以某实际相邻双基坑工程为原型,利用PLAXIS建立相邻基坑开挖的二维模型,采用HS土体本构模型,分析相邻基坑同步开挖对土体位移、支护结构变形与内力的影响;考虑不同开挖工序和不同基坑间距,分析相邻基坑开挖的影响范围和基坑支护结构在不同开挖工序下的变形特征.对相邻基坑同步开挖下的支护结构位移进行了实测.结果表明,邻近基坑开挖卸荷对基坑间土体沉降、坑底隆起、坑外地表沉降、支护结构内力与变形等产生明显影响.相邻基坑间距、开挖顺序和支护方式是其主要影响因素.
A two-dimensional finite element model for the actual twin adjacent foundation pits was established by PLAXIS software,in which the Hardening Soil model was used as the soil constitutive model. The impacts of synchronous excavation on the displacement of surrounding soils,internal forces and deformations of supporting structures of the adjacent foundation pits were discussed. Also,the range of influenced surrounding soils of adjacent excavations and the deformation features of supporting structures were investigated by considering excavation sequence and different distance between adjacent excavations. Further,the deformations of supporting structures under synchronous excavation were measured. The results indicate that the uploading due to ajacent excavation exerts significant impacts on soil settlement between the twin adjacent excavations,basal-heave,surface settlement outside the excavations,internal force and deformation of supporting structures. The distance between adjacent excavations,excavation sequence and supporting pattern are the main influencing factors.