地铁深基坑开挖引起临近的扩大基础建筑物变形模拟及保护措施研究

Study on Deformation Simulation and Protection Measures of Adjacent Enlarged Building Caused by Excavation of Deep Foundation Pit in Subway

深圳某地铁项目地铁站点位于较繁华地段,场地周围环境复杂,工程地质条件较差。某建筑采用扩大基础,占地面积9700 m^2,地上结构5层,距离基坑边20 m。采用有限元软件分别模拟了基坑开挖过程中建筑(加固前和加固后)2种工况下的变形情况。分析发现,基坑开挖的卸荷造成周围土体应力重分布,发生变形,使建筑物基础产生不均匀沉降,当沉降值超过建筑结构的极限承载力后,建筑会发生破坏。基坑开挖对建筑物的影响随着建筑与基坑距离的增大而减小;对建筑物基础和基坑底部进行加固,可有效地控制建筑物和基坑的变形。

The subway station of a subway project in Shenzhen is located in a more prosperous area,the surrounding environment is complex,and the engineering geological conditions are poor.A building adopts an enlarged foundation,covering an area of 9700 m^2,with 5 floors above ground and 20 m from the side of the foundation pit.In this paper,the finite element software is used to simulate the deformation of foundation pit excavation on the construction(before and after reinforcement).The analysis found that the unloading of the foundation pit caused the stress distribution and deformation of the surrounding soil,which caused uneven settlement of the building foundation.When the settlement value exceeded the ultimate bearing capacity of the building structure,the building would be damaged.The influence of foundation pit excavation on the building decreases with the increase of the distance between the building and the foundation pit;strengthening the building foundation and the bottom of the foundation pit can effectively control the deformation of the building and the foundation pit.