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软弱地层条件下,地铁车站深基坑施工在围护结构施工、开挖施工、主体结构施工阶段的变形规律和失稳状况比一般地区城市深基坑更加复杂,具体表现为施工期间的深基坑围护结构与主体结构对周边环境会产生不良影响,易引起较大的地表沉降,给工程施工造成重大安全隐患。为解决这一问题,以大连地铁某车站为研究对象,首先,基于FLAC3D构建该地铁车站深基坑数值分析模型,模拟施工开挖过程,分析软弱地层地铁车站深基坑变形特征及地表沉降趋势;然后,根据仿真数据与现场实际监测数据的对比,进行深基坑开挖过程安全性分析,绘出地表沉降对比分析曲线,给出深基坑工程引起地表沉降变化的动态趋势,探讨软弱地层地铁车站周围地表沉降预测方法。结果表明,基于钢支撑与地下连续墙相结合的软弱地层深基坑围护结构可有效维持土体平衡,约束土体变形。
Under the conditions of weak strata, the deformation and instability of the deep foundation pit construction in the subway station construction and excavation construction of the envelope structure are more complicated than the deep foundation pit in the urban areas in general, which is manifested as the deep foundation during the construction period Pit enclosure structure and the main structure of the surrounding environment will have a negative impact, easy to cause a large surface subsidence, the construction of a major security risk. In order to solve this problem, taking a subway station in Dalian as the research object, firstly, the numerical analysis model of deep foundation pit of subway station is constructed based on FLAC3D to simulate the excavation process and analyze the deformation characteristics of deep foundation pit and the tendency of surface subsidence in metro station Then, based on the comparison between the simulation data and the actual monitoring data in the field, the safety analysis of deep foundation pit excavation process is carried out and the curve of surface settlement comparison is drawn. The dynamic trend of surface settlement caused by deep foundation pit excavation is given. Surface Subsidence Prediction Methods Around Metro Stations. The results show that the retaining structure of deep foundation pit based on the combination of steel support and diaphragm wall can effectively maintain the balance of soil mass and restrain the deformation of soil mass.