基坑开挖对既有复合地基单桩的位移性状影响分析  

Analysis of horizontal displacement of single-pile of existing composite foundation subjected to pit-excavation

作　　者：李连祥[1,2] 陈天宇 白璐 季相凯[1,2] 黄亨利 LI Lianxiang;CHEN Tianyu;BAI Lu;JI Xiangkai;HUANG Hengli(School of Civil and Hydraulic Engineering,Shandong University,Jinan 250061,China;Foundation Pit and Deep Foundation Engineering Research Center,Shandong University,Jinan 250061,China)

机构地区：[1]山东大学土建与水利学院,山东济南250061 [2]山东大学基坑与深基础工程技术研究中心,山东济南250061

出　　处：《西安建筑科技大学学报（自然科学版）》2019年第4期486-492,共7页Journal of Xi'an University of Architecture & Technology(Natural Science Edition)

基　　金：济南市科技计划(201201145)

摘　　要：在无载复合地基侧向开挖离心机试验基础上建立了数值模拟模型,基于Winkler地基模型,根据桩土的位移变形协调方程,采用两阶段法求解复合地基单桩的水平位移,并与数值模拟结果进行对比。在数值模拟基础上,改变复合地基的置换率,得到了不同置换率以及不同开挖深度下的单桩的水平位移,模拟并对比了在复合地基至支护结构不同距离情况下的土体最大水平位移,研究结果表明:①将复合地基视为均质土体,通过二阶段法求解复合地基单桩位移的方法可行;②当复合地基桩间距大于4倍单桩桩径时,复合地基对于单桩的水平位移影响较小。在设计支护结构时,当基坑深度小于5m时,可以忽略复合地基与土体间的相互影响,深度大于5m时,应充分考虑复合地基的影响;③当复合地基距离支护结构的距离在基坑开挖深度的0.8倍以内时,其对土体的侧向加固作用才有较好效果。Based on the lateral excavation of unloaded composite foundation centrifuge test,a numerical simulation model is established.Based on Winkler foundation model,the two-stage method is used to calculate the horizontal displacement of single pile based on the displacement-deformation coordination equation of pile-soil,and compared with the numerical simulation results.Based on numerical simulation,by changing the displacement of composite foundation,different displacements and horizontal displacements of single pile under different excavation depths were obtained.The horizontal displacement is calculated under different distances from composite foundation to the retaining wall.The results can be concluded as follows:①The applicability of regarding composite foundation as a homogeneous soil to solve the horizontal displacement of Single Pile is proved.②When the distance between piles is greater than 4 times of single pile diameter,the horizontal displacement of composite foundation has little effect on the horizontal displacement of pile;when the depth of the foundation pit is less than 5m,the interaction between the composite foundation and the soil can be neglected;and when the depth is more than 5m,the influence of the composite foundation should be taken into full consideration.③When the distance of the composite foundation from the supporting structure is within 0.8 times of the excavation depth of the foundation pit,it has a better effect on the lateral reinforcement of the soil.

关 键 词：复合地基 单桩水平位移 二阶段法 WINKLER模型 置换率 

分 类 号：TU441[建筑科学—岩土工程]