摘要
邻近环境敏感设施的基坑围护结构设计多采取增加围护墙嵌固深度、增加坑内地基加固、基坑外设置隔断墙等措施对周边环境予以保护,造成的工程费用增加、工期延长等问题存在优化的可能。目前基坑工程的设计优化主要集中于围护墙的类型及构件的优化,缺少对整个基坑围护体系整体方案的优化研究。以与运营中的地铁车站及大直径雨水管相邻的建筑地下室基坑及地铁连通道基坑设计为例,以确保地铁车站及周边环境安全为目标,对基坑围护体系的设计方案进行了比选优化,分析采用三维有限元方法模拟实际开挖工况,并根据土体在不同阶段的受力特点,在初始应力状态分析及开挖过程模拟阶段对土体赋予不同的弹性模量。结果表明:对原设计方案进行了取消临时封堵墙,地下一层区与地下二层区同步施工的优化设计后,基坑周边建、构筑物安全,获得了安全、经济的方案。
The increase of embedded depth of retaining wall, reinforcement of foundation soil and set-up of partition wall between foundation pits and buildings are widely-used techniques to protect the surrounding facilities. The problems of budget and construction period can be possibly reduced by optimization design. Currently, the optimization design of the foundation pits focuses mainly on types of retaining wall and structural members and not on the whole retaining system. Based on a deep foundation pit close to a metro station in operation and a large-diameter water pipe, a 3D finite element model is proposed. The behaviors of soils are assumed to conform to Drucker-Prager model, and three different construction sequences are simulated. Considering the distinct stress states of soils during construction, loading and unloading modulis of each soil type are adopted. The results show that the implementation of the temporary partition wall can be canceled, and the basement floor No. 1 and No. 2 can be excavated downward simultaneously. The design of retaining system is optimized, and the settlement-sensitive municipal facilities are safe.
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2014年第S1期39-45,共7页
Chinese Journal of Geotechnical Engineering
关键词
深基坑
有限元法
封堵墙
方案优化
deep foundation pit
finite element method
partition wall
optimization design
