上海地区某基坑开挖阶段的位移与受力分析  

Displacement and stress analysis of a Shanghai foundation pit at excavation stages

作　　者：任东兴 黄海 邵康[2] 刘欢欢 罗东林 薛鹏 REN Dongxing;HUANG Hai;SHAO Kang;LIU Huanhuan;LUO Donglin;XUE Peng(Chengdu Surveying Geotechnical Research Institute Co.,Ltd.of MCC,Chengdu 610023,China;School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China;Sichuan Energy Saving and Environmental Protection Investment Co.,Ltd.,Chengdu 610023,China)

机构地区：[1]中冶成都勘察研究总院有限公司,成都610023 [2]西南交通大学土木工程学院,成都610031 [3]四川能投节能环保投资有限公司,成都610023

出　　处：《建筑结构》2022年第16期116-124,共9页Building Structure

基　　金：国家自然科学基金(51808458)。

摘　　要：以上海地区采用顺作法施工开挖深度为20.8m的建筑基坑为研究对象,对五个施工阶段的地下连续墙侧向和竖向位移,立柱竖向位移和混凝土支撑轴力进行监测,以围护结构的侧向变形随深度、位置和施工阶段的差异分析基坑变形呈现的空间效应与深度效应,以立柱和地下连续墙的竖向变形规律分析基坑回弹特征,以混凝土轴力随时间变化规律分析支撑在各施工阶段的关键作用。分析结果表明:地下连续墙在远离坑角位置比靠近坑角位置侧向位移更大,最大侧移范围为开挖深度的0.12%~0.41%,其侧向位移沿深度呈现“肚胀”形曲线,最大侧向位移发生在开挖深度以上4m到以下2m范围内;地下连续墙和立柱竖向位移主要以隆起为主,地下连续墙最大隆起位移为9.14mm,立柱最大隆起位移为地下连续墙的4倍;混凝土支撑对于下一阶段开挖起着关键作用,但对更深处土层开挖影响较小,混凝土支撑轴力最大值与地下连续墙的侧向位移密切相关。Taking a foundation pit with the construction excavation depth of 20.8 m in Shanghai as the research object, the lateral and vertical displacement of the underground diaphragm wall, the vertical displacement of the stand column and the axial force of the concrete support in the five construction stages were monitored. The spatial effect and depth effect of the foundation pit deformation were analyzed by the lateral deformation of the enclosure structure with the difference of depth, location and construction stage, and the springing back characteristics of the foundation pit were analyzed by the vertical deformation law of the stand column and the underground diaphragm wall. The key role of support in each construction stage was analyzed based on the law of force variation with time. The analysis results show that the lateral displacement of the underground diaphragm wall is larger at the position far from the pit corner than near the pit corner, and the maximum lateral displacement range is 0.12% ~ 0.41% of the excavation depth;its lateral displacement presents a bulging curve along the depth, and the maximum lateral displacement occurs in the range of 4 m above the excavation depth to 2 m below;the vertical displacement of the underground diaphragm wall and stand column is mainly uplift, the maximum uplift displacement of the underground diaphragm wall is 9.14 mm, and the maximum uplift displacement of the stand column is 4 times that of the underground diaphragm wall;concrete support plays a key role in the next stage of excavation, but has little effect on the excavation of deeper soil layers, and the maximum axial force of concrete support is closely related to the lateral displacement of the underground diaphragm wall.

关 键 词：基坑开挖 地下连续墙 立柱 侧向变形 隆起和沉降 施工监测 空间效应 深度效应 

分 类 号：TU753[建筑科学—建筑技术科学]