile technology can effectively

the fourth steel pipe pile was rotated and pressed into theimprove construction speed and reduce construction cost.

field, the equipment of SILENT PILER twisted around.

However, if the welding efficiency of the steel pipe can

When it happened, we reinserted the steel pipe pile, orbe improved, the construction duration of single pile will

adjusted the plane position and the pushing speed of thebe effectively improved.

steel pipe pile, so that the chuck of the press-in
equipment was axially fixed relatively.
Table 2.

Working

Hoisting of steel pipe

procedures

pileTime or efficiency

15min

Information for construction productivity

Press-in
1.5m/minAbutting
joint
15min

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Welding
1hVelocity ofSILENT PILER

press-inwalking

1.5m/min

15minProceedings of the First International Conference on Press-in Engineering 2018, Kochi(1) In soft soil areas, the construction of rotating static

5. Surface settlement data during piling
As shown in Fig. 5, five settlement monitoringpressure steel pipe pile has a small influence on thepoints with specified distances were arranged on bothsurrounding environment, and also can fulfill thesides of the 36 m pile during piling.

requirement of low noise and vibration. The steel pipe
pile can be removed by "pulling" type machine, toSteel pipe piles

DB-1

DB-2

DB-3

DB-4achieve resource recycling.

DB-5(2) If the welding efficiency of the steel pipe can be
improved, the construction duration of single pile will be

Legend：Settlement monitoring points

effectively improved.
7. Acknowledgements
The second author acknowledges the financial
support from the Mobility Fund of Ghent University.
References
Chinese Standard. Technical Code for Building Pile

SILENT PILER

Fig. 5

Foundations (JGJ 94-2008).

Layout of the settlement monitoring points duringpilingFig. 6 presents the change of surface settlement
curves with time. It can be seen from the figure that themaximum surface settlement was 5 mm without obvious
subsidence or uplift during the construction of staticpressure steel pipe pile with SILENT PILER (F401).
Considering the acceptable measurement errors, thedisturbance of steel pipe pile construction on surrounding
soil is small, and it may be applied in the densely built
areas with strict settlement requirements.
Time/day
Second day

Third dayForth day

Sixth dayTenth dayVertical settlement/mm

0-1-2-3-4-5-6Fig. 6DB-1
DB-2
DB-3
DB-4
DB-5

The change of surface settlement curves with time

6. Concluding remarks
From the above piling work, the following
conclusions can be drawn:- 522 -