（同济大学建筑工程系  上海 200092）
［提要］  以上海恒积大厦基坑逆作法为工程背景，采用Flac有限元计算软件对基坑的逆作施工过程进行了三维模拟，重点模拟了土体结构之间的相互作用。分析了基坑围护墙体的侧向变形和沉降、基坑开挖中楼板的变形以及基坑土体沉降，尤其对基坑开挖过程中立柱和墙体的差异沉降进行了讨论。针对逆作法特有的工程工艺分析了取土孔位置、立柱上浮、差异沉降以及围护墙侧移等工程因素的影响，并提出了相应的控制手段。
［关键词］  深基坑  逆作法  基坑支护  三维分析
Space Analysis on Support of Deep Pit and Topdown Construction/Li Weitao，Ying Huiqing，Ge Peng（Building Engineering of Tongji University，Shanghai 200092，China）
Abstract:Based on the topdown construction of Hengji mansion in Shanghai, Flac software is used to simulate the process of topdown construction，especially the mutual action between soil and structure. The level and vertical displacement of supportwall, deformation of slab and settlement of soil are analyzed in the process of excavation. The difference settlement between piles and supportwall is discussed. Aimed at particular techniques of topdown construction, influence factors including position of soil pore, elevator of pillar, difference settlement and deformation of support wall are analyzed，and the corresponding control method is proposed.
Keywords:deep pit； topdown construction; pit support; space analysis