摘要
通过在上海S32高速公路某桥头处理段开展长短桩组合型复合地基现场试验,研究路堤填筑过程以及堆载预压期内桩土应力比、分层沉降、桩顶面和桩间土表面沉降、孔压等工程性状的变化规律;采用三维有限元法进行拓展研究,对比分析长短桩组合型复合地基与等长桩复合地基的加固机理。研究结果表明:随着路堤填土高度的增加,长桩和短桩的桩土应力比均逐渐增大并趋于稳定,稳定时长桩和短桩的桩土应力比分别为7～10和3～5;桩顶面和桩间土表面的沉降主要发生在填土期,预压期内沉降趋于稳定;总桩长相同的条件下,长短桩组合型复合地基加固效果优于等长桩复合地基,且存在持力层时的层状地基更利于长短桩组合型复合地基性能的发挥。
Field tests of non-uniform pile-supported foundation were carried out at a bridgehead of Shanghai S32 expressway on the purpose of exploring the pile-soil stress concentration ratio, layered settlements, settlement of pile cap and foundation soil surface, and the pore pressure, which were changing with the embankment filling. Based on the fundamental parameters with the field test, the three-dimensional numerical model was built to carry out the comparison with the field test results and expand the research on the difference between the new ground improvement and the traditional composite foundation with uniform piles. The results show that both the stress concentration ratios of the long piles and the short ones increase with the embankment filling and tend to be stable when the stress concentration ratios of long piles are 7-10 and 3-5 for short piles. The settlements of the pile top surface and the ground soil surface come into beingmainly embank stratum during the embankment filling. The non-uniform piled foundation is better in reducing ment settlement than the traditional ground improvement especially when the bearing exists.
出处
《中国公路学报》
EI
CAS
CSCD
北大核心
2013年第1期9-14,共6页
China Journal of Highway and Transport
基金
国家高技术研究发展计划("八六三"计划)项目(2007AA11Z117)
关键词
道路工程
长短桩
现场试验
桩土应力比
沉降
复合地基
road engineering
long and short piles
field test
stress concentration ratio
settlement
composite foundation
