地铁车站深基坑施工变形规律及安全风险评估

Deformation Law and Safety Risk Assessment of Deep Foundation Pit Construction of Subway Station

以苏州市轨道交通S1线帆路站深基坑降水施工项目为工程背景,采用MIDAS GTS/NX建立有限元模型,分析基坑降水开挖过程中地下连续墙变形、基坑周围地表沉降、支撑轴力的变化规律,并对基坑降水施工的安全风险进行评估。结果表明:地下连续墙的变形随深度增加逐渐增大,呈现为中间大、两头小的"勺"曲线型;基坑周围地表沉降分布形态上符合沉降槽曲线,各沉降值均在设计控制范围内;基于贝叶斯网络的故障树模型风险评估法构建简单方便,对于复杂系统,贝叶斯网络模型具有较强的适用性。

In this paper the deep foundation pit project of Suzhou Railway Transportation S1 Line Fanlu Station is taken as the engineering background, the MIDAS GTS/NX is used to establish the finite element model to analyze the change law of continuous underground wall deformation, surface subsidence, support shaft force around the base pit during the excavation of base pit precipitation, and the safety risks of the base pit during precipitation construction are evaluated. The results show that the deformation of the continuous underground wall increases with the increase of depth, and it appears as a spoon-shaped curve of large at middle and small at ends. The surface sedimentation distribution pattern around the pit conforms to the sedimentation trough curve, and each settlement value is within the design control range. The risk assessment method of the fault tree model based on the Bayesian network is convenient and straightforward, and for complex systems, the Bayesian network model has strong applicability.