大开口式逆作法深基坑实测变形分析  

Analysis of Field-Monitored Deformation of a Top-down Excavation with Large Size Access Openings

作　　者：徐中华[1] 

机构地区：[1]华东建筑设计研究院,上海200002

出　　处：《地下空间与工程学报》2009年第4期750-756,791,共8页Chinese Journal of Underground Space and Engineering

基　　金：上海市科委重大科技攻关项目:深层地下结构开发关键技术研究(052112010)

摘　　要：上海铁路南站北广场基坑为超大面积深基坑工程,采用大面积出土口的全逆作法施工。简要地介绍了该工程的地质条件、基坑围护方案及施工工况。实测变形结果表明连续墙最大侧移与开挖深度的比值为0.33%;先期基坑开挖显著地影响共用连续墙的变形形态;大面积出土口的设置对连续墙的变形没有明显影响;连续墙的变形速率随着开挖深度的增大而增大,但随着时间的增长而减小,在本层地下水平支撑结构施工完成后变形速率很快衰减至一个很小的值;立柱的竖向位移表现为沉降,并给出了首道水平梁板支撑体系在各工况下的沉降等值线;桩端和连续墙底的注浆措施较好地控制了连续墙和立柱的沉降及其差异沉降。The excavation of the North Square of Shanghai South Railway Station was a deep and large sized excavation. It was constructed by top -down method with large size access openings. The subsurface conditions, supporting system, and construction procedure were summarized. Analysis of the monitored data revealed that the ratio between the maximum lateral displacement of the diaphragm wall and the excavation depth was 0.33%. The prior excavation outside the project significantly affected the deformation behavior of the diaphragm wall. However, the setting of the large size access openings did not have significant effect on the wall deformation. The rate of the lateral displacement of wall increased with excavation depth, while decreased with elapsed time. The rate of the lateral displacement of wall would decrease to neglected values after the construction of the horizontal structure. The center posts were observed to setde during the excavation. Contour plots of the settlement of the first level slab at different excavation stage were given. By applying base - grouting to the piles and diaphragm wall, settlement/differential settlement of the piles and diaphragm wall were effectively controlled.

关 键 词：深基坑 逆作法 大面积出土口 变形 

分 类 号：TU476[建筑科学—结构工程]