结合拟拆除现状结构的多级基坑围护应用研究

Application Study on Multistage Excavation Support Structures Combined with Demolition of Existing Structures

结合拟拆除现状清水池结构对上海泰和水厂新建提升泵房及臭氧接触池进行了基坑围护设计与施工,形成“放坡-拟拆除现状结构-放坡”和“放坡-拟拆除现状结构-灌注桩”两种三级基坑围护形式。对该围护形式设计思路及施工过程进行了介绍和研究,并对周边环境影响、围护结构变形进行了有限元分析和现场实测。结果发现坑外地表沉降和围护结构最大侧向变形均在规范要求范围内,施工过程中基坑安全可靠。相比于传统围护方式,该围护形式可节约造价,加快工程进度,为传统基坑设计提供新的思路。

Excavation engineering of newly built lifting pump house and ozone contact tank in Shanghai Taihe Water Works was designed and constructed combined with current clean water tanks to be demolished.Two types of three-level excavation support structures which include "sloped excavation-current structuressloped excavation" and "sloped excavation-current structures-pile wall" were raised.Design and construction process of the two types of three-level excavation support structures were introduced and studied.Finite element analysis and field measurement were carried out to study the impact on the surrounding environment and deformation of excavation support structures.The results showed that ground subsidence outside wallboard and lateral deformation of excavation support structures were within the scope of the specification.The multistage excavation support structures were safe and reliable during construction.Compared with traditional way of retaining wall,the cost of projects were greatly reduced and the progress of projects were speeded up,which would provide a new idea for foundation pit design.