2897
Super-long bored pile foundation for super high-rise buildings in China
Fondation profonde sur pieux de très grandes longueurs pour les immeubles de grandes hauteurs
en Chine
Wang W., Wu J.
Department of Underground Structure & Geotechnical Engineering, East China Architectural Design & Research Institute
Co., Ltd. Shanghai, China
Li Y.
Department of Geotechnical Engineering, Tongji University, Shanghai, China
ABSTRACT: In China, super-long bored piles are commonly used as deep foundations to support very heavily loaded super high-rise
buildings. This paper presents some aspects of design and construction of super-long bored pile foundation together with a brief
description of bearing behaviors of super-long bored piles. The issues of selection of pile type and pile tip bearing stratum, load test
pile design, single pile design, pile foundation design, key construction technique and pile quality inspection are discussed with some
engineering practices of super-long pile foundation. These will provide reference and help for futural engineering practice of super-
long pile foundation for super high-rise building.
RÉSUMÉ : Les pieux de très grandes longueurs sont généralement utilisés en Chine pour les fondations profondes afin de supporter
les immeubles de grandes hauteurs. Cet article présente certains aspects du désign et de la construction de ce type de pieux au travers
notamment de leurs caractéristiques de chargement. La méthode de sélection de ces pieux, les tests de chargement, le désign du pieu
lui-même, les aspects clé de la technique et enfin
la méthode d’
inspection sont discutés sur la base de certains cas pratiques. Cette
discussion pourra apporter une référence et une aide pour les prochaines utilisations des pieux de très grandes longueurs.
KEYWORDS: super-long bored pile ; super high-rise building ; field load test ; double steel sleevs ; post grouting technique
1 INTRODUCTION
With the rapid economic growth in the past two decades,
numerous super high-rise buildings have been built in Chinese
riverside and coastal cities and there are more and more super
high-rise buildings under construction or planned to be
constructed. According to statistics, the number of tall buildings
with height of more than 152m will be larger than 1000 in
China during the next 10 years. Moreover, many of them will be
more than 600m in height. Super high-rise buildings, especially
those constructed in soft soil areas, have brought new
challenges to geotechnical engineers. In order to obtain
sufficient bearing capacities, super-long pile foundations are
often adopted for super high-rise buildings. As shown in Table
1, super-long pile foundations were designed for some high-rise
buildings in China by East China Architectural Design and
Research Institute Co., Ltd. (ECADI) (Wang et al, 2011).
Table 1 A survey of pile foundations of some high-rise buildings in China
Building name
Height
(m)
Floors
Pile type
Pile diameter
(mm)
Pile length
(m)
Pile tip bearing stratum
New CCTV Tower
234.0
51
Bored pile
1200
51.7
Sand and gravel
Tianjin Tower
336.9
75
Bored pile
1000
85.0
Silty sand
Tianjin 117 Tower
597.0
117
Bored pile
1000
98.0
Silty sand
Shanghai White Magnolia Plaza
320.0
66
Bored pile
1000
85.0
Medium sand with gravel
Wuhan Tower
438.0
88
Bored pile
1000
65.0
Moderately weathered mud
rock and sand rock
Suzhou International Financial Center
450.0
92
Bored pile
1000
90.0
Fine sand
Wuhan Green Land Tower
636.0
125
Bored pile
1200
60.0
Slightly weathered mud rock
Until now the experience of design and construction of
super-long pile foundation is very limited. Many of the
traditional methods cannot be applied with any confidence since
they require extrapolation well beyond the realms of prior
experience. Therefore, geotechnical engineers are being forced
to summary engineering experience and utilize more
sophisticated methods for design and construction of super-long
pile foundations (Poulos, 2009).
Base on some engineering practices of super-long pile
foundations of super high-rise buildings in China, this paper
presents some aspects of design and construction of super-long
bored pile foundation. Some bearing behaviors of super-long
piles will be reviewed firstly. Then selection of pile type and
pile tip bearing stratum, design of field load test pile and pile
foundation will be discussed. Moreover, some key construction
techniques and pile quality control inspection standards are also
presented. The methods and technical measures of super-long
pile foundation, which are summarized and analyzed in this
paper, can provide some valuable experience, reference and
help for future super high-rise building foundation projects.
2 BEARING BEHAVIORS OF SUPER-LONG BORED
PILE
Super-long bored piles mainly refer to piles with length larger
than 50m and slenderness ratio larger than 50. Both theoretical
research and engineering practice show that the bearing
behaviors of super-long bored piles are different from those of
short and middle long piles. The vertical loads supported by
super-long bored piles are substantial. There are many soil
layers around the pile shaft. The soils characteristics are usually
complex. Construction of super long bored piles is complicated.
It is difficult to control the construction quality. Furthermore,
