加固体“暗撑”在软土深大基坑工程中的应用

Application of Solid Concealed Bracing in Deep and Large Foundation Pit Engineering in Soft Soil

以临长江、临铁路的武汉项目为例,提出搅拌桩加固作为“暗撑”使用的一种支护措施,用于深厚软土、环境紧张且变形控制严格条件下的基坑工程。该支护措施可有效提高支护结构抗变形能力,降低支护桩桩径及配筋率,方便土方外运,保护工程桩。有限元模拟计算及工程实测数据表明,坑底加固“暗撑”对于支柱桩水平位移约束明显,桩身变形及地面沉降满足相应要求,可为类似基坑工程中的应用提供借鉴。

Taking a project near Yangtze River and railway in Wuhan as an example,the mixing pile reinforcement was used as concealed bracing for supporting in foundation pit engineering under the conditions of deep and weak stratum,limited surrounding environment and strict deformation control.This supporting measure can effectively improve the deformation resistance of the support structure,reduce the pile diameter and reinforcement ratio of the support pile,facilitate the outward transportation of earthwork and protect the engineering pile.The finite element simulation calculation and measured data show that the horizontal displacement of the pillar pile is obviously restricted by the concealed bracing at the bottom of the pit,and the pile deformation and ground settlement meet the corresponding requirements.This research could provide reference for the application of similar foundation pit projects.