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CLC number: TU47

On-line Access: 2014-06-04

Received: 2014-01-05

Revision Accepted: 2014-04-08

Crosschecked: 2014-05-21

Cited: 1

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Citations:  Bibtex RefMan EndNote GB/T7714

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Journal of Zhejiang University SCIENCE A 2014 Vol.15 No.6 P.419-431

http://doi.org/10.1631/jzus.A1400009


Working characteristics of concrete-cored deep cement mixing piles under embankments*


Author(s):  Chi Wang1, Yong-fu Xu1, Ping Dong2

Affiliation(s):  1. Department of Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; more

Corresponding email(s):   chongdong@sjtu.edu.cn

Key Words:  Concrete-cored deep cement mixing (DCM) pile, Load transfer, Deformation control, Embankment


Chi Wang, Yong-fu Xu, Ping Dong. Working characteristics of concrete-cored deep cement mixing piles under embankments[J]. Journal of Zhejiang University Science A, 2014, 15(6): 419-431.

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author="Chi Wang, Yong-fu Xu, Ping Dong",
journal="Journal of Zhejiang University Science A",
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pages="419-431",
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%T Working characteristics of concrete-cored deep cement mixing piles under embankments
%A Chi Wang
%A Yong-fu Xu
%A Ping Dong
%J Journal of Zhejiang University SCIENCE A
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%P 419-431
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T1 - Working characteristics of concrete-cored deep cement mixing piles under embankments
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A1 - Yong-fu Xu
A1 - Ping Dong
J0 - Journal of Zhejiang University Science A
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SP - 419
EP - 431
%@ 1673-565X
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PB - Zhejiang University Press & Springer
ER -
DOI - 10.1631/jzus.A1400009


Abstract: 
The concrete-cored deep cement mixing (DCM) pile is a new kind of composite pile created by inserting a precast core pile into the DCM column socket and has only been used in a few expressway projects to date. In this paper, full scale field tests of composite foundations reinforced by both concrete-cored DCM piles and by conventional DCM columns under embankments were conducted in northeast of Nanjing Surrounding Expressway (NS-N Expressway), China. With the installation of settlement plates, multipoint settlement gauges, inclinometers, piezometers, pressure transducers, and steel stress meters, the results of plate load tests and long-term monitoring, including ultimate bearing capacity, total settlement, settlement along depth, lateral movement, loading sharing ratio, vertical stress of precast core pile, and excess pore pressure were presented. Based on field test results, the reinforcement effects of composite foundations reinforced by concrete-cored DCM piles and conventional DCM columns were compared. The load transfer characteristics of concrete-cored DCM piles under embankments were also discussed. The test results show that the foundation treatment effect of concrete-cored DCM pile is better than that of the conventional DCM column. Compared to the conventional DCM column, the upper load borne by concrete-cored DCM pile is higher, while the excess pore pressure in concrete-cored DCM pile composite foundation is lower than that in conventional DCM column composite foundation. Under embankment, negative friction occurs at the upper section of concrete-cored DCM pile.

路堤荷载下混凝土芯水泥土搅拌桩工作特性研究

研究目的:研究混凝土芯水泥土搅拌桩在路堤荷载下的荷载传递规律和变形控制机理。
创新要点:评价路堤荷载下混凝土芯水泥土搅拌桩的地基处理效果,测量混凝土芯的竖向应力变化规律和复合地基桩土荷载分担特点,并分析填土过程中混凝土芯水泥土搅拌桩复合地基的固结规律。
研究方法:通过埋设沉降板、分层沉降管、测斜管、土压力盒、孔隙水压力计以及钢筋应力计,在路堤填筑过程中对混凝土芯水泥土搅拌桩复合地基进行了长期现场试验。
重要结论:1.混凝土芯水泥土搅拌桩复合地基的总沉降、工后沉降以及深层水平位移控制效果均较好,优于普通水泥土搅拌桩复合地基;2.混凝土芯水泥土搅拌桩复合地基的桩土应力比以及荷载分担比均大于普通水泥土搅拌桩复合地基,能有效减小土体表面的荷载量,对于控制沉降有一定的效果。3.在路堤这种柔性荷载作用下,混凝土芯水泥土搅拌桩上部会出现一定的负摩擦阻力,存在一个“中性点”。4.混凝土芯水泥土搅拌桩复合地基的固结速率较快,能有效控制由于主固结引起的长期沉降。

关键词:混凝土芯水泥土搅拌桩;荷载传递;变形控制;路堤

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