坑靠坑支护设计施工技术与开挖影响研究--以上海前滩某项目深基坑为例

Study on Design and Construction Technology of Pit by Pit Support and the Effect of Excavation--Taking a Deep Foundation Project in the New Bund,Shanghai as an example

上海前滩九宫格基坑群为较典型的坑靠坑分布基坑群,基坑特点、地质条件及周边环境具有一定复杂性。分析了该基坑群4个基坑的围护及支撑选型,设计方案采用钻孔灌注桩结合二道砼支撑的围护形式,合理选取基坑加固措施并设计地下水降水处理方案,针对性的制定施工及开挖工况,并对照监测结果分析各基坑相互影响情况,证明先开挖的基坑地下结构施工到一定关键阶段后,相邻基坑开挖不会对其产生显著负面影响,各个基坑的安全性能够得到保障。

The New Bund nine-grid blocks in Shanghai constitute a typical pit-by-pit foundation pit group,and its engineering characteristics,geological and environmental conditions are of certain complexities. Four estates were developed simultaneously and those pits were selected as the research object. Based on the comparative analysis of several popular foundation pit enclosure and supporting methods,the bored pile enclosure system combined with two reinforced concrete supports was adopted in this project,which showed great advantages in safety guarantee and cost control. Reasonable soil reinforcement and dewatering plans were selected,and the excavation process was pertinently designed. By analyzing the monitoring results,the mutual influence of each pit was revealed,and it is proved in practice that the excavation will not have a significant negative effect on the adjoined pit as long as the understructure construction work proceeds to a certain stage,and the safety of each foundation pit can be ensured.