基于三维有限元的地下连续墙深基坑逆作法施工方案设计

基于三维有限元,对采用"逆作法"施工的地下连续墙深基坑进行了设计方案研究,按变形控制提出了设计方法,并以天津某基坑为例进行了计算.首先,对结构进行了竖向荷载作用下的结构设计计算,然后,在结构计算的基础上提出了3种基坑施工方案,分别建立了三维有限元模型.对各方案的不同工况进行计算模拟,获得了各方案在不同工况下的连续墙和楼板的应力应变结果,找出了施工的控制工况和受力的薄弱部位.最后,结合实际情况分析了各方案的优点和不足之处,对方案进行了优选,可为最终设计方案的确定提供参考.

Construction scheme design for deep foundation pit constructed by "top-down" method based on 3D FEM

Construction scheme design of diaphragm wall deep foundation pit constructed by “top-down” method based on 3D FEM is researched; and design method according to deformation control is put forward. The oversized deep foundation pit of Hutchison Whampoa Ltd. project in China’s Tianjin is calculated and designed as an example. Firstly, structure design of the slabs under vertical load is done. Secondly, three design schemes are put forward based on the structure design and 3-D FEM models of which are established; and every state of each scheme is calculated respectively. The stress and deformation of the diaphragm and slab under different states are obtained. The key state of construction and the weak parts of the whole structure are found out. At last, with consideration of the practical situation, advantages and deficiencies of the schemes are analyzed. Optimal scheme is selected by synthetical consideration.