基于MIDAS GTS NX对深基坑开挖变形的规律研究

The Law of Excavation Deformation of Deep Foundation Pit based on MIDAS GTS NX

以合肥市某地铁深基坑工程项目为背景,选用MIDAS GTS NX有限元分析软件建立三维基坑模型,对基坑开挖过程中围护结构的水平位移、基坑坑底隆起以及基坑地表沉降的变形情况进行数值模拟分析。结果表明:随着基坑开挖深度的增加,围护结构邻近建筑物的一侧变形会更明显,最大位移位于围护结构埋深的0.45~0.55倍处;靠近基坑中部的隆起量要大于基坑边缘,变化趋势呈开口向下的抛物线形,最大隆起量为17.29 mm;地表沉降变化趋势类似为“凹槽形”,最大值为12.25 mm,离基坑边缘中点的位置为0.58倍基坑开挖深度。同时将现场监测值与模拟数值对比分析,两者变形规律相似且误差较小。

Taking a deep foundation pit project of a metro in Hefei as the background and the MIDAS GTS NX finite element analysis software selected to establish a three-dimensional foundation pit model,the horizontal displacement of the envelope structure,the uplift of the foundation pit bottom and the surface deformation of the foundation pit during the excavation of the foundation pit were numerically analyzed.The results showed that with the increase of excavation depth of the foundation pit,the deformation of one side of the adjacent building of the enclosure structure was more obvious,and the maximum displacement was located at 0.45~0.55 times the buried depth of the enclosure structure;the uplift near the middle of the foundation pit was greater than that of the edge of the foundation pit,and the changing trend was parabolic with the opening downward,and the maximum uplift was 17.29 mm;the surface settlement change trend was similar to“groove”with the maximum value of 12.25 mm,and the position from the midpoint of the edge of the foundation pit was 0.58 times the excavation depth of the foundation pit.At the same time,the on-site monitoring value and the analog value were compared and analyzed,and the deformation law of the two was similar,with the small error.