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

Use of Press-in Piling Data for Automatic Operation of Press-in Machines andEstimation of Subsurface Information
Yukihiro ISHIHARAManager, Press-in Technologies Support Department, GIKEN LTD., Tokyo, Japan
Email: ishihara@giken.com

ABSTRACTThe Press-in Method is a piling technique that installs piles with a static jacking force, while gaining a reaction force
from previously installed piles. It generates less noise and vibration, and requires less space for construction. Anotherfeature is that it is possible to obtain piling data for each pile. It has been expected that this feature can be utilized as aconstruction technique supported by ICT (Information and Communication Technology) to enhance the rationality ofthe design and construction of the structures with piles. This paper summarizes the present situation of two techniques
to utilize the press-in piling data, which were registered with NETIS (New Technology Information System) in Japan in
2017. One is the automatic operation of a press-in machine and the other is the estimation of subsurface information.
Key words: Press-in piling data, Automatic operation, Estimation of subsurface information

1. Introduction
1.1. Outline of the Press-in Method
The Press-in Method is one of the pile jacking
methods that use a static jacking force to install piles into
the ground. Its environmental impact of noise andvibration is smaller than those of conventional piling
methods using drop hammers or vibratory hammers (IPA,
2016). One of the characteristics of the Press-in Methodthat provides an essential difference from the other pile
jacking methods is that a reaction force is secured fromthe previously installed piles. Therefore, the space for(a) Standard press-in(b) Press-in with water jetting(c) Press-in with augering(d) Rotary cutting press-in

piling and the cost for temporary works can besignificantly reduced.
As shown in Fig. 1, there are four press-in pilingtechniques: ‘standard press-in’ that uses no auxiliary
methods, ‘press-in with water jetting’ in which a highpressure water is discharged at the base of a pile, ‘press-in
with augering’ in which an augering device is used toauger the ground before or at the same time with the
installation of a sheet pile, and ‘rotary cutting press-in’ inwhich a vertical and a rotational jacking force are applied
to a tubular pile with teeth on its base at the same time.
Recently, the applicability of the Press-in Method has- 651 -

Fig. 1

Four press-in piling techniques.

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

been significantly expanded, especially in response to the

cutting press-in) and the selection of adequate values fordevelopment of the latter two press-in techniques. Thispress-in conditions such as a rate of penetration or

piling method has been adopted in 37 countries by 2017

extraction, rotation number, a displacement of penetration(IPA, 2017a).

or extraction, and so on. An automatic operation of apress-in machine related with this concept has recently

1.2. Use of press-in piling data
In general, the design and construction of structures

been developed, which is reported in Section 2 in thiswith piles are based on the subsurface information that are

The estimation of subsurface information refers to

obtained by interpolating the results of the site

the estimation of information related with the ground atinvestigations carried out separately from each other withthe base of a pile which is being pressed-in. The

the distance of several dozens of meters or about one

examples of the estimated information are qc and fs ofhundred meters. On the other hand, local variations are

CPT (Cone Penetration Test), soil type and N value ofoften found in the actual ground conditions, such as the

SPT (Standard Penetration Test). It is expected toinhomogeneity of the soil layers and the existence of weak

improve the reliability of the termination control of thesoils or hard cobbles in the ground. The difference

press-in piling work and to provide an objective material

between the prior information and the actual conditions

for judging the necessity of adopting another press-in

related with the ground is one of the major factors thattechnique or modifying the embedment depth of piles.

deteriorate the rationality of the design and construction ofTechnical Committee 2 in IPA finalized a technicalstructures with piles.

material on this issue in 2017 (IPA, 2017b). The third

In the Press-in Method, it is possible to obtain piling

paper.

section of this paper summarizes this issue.

data for each pile. It has been expected that this feature

In the estimation of the performance of piles, it iscan be utilized as a construction technique supported by

expected that a capacity or a stiffness of a pile in a

ICT (Information and Communication Technology) tovertical or a horizontal direction is estimated from theenhance the rationality of the design and construction ofpiling data. This will make it possible to assure thethe structures with piles (Ishihara, 2008). In fact, thequality of each pile while mitigating the impact ofsignificance of this feature had been recognized since

additional time and cost required for confirming thebefore the establishment of Japan Press-in Association in

performance of piles based on the conventional load

1979 (Kitamura, 2018).

testing methods.

The examples of the press-in piling data
are a vertical jacking force, a rotational
jacking force (or torque), a penetration depth,
a time, a rotation number, and so on. Fig. 2
shows the concept of the use of the press-in
piling data. The press-in piling data can beobtained automatically by a system equippedinapress-inmachineatapress-inconstruction site. The obtained piling data aresupposed to be utilized in three ways;
selectingpilingconditions,estimating

subsurface information and estimating theperformance of piles.
The selection of piling conditions refers
to the selection of an adequate press-in
technique (standard press-in, press-in withwater jetting, press-in with augering or rotary

Fig. 2- 652 -

Concept of the use of the press-in piling data.

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

1.3. Objectives of this paper
As a construction technique supported by ICT, thisspecifying the values of the press-in parameters can also

paper introduces two techniques of utilizing the press-in

the press-in piling data, the collection of the piling data atpiling data, which were developed recently and registeredconstruction sites were started extensively in 2007, andwith NETIS (New Technology Information System) inmuch effort has been made by mechanical and electricalJapan in 2017. One is the automatic operation of a press-inengineers in Giken to develop a program for this newmachine and the other is the estimation of subsurface

automatic operation since then. As a result, a system for

information.

this new automatic operation applicable to press-in with

be automated by utilizing the information estimated fromaugering has been put into trial use at several
construction sites since 2013.

2. Automatic operation based on press-in piling data

The comparison of the above-mentioned existing

2.1. Outline of the automatic operation of press-in

automatic operation and the new automatic operation ismachines
When operating a press-in machine, the values ofshown in Fig. 3. In the new automatic operation, press-in

the press-in parameters such as the rate of penetration

piling data such as the penetration depth, the vertical andand extraction, the displacement of penetration androtational jacking force and the inclination of the press-in

extraction, the flowrate of the water jet, the rotation

machine are utilized to estimate the piling state (the state

number of the auger head and so on are controlled so thatof interlocking with the previously installed pile, thethe resistance acting on the pile being pressed-in can beextent of plugging inside a casing of the augering device,

maintained to be sufficiently smaller than the sum of theand so on) and the ground condition at the pile base (SPTreaction forces such as the pull-out resistance of the

N for soils or the unconfined compressive strength forpreviously installed piles, the weight of the press-inrocks). The methods and the results of estimating themachine and so on. There has been existing a techniqueground condition are explained in sections 3.2. and 3.3.

of the automatic operation of the press-in machine, in

Based on the estimated information, adequate values forwhich the values of all the press-in parameters have to be

the press-in parameters are determined and fed back todetermined by the operators themselves. In other words,

the press-in machine. On the other hand, by setting thein this existing automatic operation technique, a press-in

upper limit for some of the press-in parameters or for themachine functions automatically as specified by an

inclination of the press-in machine, it is possible tooperator. Expecting that the process of determining andcontrol the press-in machine to conduct the piling work

Fig. 3

Concept of the use of the press-in piling data.

- 653 -

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

within the possible maximal reaction force. As a result,in press-in with augering (IPA, 2016). One is athe efficiency of the piling work can be improved while

simultaneous augering to install a pile together with an

the accuracy of the piling work are secured.

augering device, which is applicable to the grounds withthe converted SPT N smaller than 75. The other is the

2.2. Case study
A piling work was carried out at a test site in Kochi,

combination of a pre-augering and a simultaneous

Japan, in which both the existing and the new automatic

conducted after the ground is pre-augered by using theoperations were adopted. The site profile is shown in Fig.

same augering device as used in the above-mentioned

4, which is typical for the piling work by press-in withprocess of simultaneous augering.

augering, in which the simultaneous augering isaugering. The ground of the test site is hard with theFig. 5 is the comparison of the modes of theconverted SPT N (Eq. (1)) greater than 75, which means

penetration rate during the pre-augering process, in

that

the

which the penetration rate is higher if the mode of the

pre-augering process is the suitable technique (IPA,

penetration rate is larger. In the existing automatic2016). On the other hand, the ground is highly layered

operation, the mode of the penetration rate wasand contains cobble stones. This requires frequent change

determined as ‘two’ consistently with depth, with whichin the values of the press-in parameters.

the piling can be completed down to the designated depth.

press-inwithaugering

associatedwith

Therefore, the standard mode of the penetration rate wasN  50 

0.3
zSPT ,50

maintained throughout a single pre-augering process. On(1)the other hand, in the new automatic operation, the modeof the penetration rate frequently varied with depth.
Similar trends were found in other press-in parameters as

where δzSPT,50 is the penetration depth of the SPT sampler

well. As a result, as shown in Fig. 6, the duration of ain meters, in response to the blow count of 50 (JGS,

single pre-augering process operated by the new2013).

automatic

In general, there are two different sets of procedures

operationsystemwasreducedautomatic operation system.

Fig. 4byapproximately 30% from that operated by the existingFig. 5 Variation of the mode of the penetration rate.

Site profile in the case study on automatic operation.

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

says that, 1) an adequate construction system should beassured, 2) the embedment of the pile base into thebearing stratum should be confirmed through witnessingor the use of the piling data, and 3) the construction
record should be kept. This example provides a goodreason for expecting the piling data to be utilized in thepreviously-mentioned manner.
Regarding the piling methods for bored piles orusing vibratory hammers, there exist some methods toconfirm the bearing stratum based on the electric current
required for operating an auger or a vibratory hammer(Hashizume et al., 2002; JRA, 2015; JFCC & COPITA,
2017). For driven piles, methods to estimate a static
vertical capacity of a pile based on the piling dataobtained by using an instrumented pile (Likins, 1984;
Rausche et al., 1985) are widely known. On the other
hand, in the Press-in Method, efforts have been made to
Fig. 6

Duration of a single pre-augering process.

develop the estimation techniques in parallel with thedata collection at press-in construction sites in JapanThe trial uses of the new automatic operation havesince 2007, in the same way as the development of the

been carried out at around 15 sites in Japan so far. It has

automatic operation. So far, the estimation techniques

been confirmed that the duration of a single pre-augering

have been developed with regard to standard press-in,

process or a single simultaneous-augering processpress-in with augering and rotary cutting press-in. The

operated by the new automatic operation system isestimation techniques do not require any instrumentation

reduced by from 15 to 40% from that operated by thewith piles.

existing

automatic

operationsystemoroperated

manually by an operator of a standard level, if the site ismulti-layered or contains gravels or cobbles.

3.2. Outline of the estimation methods
In standard press-in, a pile is installed by a static
jacking force without the use of any auxiliary methods. It

3. Estimation of subsurface information from press-in

follows that the process of the penetration of a pile issimilar to that of a cone in CPT. This similarity is taken

piling data

into account in the estimation method in standard

3.1. Outline of the estimation of subsurface
information
As explained in Section 1.2., the technique ofpress-in. The estimation process in standard press-in canestimating subsurface information from the press-in

2015a; IPA, 2017b). Firstly, the vertical jacking force

piling data is expected to improve the reliability of theapplied to a pile by a press-in machine is decomposed

termination control of the press-in piling work and to

into a base resistance (Qb) and a shaft resistance (Qs). Qb

provide an objective material for judging the necessity ofis obtained as the difference between the jacking forces

adopting another press-in technique or modifying themeasured when the pile base passes a certain depth forembedment depth of piles. In Japan, for example, thethe first time and for the second time in each cycle of theissue of an adequate embedment of a pile into a bearing

repeated penetration and extraction (Ogawa et al., 2012;

stratum has recently drawn much attention of citizens,

Ishihara et al., 2015a). Secondly, a unit base resistancedue to an incident of a tilting building in Yokohama City(qb) and a unit shaft resistance (qs) are obtained from Qb

in 2015 (Myall, 2015). In response to this incident, aand Qs, by considering the area on which Qb and Qs are

notice was announced by MLIT (MLIT, 2016), which

acting. For the area of the pile base, the plugging

be divided into four, as shown in Fig. 7 (Ishihara et al.,

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

rotation number (n) as shown in Eq. (2),with A and γ being constants. This is basedon the knowledge that the parameter
Tb/(dc)γ, where dc is the depth of cut (=vd/n), is proportional to the unconfinedcompressive

strength

of

a

rock

(Nishimatsu, 1972; Fukui, 1996; Fujimoto,
2005)

and

the

assumption

that

the

unconfined compressive strength and SPT
N are in proportional relationship. The
second one is the method known as MWD(Measurement While Drilling) (JGS, 2004),
in which SPT N is estimated from Tb, vd, n
and a base resistance on the auger head(Qb) as shown in Eq. (3), with Cn theconstant.

N=A

Tb(vd ⁄n)γN = Cn (Qb + 2π

(2)
Tb
)
v d ⁄n(3)

The estimation process in rotary
cutting press-in is divided into three, as
shown in Fig. 8. Firstly, a vertical and arotational jacking forces applied to a pileby aFig. 7

press-inmachine

(Q,

T)

are

Estimation process in standard press-in.

decomposed into a base and a shaft

conditions are taken into account by introducing IFR,

introducing four equations (Eqs. (4) - (7)) where δsp, Do

Incremental Filling Ratio, to define the effective baseand vr are the frictional angle at the soil-pile interface,area (Ishihara et al., 2018). Thirdly, the obtained qb andthe outside diameter of the pile and the rotational rate ofqs are converted into CPT qc and fs, by considering thethe pile shaft, respectively (Ishihara et al., 2015b).

components (Qb, Qs, Tb and Ts), byscale effect on the plunging values of qb (White & Bolton,2005) and the rate effect based on the Finnie factor(Finnie et al., 1994; White et al., 2010; Bolton et al.,2013). Finally, the soil type and SPT N are estimatedfrom qc and fs, based on the methods developed byRobertson (1990) and Jefferies & Davies (1993)
respectively.

Q = Qb + Qs

(4)

T = Tb + Ts
tanδsp
Tb
=
Do
Qb
3

(5)

Ts
v r ⁄v d
=
Do
Qs
2

(6)
(7)

Regarding press-in with augering, two estimation
methods are proposed, based on the knowledge acquired

Of these, Eq. (6) is based on the assumption that both Qb

in the field of rock drilling (Ishihara et al., 2015a; IPA,

and Tb are expressed by a unit base resistance (qb), while

2017b). The first one is to estimate SPT N from a torqueEq (7) is obtained by assuming that a frictional stress onon the auger head (Tb), a penetration rate (vd) and athe pile is shared by Qs and Ts in the ratio of vd to vr. The- 656 -

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

validity of the latter assumption is discussed in
Bond (2011). Secondly, a value of δE/δV, which isthe energy (δE) required for deforming a soil below
the pile base by a volume of δV, is calculated from
Qb and Tb. δE/δV is an index called Specific Energy,
which is widely used to represent the performanceof machines for rock drilling (Teale, 1965; Hughes,
1972). According to Hughes (1972), Li & Itakura(2012) and others, there is a linear correlation
between the Specific Energy in rock drilling and theunconfined compressive strength of the rock. By

Fig. 8Estimation process in rotary cutting press-in.

extending it, the Specific Energy required forpenetrating something into a ground may be
assumed as being in proportion to the unconfinedcompressive strength of the ground. Therefore,
thirdly and finally, by considering the proportional
relationship between the Specific Energy required
for rotary cutting press-in and that for the
penetration of an SPT sampler, SPT N value isobtained.
3.3. Case studies
Figs. 9 and 10 are the comparison between thesubsurface information obtained by SPT and that
estimated from the piling data in standard press-in(C11-05 and J0617-05), in which a closed-ended
tubular pile with Do = 318.5mm and a sheet pile withthe width of 600mm were pressed-in at vd = 20mm/s

Fig. 9Results of SPT and estimation (C11-05).

Fig. 10

Results of SPT and estimation (J0617-05).

and 30mm/s respectively. The peak values of N andthe soil type are well estimated, while the values ofN other than the peak values are underestimated. The
previous case studies including these two haverevealed that the effect of the plugging condition on
the estimated results is significant while the effect ofthe penetration rate is not (Ishihara et al., 2015a; IPA,
2017).
Fig. 11 is the comparison between thesubsurface information obtained by SPT and that
estimated from the piling data in the pre-augering
process in press-in with augering, using an auger
head with the number of wings of three and theoutside diameter of 450mm. The trend of thevariation of N with depth is well estimated, while
big differences are found at some depths. Throughthe case studies including this, these differences are- 657 -

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

will be better to conduct additional site investigation
not only by means of SPT but also of other methods
such as a trial digging and a large-diameter core tube
sampling(Watanabe

et

al.,

2006).

A

ground-penetrating radar may be another option if itsdifficulty in distinguishing cobbles from cavities(Kimura et al., 2000) is overcome. A surface-wave
method may also be adopted if its resolution is
improved.

Fig. 11

Results of SPT and estimation(pre-augering process in press-in with augering).

believed to be associated with the existence of large
gravels or stones, judging from the records in SPT(Ishihara et al., 2015a; IPA, 2017).
Fig. 12 is the comparison between the subsurface
information obtained by SPT and that estimated from thepiling data in rotary cutting press-in. The trend of thevariation of N with depth is well estimated in this case,(a) Results of SPT.

where the plugging condition were confirmed as almost
constant with depth. Another other case study, on theother hand, has clarified that the effect of the plugging
condition on the estimated results is significant (Ishihara
et al., 2015b; IPA, 2017). If the plugging condition varies
with depth, it is recommended to measure the length of
the soil column inside the pile with a sufficient frequencyof data sampling and obtain the values of IFR
continuously with depth.
It should be borne in mind that the validity of SPT
results is not always assured, especially if the groundcontains gravels and stones. For example, an SPT sampler
sometimes penetrate through the layer containing gravels
and stones without hitting them (Ogawa et al., 2013), as
its outside diameter is as small as around 50mm.
Mitsuhashi (1995) points out that the diameter of gravels(b) Results of estimation.

and stones should be assumed to be at least three times aslarge as what is indicated in the SPT results. Therefore, insome cases, if the subsurface information estimated fromthe piling data significantly differs from the SPT results, it- 658 -

Fig. 12Results of SPT and estimation(rotary cutting press-in).

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

4. Summary
Two techniques of utilizing the press-in piling data,

Behaviour of Offshore Structures, BOSS’94, pp.

which are expected to serve as construction techniques

Hashizume, Y., Uchida, K. and Kiya Y. 2002.

supported by ICT (Information and Communication

Construction management of bored concrete pile.

Technology) to enhance the rationality of the design andProceedings of the 37th Japan National Conference

construction of the structures with piles, were introducedon Geotechnical Engineering, pp. 1391-1392. (inin this paper. One is the automatic operation of theJapanese)press-in machine and the other is the estimation of the217-230.

Hughes, H. M. 1972. Some aspects of rock machining.

subsurface information.

International Journal of Rock Mechanics & Mining

The technique of the automatic operation, developed

Sciences, Vol. 9, pp. 205-211.

for press-in with augering, has been confirmed to be

International Press-in Association (IPA). 2016. Press-in

effective in reducing the duration of the pre-augering

retaining structures: a handbook, First edition 2016.

process by from 15 to 40% in general, especially if the site

International Press-in Association (IPA). 2017a. IPA

is multi-layered or contains gravels or cobbles.

News Letter, Volume 2, Issue 1, p. 1.

The validity of the estimation methods developed forInternational

Press-in

Association(IPA).

2017b.

standard press-in, press-in with augering and rotary

Technical Material on the Use of Piling Data in the

cutting press-in were confirmed through the case studies.

Press-in Method, I. Estimation of Subsurface

In some cases, differences were found between the

Information, 63p.

estimated and the investigated results, and the main

Ishihara, Y. 2008. Study on development of the Pile

reasons for these differences were interpreted as the effect

Penetration

Testsystembasedonpress-inof the plugging condition or the existence of gravels or

construction data, Society for Social Management

cobbles.

Systems, CD-ROM.
Ishihara, Y. Ogawa, N., Okada, K. and Kitamura, A.,
2015a. Estimating subsurface information from data

5. Acknowledgements
The author is grateful to Giken engineers including

in press-in piling. Proceedings of the 5th IPA

Mr. Akio Kitamura, Mr. Hiroaki Tanouchi, Mr. Keigo

International Workshop in Ho Chi Minh, Press-in

Nonaka and Mr. Tatsuo Nose for technical inputs forEngineering 2015, pp. 53-67.

developing the automatic operation. Advice on the

Ishihara, Y. Haigh, S. and Bolton, M. D., 2015b.

estimation of subsurface information provided by the

Estimating base resistance and N value in rotary

members of IPA TC2, chaired by Dr. Osamu Kusakabe,press-in. Soils and Foundations, Vol. 55, No. 4, pp.

is highly appreciated.

788-797.
Ishihara, Y., Kikuchi, Y. and Koseki, J. 2018. Model test

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