合肥地区地铁车站深基坑稳定性分析

Stability analysis of deep foundation pit of subway station in Hefei City

文章以临近某国家级实验室的地铁车站深基坑为研究背景,针对合肥地区上层为黏性土、下层为泥质砂岩的地质状况,研究了地铁车站深基坑施工对周边建筑物的影响,确保基坑和支护结构安全施工。采用有限元分析软件MIDAS/GTS建立了弹塑性有限元模型,针对不同的围护设计形式对基坑变形进行敏感性分析,并对车站深基坑开挖的施工过程进行仿真模拟计算,预测深基坑开挖将产生的基坑变形及对该实验室的影响。研究结果表明:钢支撑施作位置的不同对基坑的侧向位移有一定的影响;对于不同的围护桩入土深度,土体向基坑内侧变形的趋势基本相同,随着入土深度的增大,基坑的侧向变形有所减缓;围护桩+钢支撑的围护形式对基坑土体侧向位移及周边地表沉降有较强的限制作用。研究成果对该地铁基坑的安全施工具有重要的现实指导意义。

Taking the subway station deep foundation pit project near a national laboratory as research background,and considering the geological condition in Hefei City that the upper layer is clay and the lower layer is argillaceous sandstone,the influence of the construction of this deep foundation pit on surrounding buildings is studied to ensure the safety of the excavation.Elastoplastic finite element model is established using finite element software MIDAS/GTS,and sensitivity factors analyses of the foundation pit deformation are conducted with different forms of retaining design.The simulation calculation of the foundation pit construction is made to predict the deformation of the foundation pit and its effect on the laboratory.The results show that the position of steel support plays an important role in the lateral deformation of the foundation pit.The tendency of the soil displacement to the inside of the foundation pit is the same with the different depth of retaining piles into soil.Furthermore,as the increase of the depth of retaining piles into soil,the lateral displacement of the foundation pit becomes small.The retaining form with steel support and retaining piles has good limit to the settlement of surrounding ground and the lateral deformation of the foundation pit soil.The research results are of practical significance for the construction safety of the foundation pit of the subway station.