基于SEM-MC的地铁车站深基坑施工危险性测度研究

Research on risk measurement of deep foundation pit construction in metro station based on SEM-MC

为提高地铁车站深基坑施工危险性测度的准确性,考虑多风险因素耦合作用和危险性测度主观性对传统风险评测结果的影响,提出基于结构方程(SEM)与蒙特卡洛模拟(MC)相结合的地铁车站深基坑施工危险性测度方法。首先,从基坑支护、基坑开挖、降水排水以及周边环境4个维度建立危险性测度指标体系,利用SEM确定指标权重,并确定关键因素;然后,根据指标的数据分布特征,利用MC法模拟出潜变量值并与风险损失程度、指标权重相结合得出危险度;最后,将该危险性测度方法运用于南昌地铁双港站。研究结果表明:该地铁车站深基坑风险等级为4级,基坑开挖为该地铁车站深基坑施工主要风险影响因素,其直接影响因素为开挖技术参数设置。项目实施结果表明该方法对地铁车站深基坑施工危险性评测适用可信。

In order to enhance the accuracy of risk measurement on the deep foundation pit construction in metro station,considering the influence of the coupling effect of multiple risk factors and the subjectivity of risk measurement on the results of traditional risk measurement,a risk measurement method for the deep foundation pit construction in metro station based on the combination of structural equation modeling(SEM)and Monte Carlo simulation(MC)was proposed.Firstly,an index system of risk measurement was established from four dimensions of foundation pit support,foundation pit excavation,precipitation and drainage,and surrounding environment,then the weights of indexes were determined by using SEM,and the key factors were determined.Secondly,according to the data distribution characteristics of indexes,the values of latent variables were simulated by using MC method and combined with the risk loss degree and index weights to obtain the risk degree.Finally,the method of risk measurement was applied to the Shuanggang Station of Nanchang Metro.The results showed that the risk grade of deep foundation pit in this station was Grade IV,the foundation pit excavation was the main risk influencing factor of deep foundation pit construction in this metro station,and the direct influencing factor was the setting of excavation technical parameters.The implementation results of project indicated that this method is applicable and reliable for the risk measurement on the deep foundation pit construction in metro stations.