黄土挖填场地桩筏基础承载特性的数值模拟研究  

Study on Numerical Simulation of Bearing Properties of Piled Raft Foundation in Loess Cut-fill Site

作　　者：原兴霞 程辉[1] 门玉明[1] 高洁[2] 李凯玲[1] 

机构地区：[1]长安大学地质工程与测绘学院,陕西西安710054 [2]信息产业部电子综合勘察研究院,陕西西安715500

出　　处：《安全与环境工程》2017年第4期154-161,共8页Safety and Environmental Engineering

基　　金：陕西省科技统筹创新工程计划项目(2012KTZD03-07);中央高校教育教学改革专项项目(研究生卓越人才培养计划项目;jgy16035);中央高校基本科研高新技术研究培育项目(310826172203)

摘　　要：为充实黄土地区挖填结合场地桩筏基础物理模型试验的相关结论,应用FLAC3D数值分析工具对分级荷载作用下跨越黄土挖填结合区的桩筏基础进行了深入分析,研究了黄土地区挖填结合场地桩筏基础的受力特点和变形特征,并综合部分模型试验结果,验证了数值分析结果的可靠性。结果表明:黄土地区挖填结合场地的桩筏基础桩基承载性状均为端承摩擦桩,且挖方区和挖填结合区灌注桩的承载性能优于填方区灌注桩;黄土挖填结合区由于土层工程性质差异以及填土厚度不均,在荷载作用下极易产生差异沉降,造成筏板下地基土出现"葫芦瓢"形的沉降特征,引起筏板的挠曲变形,不仅使筏板自身产生较大的弯矩,也对下部桩基的弯矩产生重要影响。该研究成果可为黄土地区挖填结合场地的桩筏基础设计提供参考。In order to enrich the conclusions of the physical model experiments of piled raft foundation,this paper analyzes the grading loads of piled raft foundation across cut fill site by using FLAC3D numerical analysis tool.The paper studies the stress characteristics and deformation characteristics of piled raft foundation in the cut fill site.Considering partial results of modelexperiments,the paper verifies the reliability of the numerical analysis results.Results show that the piled raft foundation in cut fill site are all end bearing frictional piles,and the load carrying properties of piles in the cutting site or cut fill site are better than those in the filling site. There are differential settlements in cut fill site under the load due to the different soil engineering properties and uneven thickness of filling soil,which may bring about settling characteristic similar to ＂half gourd＂ type the under the raft foundation and the flexural deformation of raft.It not only makes the raft itself produce large bending moment,but also produces important impact on the bending moment of the piles.We expect this study could provide reference for the design of pile raft foundation in Loess cut fill site.

关 键 词：黄土地区 挖填结合区 桩筏基础 内力 变形 FLAC3D 

分 类 号：TU473.1[建筑科学—结构工程]