Proceedings of Indian Geotechnical Conference December 15-17,2011, Kochi (Invited Talk-2.)

GEOTECHNICAL CONSTRUCTION OF PILING FOUNDATIONS ON PROBLEMATICAL

SOIL GROUND OF KAZAKHSTAN

Zhussupbekov, A., Prof. of Geotechnical Institute, ENU of L.N.Gumilyov, Astana, Kazakhstan, astana-geostroi@mail.ru

Lukpanov, R., PhD of Geotechnical Institute, ENU of L.N.Gumilyov, Astana, Kazakhstan, rauan_82@mail.ru

Tulebekova, A., PhD student of Geotechnical Institute, ENU of L.N.Gumilyov, Astana, Kazakhstan, krasavka5@mail.ru

ABSTRACT: Nowadays many megaprojects are building up in new capital of Kazakhstan – Astana. Many foreign leading

companies are take part in construction that results to application of modern and advanced geotechnical technologies, in

particular pile technology. Therefore research of different modern pile technologies (Boring pile, Steel H-pile, CFA-continuous

flight auger, DDS-drilling displacement system) in inhomogeneous soil condition of Astana is presented in this pepper, as well

as technology, advantages and disadvantages. Many field load tests (static, dynamic) were performed, and by results of that

economical and technical efficiency was obtained. Significant differences between experimental (by SLT) and design (by

Standards) bearing capacity of these piles show us incomplete usage of technologies. Research of adjacent soil compaction due

to of high value of concrete pressure during CFA pile installation is also presents, as well as results of compression tests of

surrounding soil after DDS pile installation. Laboratory testing of soil after DDS pile installation allow understanding

relationship between elastic modulus, cohesion, angle of internal friction and DDS pile diameter.Authenticity and reliability of

each pile technology was given by results of more than 30 performed tests. Finally, final element method (FEM) analysis of

CFA and DDS piles was performed to analyze soil work condition around of these piles.

INTRODUCTION

Nowadays pile foundations become most popular during

construction of new capital of Kazakhstan. Very high rates of

construction and appearance of high-rise buildings which

extremely builds up by modern architectural and engineering

megaproject leads to mainly use pile foundations.

Nowadays many megaprojects are building up in Kazakhstan,

especially in new capital – Astana, such as Trade and

entertainment centre Khan Shatyry (See Fig. 1), House estate

- Severnoe Siyanie (See Fig. 2), Palace of Peace - Pyramid

(See Fig. 3) and many other.

Many unique megaprojects are realizing in Kazakhstan

Republic. For example New Aktau city with forecast

population 1.5 million people – the main goal of the project is

creation of the most beautiful city, place of the rest and

tourism not only for Kazakh people, but also for foreigners

(See Fig. 4). Many foreigner specialists from USA, Australia,

UAE and Europe will be attracted to this project. Another

megaproject is construction of the unique housing estate

Abu-Dabi Plaza designed by famous architecture Norman

Foster. This will be a most high building in Central Asia and

14th in the world. Abu-Dabi Plaza - a complex from several

tower, united around the main of the building by height 382

meters - 88 floors (See Fig. 5). Another one example of is

construction of long bridge going through Balkhash lake (See

Fig. 6). The length of the bridge will be 22 km and width is

34 m.

Modern megaprojects put forward modern requirements to

engineers. This led to refuse from traditional out-of-dates

technologies (traditional boring and driving diesel-hammer

piles) and use new more economical and reliable

technologies like CFA (continuous flight auger), DDS

(drilling displacement system), steel “H” piles.

Fig. 1 Trade and entertainment centre Khan Shatyry

Fig. 2 House estate - Severnoe Siyanie

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Askar Zhussupbekov, Lukpanov R & Tulebekova, A

Fig. 3 Palace of Peace - Pyramid

Fig. 4 Megaproject of New Aktau City

Fig. 5 Housing estate Abu-Dabi Plaza

CFA and DDS technology both was established by German

company BAUER. The main distinction of this technology is

that soil compacted under the high value of concrete pressure

during CFA pile installation and due to of soil displacement

without excavation during DDS pile installation.

This both technologies lead to reduction of settlement and

increase of bearing capacities of pile foundation. Steel “H”

piles for the first time are used in construction sites of

Kazakhstan and firstly applied at construction of “USA

Embassy”.

Fig. 6 Megaproject of Balkhash Bridge

Full classification of pile foundation used in constructions

sites of Kazakhstan is presented in Fig. 7.

Fig. 7 Pile foundations on construction sites of Kazakhstan

FETURES OF DDS AND CFA PILE TECHNOLOGIES

Installation of DDS pile consist of four steps, the steps of the

DDS technology are: placing the boring machine to the

boring place; boring the pile hole to the design level; filling

the concrete under the pressure of 300 kPa; installation of

steel anchor into the pile body. See Fig. 8.

Fig. 8 Pile foundations on construction sites of Kazakhstan

Installation of CFA pile consist of following steps: placing

the boring machine to the boring place; boring the pile hole to

the design level; removing the screw with simultaneous

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Geotechnical construction of piling foundations on problematical soil ground of Kazakhstan

concrete filling under the high pressure and replace the

boring machine, installation of steel anchor into the pile body

with preparation of pile head. See Fig. 9.

Fig. 9 Steps of CFA pile installation

In modern CFA technology the systematic employment of

devices auto-recording the drilling data represent a real

breakthrough considering that in the past the CFA method

was not accurate, and relied on the operator’s ability: now

such devices guarantee the control and recording of the data

during the whole construction process. The recorded working

data are usually drilling/withdrawal speed, rotation speed,

depth, concrete pressure and delivery rate per increment of

auger lift during casting.

STATIC LOAD TEST OF DDS AND CFA PILES

Totally it was performed 14 static tests of DDS and 5 CFA

piles of different diameters and length. There are 7 tested

DDS piles of 410 mm diameter and 18 m length, 2 piles of

500 mm diameters and 2.5 m length1nd one pile of 600 mm

diameter and 12 m length. Field static load tests were carried

out for CFA and traditional piles with diameter of 600 mm

and 630 mm and length of 10, 20, 22 24 and 28 m. During DDS SLT loading was done in stages of 400kN and

200kN until 2800kN by three hydraulic jacks type of CMJ-

158A which were contact parallel. , the pressure in the jacks

was created by manual oil pump station MNSR-400, load

was controlled with monometer MTP-160, moving piles was

fixed by caving in-measurers of the type 6-PAO, which were

positioned in the both sides on unmovable bearings of

benchmark system. Reloading was conducted in stages

800kN and 400kN.

Loading of CFA piles was done in stages of 428 kN, 214 kN

and 140 kN by hydraulic jack DG200P150 with carrying

capacity of 2000 kN depending on the value of

settlement and speed of stabilization of deformation. The

pressure in the jack was created by manual oil pump station

NRG-8080, load was controlled with monometer

MA100VU63, Fig. 10.

1 –DDS tested pile; 2 – basic beam; 3 – auxiliary beam; 4– pipes

welded to anchor bar; 5 – jack SMJ-158A; 6 - caving in-measurer 6-

PAO; 7 - benchmark system; 8 – pump NSR-40 and, with

monometer MTP-160.

Fig. 10 Testing of CFA pile by static load

The first count out – right after putting the loading, then

consequently 4 counts out with the interval 15 minutes, 2

counts out with the interval 30 minutes and further in

every hour till the conditional stabilization of deformation.

For the criterion of conditional stabilization of deformation

was taken the speed of settlement of boring piles on the

given stage of loading that did not exceed 0.1mm during the

last 1 hour of observation.

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Askar Zhussupbekov, Lukpanov R & Tulebekova, A

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FEM Result of 20m CFA pile

CFA 5 (20m)

According to requirements of Kazakhstan Standard - SNiP

RK 5.01-03-2002 – ultimate value of settlement of the tested

pile is determined by Eq. 1:

mtuSS , (1)

where = coefficient for conversion factor of the limit value

of mean settlement of foundation of the building or structure

Su,mt into pile settlement obtained while static tests at

conventional settlement stabilization; mtSu, = is maximum

permissible value of foundation settlement of the designed

building or structure as stated either in the project statement

or Kazakhstan Standards requirements.

COMPARISON CFA AND CASING BORING

(TRADITIONAL) PILES

The comparison of CFA and traditional boring piles was

performed on construction sites: “Trade and entertainment

centre Khan Shatyry” and house estate of “Severnoe

Siyanie”. Field static load tests were carried out for CFA and

traditional piles with diameter of 600 mm and 630 mm.

A CFA pile is a type of drilled foundation in which the pile is

drilled to the final depth in one continuous process using a

continuous flight auger. The use of the continuous flight

auger rig avoids many of the problems of drilling and

concreting piles experienced when using conventional power

augers. The new CFA equipment can perform piles in most

type of soils (including sand, gravel, silt, clay, chalk and

weak weathered rock) with diameters up to 1200 mm and

lengths down to 35-40 meters. So, with proper planning and

design, performing equipment and skilled personnel, high

production rates and high quality product can be achieved

[Klosinski & Rychlewski].

In modern CFA technology the systematic employment of

devices auto-recording the drilling data represent a real

breakthrough considering that in the past the CFA method

was not accurate, and relied on the operator’s ability: now

such devices guarantee the control and recording of the data

during the whole construction process. The recorded working

data are usually drilling/withdrawal speed, rotation speed,

depth, concrete pressure and delivery rate per increment of

auger lift during casting. The numerical analyses are

important for understanding the interaction of CFA pile with

soil ground. The elasto-plastic analysis was provided by

FEM. It was used the mechanical properties of soil ground

for the numerical calculation of bearing capacity and

settlement. For analyzing bearing capacity of working as

friction CFA and Casing piles were modeled by numerical

computer program of FEM and compared with results of field

static load test. FEM mesh for calculation of single bored pile

is illustrated in Fig. 11.

Taking advantage of the axi-symmetric nature of the

problem, only a half domain of the model ground and pile

were analysed. The soil ground and pile were descretized into

four noded quadrilateral elements. Number of nodal points

are 675, number of finite elements are 606, number of

materials are 4 (1is sand with gravel, 2 is hard clay, 3 is clay,

4 is bored pile).

The results show that experimental and theoretical results are

not so different and presents in Figs 12-13.

Fig. 11 Mesh for finite element method

Fig. 12 Comparison “load-settlement” curves of field static

load test of piles and FEM, (Khan Shatyry)

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Geotechnical construction of piling foundations on problematical soil ground of Kazakhstan

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FEM Results

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Fig. 13 Comparison “load-settlement” curves of field static

load test of piles and FEM, (Severnoe Siyanie)

Through technology of CFA in construction sites “Grand

Astana” “Severnoe syanie” and “Khan Shatyry” before us

there was a question over-expenditure of concrete at the

installation of CFA pile. The actual volume of borehole was

about 1.3-1.4 times more than theoretical volume of borehole

[Zhusupbekov & Ashkey e.g.] After determination of

preliminary average radius (r+ r) increasing diameter of

CFA piles and remodeled numerical mesh of “Severnoe

Siyanie” and “Khan Shatyry” for FEM. It gives us increasing

bearing capacity of CFA piles respectively “load-settlement”

results of field static load test and stress and strain of soil

around of single CFA pile through FEM computer program.

The results of “load-settlement” through FEM illustrated in

Figs. 14-15.

Fig. 14 Comparison static load test and FEM results after

increasing of diameter of CFA pile, (Khan Shatyry)

Fig. 15 Comparison static load test and FEM results after

increasing of diameter of CFA pile, (Severnoe Siyanie)

COMPARISON DDS (FDP) AND CASING BORING

(TRADITIONAL) PILES

The principal feature of DDS technology is special boring

element, presented in Fig. 16. The pile hole forming via two

stages: during the moving of boring element down the bullet

teeth loose the soil and stabilizer displaces surrounding soil.

During the moving of boring element up the secondary

compaction of hole has a place.

Fig. 16 Cone-shape tool for a boring and displacement of

soils

In order to research DDS pile the static load tests (SLT) of

DDS and Casing boring piles were performed. The main

purpose of SLT performance is comparison of bearing

capacity of DDS and Casing pile. Totally it was performed 14

static tests of DDS piles of different diameters and length on

two construction sites [Sultanov & Zhussupbekov e.g.]

First construction site is “Trade and entertainment centre

Khan Shatyry”. Totally 11 piles were tested on this site, there

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Askar Zhussupbekov, Lukpanov R & Tulebekova, A

are 8 tested piles of 410 mm diameter and 18 m length, 2

piles of 500 mm diameters and 10 m length, and one pile of

600 mm diameter and 18 m length. Construction sites No 2 is

“Industrial Base” where were tested 3 DDS piles 500 mm of

diameter and 2.5 m length.

Comparison of DDS and Casing boring piles bearing

capacities are presented in Fig. 17. As you see there is big

difference between DDS and Casing boring piles bearing

capacities.

Fig. 17 Comparison of DDS and Casing boring piles bearing

capacities

Significant differences between bearing capacities of DDS

and Casing boring piles show us incomplete usage of DDS

technology resources. Classically differ two stages of pile

works under the vertical load: during the first stage is

developing the ultimate state of stress-stain condition of soil,

during the second stage the slippage of pile through the soil

has a place. DDS pile works identically, but in case of DDS

pile surrounding soil subject to compaction, this lead to

increase of bearing capacity. As you know classically bearing

capacity subdivides into two constituent there are: shaft and

tip resistance. In Kazakhstan`s standard - Soil basement and

foundations classical equation was modified, and presented

by following equation:

(2)

where yc = safety factor; ycR and ycf = coefficients of soil work

condition under the pile tip and surround of pile respectively.

In this case we interested by coefficient of soil work

condition. In case of traditional bored pile no compaction is

occurred therefore coefficient of shaft work of pile equal 0,7,

in case of DDS piles due to of surrounding compaction of soil

this coefficient must be increased. Moreover in case of DDS

pile surrounding soil only undergoes to compaction, under

the pile no compaction. By results of static load tests of DDS

and Case piles the inverse problem was performed to

definition of interested us coefficients. Obtained coefficients

of DDS piles shaft work for different EGE (engineering

geological elements) were presented in Table 1.

Table 1 Coefficients of DDS piles shaft work

Depth, m Ycf Ycf(average)

EGE2

5 1,23 6 1,18 7 1,15 5 1,45 6 1,37 7 1,32 5 1,67 6 1,56 7 1,23

1,38

EGE3

5 1,31 6 1,25 7 1,21 5 1,33 6 1,26 7 1,21 5 1,32 6 1,25 7 1,21

1,26

EGE4

5 1,12 6 1,08 7 1,05 5 1,21 6 1,16 7 1,12 5 1,43 6 1,34 7 1,28

1,20

After reprocessing of obtained data by statistic analysis

several results of elastic modulus were rejected from

following analysis. It is necessary take account elastic

modulus, angle of internal friction and cohesion increase due

to compaction during design DDS pile. With that view the

nomograms were developed, Fig. 18-20. By these

nomograms designers may easily correct elastic modulus,

angle of internal friction and cohesion of different

engineering element of Astana, to accurate design DDS piles.

Fig. 18 Elastic modulus correction nomogram

iicfcRcd hfuRAF

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Geotechnical construction of piling foundations on problematical soil ground of Kazakhstan

Fig. 19 Cohesion correction nomogram

Fig. 20 Internal friction angle correction nomogram

DRIVING STEEL “H” SECTION PILES

Driving steel “H” piles were installed on “USA Embassy”

construction site. The site is situated on the Southeast side of

Astana city on the right side of the Esil river, and so ground

soil presented by soft loam and clay soil with a rare lenses of

gravel sand. Steel piles “H” section of type HP12x74

(HP305x110) was made from high-strength low alloy

colombia-vanadium of class 50 (345) according to ASTM

A572. The maintenance of chemical elements in structure of

steel of pile are: carbon (C) – min 0.08%; Iron (Fe) – 98%;

Manganese (Mn) – 1.35%; Fluorine (P) – max 0.04%;

Sulphur (S) – max 0.04%; Silicon (Si) – max 0.04% [Bazilov

R.K]. On an edge of pile shoe from the strong steel tips HP-

7780-B made Associated Pile and Fitting Corp (Clifton, satae

of New Jersey) weld.

First static load test was performed for 7 m length of pile.

The bearing capacity of this pile had been 500 kN. It was

chosen to increase the bearing capacity to designed level by

jointing pile sections. The length of pile was increased step

by step and SLTs were repeated to attain allowable value of

bearing capacity. Finally designed bearing capacity was

achieved for 10 m length of steel pile. Results of static load

tests for different length of steel piles presented in Fig. 21.

The advantages steel piles is possibility of joint the sections

to increase of pile length, therefore depth of steel pile is

unconfined. Steel piles has one significant disadvantage is

impossibility to use in aggressive soil condition even in

unaggressive soil condition steel piles is very expansive due

to of anticorrosive actions.

Fig. 21 Increscent bearing capacity by results of extension of

pile length

COMPARISON SLT RESULTS OF DIFFERENT

TYPES OF PILE

SLT of different types of pile was performed with a view to

compare bearing capacity of traditional (namely, boring

casing pile and driving pile).

Unfortunately, most part of tested piles is not achieved

ultimate settlements prescribed by Kazakhstan Standard -

24mm, and so, for bearing capacity comparison it was

chosen to use 3mm settlement criteria, as long as all the

piles achieved this settlement.

All the piles were designed to the criteria of 2200kN bearing

capacity. Designed parameters of piles (length and cross

section) by Kazakhstan Standards are presented in Table 2. Table 2 Designed pile characteristic

Type of

pile

Required

quantity, e.a.

Length of

pile, m

Diameter or

cross section,

m

CFA 1 10 0.5

DDS 1 10 0.5

Casing 1 10 0.5

Driving 2 12 0.3 x 0.3

Results of comparison are presenting in Fig. 22

and Table 3.

All of these coefficients show incapacity of accurate design

of modern pile technology by out-of date Standards,

otherwise this coefficients tending to 1. The results of SLT

showed entirely expected regularity. CFA piles showed

highest bearing capacity as long as during CFA pile

installation it was expended much more concrete (in 2 times)

than during Casing pile installation. This factor was not

considered during design, the coefficient therefore equal

1.43. DDS pile approved effluence of compacted soil and

coefficient therefore equal 1.22 (DDS versus Casing).

Differences between Driving and Casing pile neglected

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Askar Zhussupbekov, Lukpanov R & Tulebekova, A

small, the reason of differences might be empirical

coefficients required by Standards.

Table 3 Comparison of different piles

Description Coefficient of reserve

FCFA/FDDS 1.17

FCFA/FCasing 1.43

FCFA/FDriving 1.55

FDDS/FCasing 1.22

FDDS/FDriving 1.33

FCasing/FDriving 1.08

Fig. 22 Comparison of different piles

CONCLUSIONS

The results of field static load tests of CFA piles showed high

value bearing capacity higher than traditional casing pile.

For designing CFA technology for pile foundations of

buildings and structures need consider volume changing

of borehole by appearance in borehole additional pressure

respectively over-expenditure of the concrete depending

soil conditions and length of piles. CFA pile more

productivity than traditional casing pile. It is possible to

install 6 CFA piles per working day versus 3 casing

piles.

Significant differences between bearing capacities of DDS

and Casing boring piles show us incomplete usage of DDS

technology resources. Kazakhstan standards have not any

recommendations to DDS pile design, prescribed in standards

recommendation applicable for traditional pile design and

give not accurate results for DDS pile design. The coefficient

of shaft work of DDS pile was defined and equal from 1.2 to

1.38 depending on soil condition. Application of DDS

technology allows reducing total expanse per 35 to 40%.

The reason of big difference between DDS experimental and

designed bearing capacity is strengthening of surround soil

due to of technological compaction. This lead to increase of

soil parameters such as angle of internal friction, cohesion,

Young modulus and so on. By the results of laboratory

testing the nomograms to correct angle of internal friction,

cohesion, and Young modulus were developed. It is possible

to use these nomograms during design DDS pile of 400, 500

and 600mm of diameter in similar soil condition.

Steel “H” piles for the first time are used in construction sites

of Kazakhstan and firstly applied at construction of “USA

Embassy”. Application of steel piles more expansive then

prefabricated concrete driving piles due to of expansive

anticorrosive actions. Nevertheless it is possible to increase

bearing capacity of steel pile by expansion pile length by

jointing the steel sections.

REFRENCES

1. B. Klosinski & P.Rychlewski. Analysis of bearing

capacity and settlement of CFA piles. Deep

foundations on bored and auger piles, Van Impe (ed.),

Rotterdam, 2003. – pp. 153-156.

2. A. Zh. Zhusupbekov and Y. Ashkey, V.N. Popov, A.J.

Belovitch and G.A. Sultanov, Analyzing the static test of

boring piles through CFA technology. Proceedings 4th

International Conference on Soft Soil Engineering, 2006,

(Canada, Vancouver), 213-215 .

3. Ashkey, E. (2008). “Interaction of CFA bored piles with

soil condition in Astana.” A dissertation submitted for the Ph.D. degree. Astana, Kazakhstan. 50-52.

4. G.A. Sultanov, R.E. Lukpanov, S.B. Enkebaev. Research

of Interaction between Displacement Pile and Soil

Basement. Proceedings of Kazakhstan-Korean joint

geotechnical seminar. 2010, Astana, Kazakhstan, 84-91

pp.

5. Sultanov, G., Zhusupbekov, A., Lukpanov, R, Enkebaev,

S., (2010). Laboratory testing of elastic modulus of soil

around of displacement pile. Proc. L.N.Gumilyev

Eurasian National University. Astana, Kazakhstan, 214-

219.

6. Sultanov, G., Zhusupbekov, A., Lukpanov, R, Enkebaev,

S., (2010). Definition of dependence between

experimental and designed values of bearing capacities of

displacement pile. .” Proc. L.N.Gumilyev Eurasian

National University. Astana, Kazakhstan, 226-232.

7. Sultanov, G., Zhusupbekov, A., Lukpanov, R, Enkebaev,

S., (2010). Comparison analysis of DDS and traditional

boring pile works by FEM analysis results. Proc.

L.N.Gumilyev Eurasian National University. Astana,

Kazakhstan, 219-226.

8. R.K. Bazilov. Research of steel “H” section piles in soil condition of Astana. A dissertation submitted in partial

fulfillment of the requirements for the degree of doctor of

philosophy, 2008, 58-63 pp.

9. SNiP RK 5.01-03-2002 “Pile foundation”. 10. SNiP RK 5.01-01-2002 “Soil basement and foundations”.

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