基于监测数据的某地铁基坑工程安全风险模糊评价

Fuzzy evaluation of safety risk based on the monitoring data of a subway foundation pit engineering

结合某大型地铁车站基坑工程施工不确定因素多的复杂特征,将该基坑工程安全风险因素划分为基坑本体结构与周边环境两部分。其中基坑本体结构的风险因素为深层水平位移、支撑轴力、锚索拉力、围护桩顶水平位移和地下水位;周边环境的风险因素为地表、建筑物、桥梁、道路的沉降。以累计变化和变化速率作为上述9个因素的风险评估模型数据,根据其相应允许值,作为将基坑划分为4个安全等级的依据,然后根据隶属函数确定各层评价因素所处的风险等级,综合基坑本体结构与周边环境的权重及模糊隶属值确定该基坑为一级风险状态,给出施工时应对基坑工程施工安全进行关注的结论。

Combined with a large Metro Pit engineering which is with complexity and the uncertainties,the safety risk factors are divided into two groups,the pit body structure and the surrounding environment.The risk factors of pit body structure includes the displacements of the deep level,strut axial forces,the anchor cable tension,the horizontal displacement of the top retaining pile and groundwater level;risk factors of the surrounding environment includes subsidence of ground surface,buildings,bridges,and roads.Accumulated deformation and rate of change of the above nine factors are used to build the risk assessment model.According to the corresponding allowable values,four security levels are defined for the pit safety.The risk level are assessed by membership function with right weights and fuzzy membership values for both the pit body structure and the surrounding environment.