软土区狭长基坑群对下卧地铁车站变形影响分析

ANALYSIS OF THE INFLUENCE OF LONG AND NARROW FOUNDATION PITS IN SOFT SOIL AREA ON THE DEFORMATION OF UNDERGROUND SUBWAY STATION

为探究管道基坑群的开挖对临近地铁结构安全影响,以天津某临近地铁管道基坑群为研究载体,采用MidasGTS-NX数值分析软件为研究工具,研究了狭长型基坑,地铁与基坑距离以及基坑开挖顺序对临近地铁变形影响。结果表明狭长型管道基坑群开挖对周边建筑物的影响受狭长型基坑“长边效应”,基坑与地铁车站结构距离和管道基坑开挖顺序综合影响。距离地铁车站结构最近点处管道基坑开挖卸载致使地铁车站结构变形陡增,变形量约占总变形量的50%~90%,研究结果为临近地铁结构的基坑群设计及施工提供理论依据。

The excavation of pipeline foundation pit group often affects the safety of adjacent subway structures.A foundation pit group near a subway pipeline in Tianjin is taken to study the influence of the narrow and long founda⁃tion pit,the distance between the subway and the foundation pit,and the excavation sequence of the foundation pit on the deformation of the adjacent subway by using the MidasGTS-NX numerical analysis software.The results show that the influence of the excavation of the narrow and long pipeline foundation pit group on the surrounding build⁃ings is affected by the long side effect of the narrow and long foundation pit,the structural distance between the foun⁃dation pit and the subway station,and the excavation sequence of the pipeline foundation pit.The excavation and un⁃loading of the pipeline foundation pit at the nearest spot to the subway station structure cause the structural deforma⁃tion of the subway station to increase,accounting for about 50%~90%of the total deformation.