软土地铁深基坑开挖过程中围护侧向变形控制方法研究

在周边环境较为复杂的软土地区,基坑开挖变形稍大就会对临近建(构)筑物产生不利影响。影响基坑变形的因素众多,但诸如结构刚度、支撑布置(道数与间距)等因素在设计阶段已确定,施工过程中可调控的因素较少。从支撑轴力与软土流变的角度, 探讨基坑开挖过程中围护侧向变形的控制方法。从软土地铁深基坑支护体系的力学特点出发,系统研究该体系的力学状态和作用机制,针对基坑开挖过程中无支撑暴露/ 有支撑暴露不同情况提出围护结构侧向变形控制方法。同时,结合实际工程,对该控制方法进行具体的施工应用研究。实践结果表明,该方法对地铁深基坑围护侧向变形控制具有显著效果。

Control Methods for Lateral Deformation of Retaining Structure of Deep Foundation Pit in Soft Soil

In soft soil areas where the surrounding environment is relatively more complicated, the deformation of the foundation pit will have a negative impact on adjacent structures. There are many factors affecting the deformation of the foundation pit, but factors such as structural rigidity, support arrangement (number of rows and spacing) have been determined in the design stage, and there are few factors that can be adjusted in the construction stage. The control method for lateral deformation of foundation pit during excavation are discussed from the perspective of supporting axial force and soft soil rheology. Based on the mechanical characteristics of the deep foundation pit supporting system in soft soil, the mechanical state and control mechanism of the system are studied systematically. The lateral deformation control methods for the retaining structure are proposed for the foundation pit under different conditions with and without support exposure. Meanwhile, the methods are applied to projects, and the applical results show that the method has a significant effect on the lateral deformation control of the deep foundation pit.