软土地区紧邻民居的深基坑逆作法设计与实践

Design and Application of Top-down Method in a Deep Excavation Adjacent to Residential Buildings in Soft Soil District

本文介绍了逆作法在上海市区某紧邻民居的软土基坑工程中的设计与应用。重点介绍了总体设计方案、周边围护结构设计、竖向支承桩柱设计以及异形柱剪力墙结构体系的地下室首层结构梁板的受力分析与设计。基坑实施结果表明,逆作法节省临时支撑,水平刚度较大,有效控制了基坑的变形及对周边环境的影响,暗挖土方极大程度地减少周边居民的心理恐惧与担忧,取得了良好的技术、经济和社会效果,可为类似工程设计和施工提供借鉴。

This paper introduces the design and application of the top-down construction method in a foundation pit in Shanghai soft soils. The excavation was adjacent to residential buildings and it had strict environmental protection and stability maintaining requirements. Emphases were put on the overall design scheme,design of the retaining wall,the vertical supporting system,and design and analysis for the first floor with the special-shaped columns frame-shear structure system.The successful completion of the project showed that the top-down method saved temporary struts and effectively controlled the impact on the surrounding environment due to substantial horizontal stiffness. The underground soil excavation measures greatly reduce the psychological fear and worry of the surrounding residents. Moreover,good technical,economic and social effects were obtained. Design of this deep excavation can provide reference for similar projects.