软土地区大型深基坑总体设计与施工方案

以某软土地区深大基坑工程为背景,分析了该项目周边环境的复杂性、多样性及基坑施工的难点。论述了该类基坑多种支护方式组合应用的必要性与可行性。研究表明:当基坑面积较大时,采用中间盆式开挖,利用先期完成的中部主体结构作为支撑支点,并根据坑深的不同采用1~2道竖向钢斜撑,可减少支撑工程量并有效地确保基坑稳定;砂性软土地区的施工场地开阔时,深度7 m左右的基坑可采用两级放坡的方式直接开挖;砂性软土地区的施工场地狭小时,深度9 m左右的基坑可采用1道竖向钢斜撑结合坑内加固及换撑的支护模式。

Overall Design and Construction Scheme of Large Deep Foundation Pit in Soft Soil Area

Taking a deep foundation pit project in soft soil area as the background,the complexity and diversity of the surrounding environment of the project and the difficulties of foundation pit construction are analyzed.This paper discusses the necessity and feasibility of the combined application of various supporting methods for this kind of foundation pit.The research shows that when the foundation pit area is large,the middle basin excavation is adopted,the middle main structure is used as the support fulcrum,and 1-2 vertical steel diagonal bracings are adopted according to the different depth of the pit,which can reduce the support engineering quantity and effectively ensure the stability of the foundation pit.When the construction site is open in sandy soft soil area,the foundation pit with a depth of about 7 meters can be directly excavated by two step-slope.When the construction site in sandy soft soil area is narrow and the depth of foundation pit is about 9 meters,the supporting mode of one vertical steel diagonal bracing combined with pit reinforcement and support replacement can be adopted.