地铁车站旁侧基坑分块开挖效应实测分析

FIELD MEASUREMENT ANALYSIS OF BLOCK EXCAVATION EFFECT OF THE SIDE FOUNDATION PIT OF SUBWAY STATION

为探明地铁旁侧基坑施工对车站结构变形的影响,以宁波市已运营地铁车站旁侧某基坑为例,通过对各区块施工期间水平位移变化情况及单区块各工况下的水平位移变化趋势进行分析,得出桩基施工期间,“微挤土”的三轴搅拌桩亦会对车站结构产生较大影响;基坑无垫层、无支撑的时间对车站结构的变形影响极大,且基坑开挖面积越大、与车站平行方向的基坑边长越长影响越明显;基坑与轨道交通结构距离相同的情况下,与车站平行方向的基坑边长越长、开挖面积越大,对轨道交通结构的影响就越大。相关结论可为类似基坑工程提供参考。

A foundation pit at the side of a subway station that has been in operation in Ningbo City was taken to study the influence of subway side foundation pit construction on station structure deformation.The change of hori⁃zontal displacement in each block during construction and the change trend of horizontal displacement in each work⁃ing condition of a single block are analyzed.During the construction of pile foundation,the micro-squeezed triaxial mixing pile has a greater impact on the station structure.The time when the foundation pit is uncushion-free and un⁃supported has a great influence on the deformation of the station structure,and the larger the excavation area of the foundation pit and the longer the side length of the foundation pit parallel to the station with more obvious influence.When the distance between the foundation pit and the rail transit structure is the same,the longer the side length of the foundation pit parallel to the station,and the larger the excavation area,the greater the impact on the rail transit structure.The relevant conclusions in this paper may provide the reference for similar foundation pit projects.