地铁车站支护与主体结构相结合深基坑变形

依托济南某地铁车站基坑工程,建立考虑土与结构共同作用的三维数值模型,模拟支护结构与主体结构相结合的基坑施工全过程,研究基坑的围护桩侧移、坑外地表土体沉降和坑底土体回弹规律。结果表明:随着开挖深度的增加,围护桩向基坑内部运动,且最大侧移沿桩身逐渐增大,最大值为开挖深度以上1 m左右;混凝土立柱的存在会明显加大围护结构的整体刚度,进而减小围护桩的侧移;基坑外侧最大沉降发生在约为1/2基坑宽度的区域,周边土体沉降范围约为4倍支护深度;混凝土立柱能减小基坑底部土体的回弹。采用支护与主体结构结合的方式,可以减小基坑在施工过程中的变形。

Deformation of Deep Foundation Pit Combining Support and Main Structure in Subway Station

Based on the foundation pit project of a metro station in Jinan,a three-dimensional numerical model considering the interaction of soil and structure was established.The whole process of foundation pit construction combined with support structure and main structure was simulated to study the lateral displacement of retaining piles,surface soil settlement outside the pit and soil rebound at the bottom of the foundation pit.Results show that with the increase of excavation depth,the retaining pile moves to the inside of foundation pit.The maximum lateral displacement increases gradually along the pile body,and the maximum value is at about 1 m above the excavation depth.Concrete columns will significantly increase the overall stiffness of the retaining structure,thereby reducing the lateral displacement of retaining pile.The maximum settlement outside the foundation pit occurs in the area about 1/2 of the foundation pit width.The settlement range of surrounding soil is about 4 times the supporting depth.Concrete columns can reduce the rebound of soil at the bottom of foundation pit.The deformation of the foundation pit in the construction process can be reduced under the combination of supporting structure and main structure.