复杂地层下桩锚支护基坑变形特性研究

Study on Deformation Characteristics of Pile-anchor Supporting Foundation Pit Under Complex Stratum

随着基坑工程的快速发展,地层分布情况变得愈发复杂。为了研究复杂地层下桩锚支护基坑的变形特性,本文以成都某建筑基坑工程为研究对象,采用有限元计算的手段,对桩锚支护结构下基坑的变形特性展开分析,研究基坑开挖下围护桩变形受力、周边地表沉降、坑底隆起变形以及周边土体水平位移的变化规律。研究表明:围护桩的水平位移呈现减小趋势并在桩顶处位移最大,弯矩呈先增后减趋势;而地表沉降以“V”字形状分布,并在距离基坑侧壁4m处地表沉降最大,后逐渐减小至0;基坑底部底板隆起范围约为底板以下20 m深度内的土体,整体变化较小。研究结果可为复杂地层下基坑支护结构设计提供一定的参考。

With the rapid development of foundation pit engineering,stratum distribution becomes more and more complicated.In order to study the deformation characteristics of pile-anchor support foundation pit under complex strata,this paper takes a building foundation pit project in Chengdu as the research object,adopts the finite element method to analyze the deformation characteristics of the foundation pit under pile-anchor support structure,and studies the changes of the deformation force of the retaining pile,the surrounding surface settlement,the uplift deformation of the bottom of the pit and the horizontal displacement of the surrounding soil.The results show that the horizontal displacement of the pile decreases and reaches the maximum at the top of the pile,while the bending moment increases first and then decreases.The surface settlement is distributed in the shape of"V",and the maximum surface settlement is 4m away from the side wall of the foundation pit,and then gradually decreases to 0.The uplifting range of the bottom floor of the foundation pit is about 20 m below the bottom floor,and the overall change is small.The research results can provide some reference for the design of foundation pit support structure under complex stratum.