Study on Multi-Level Safety Risk Assessment of Super 40 m Deep Foundation Pit Construction Adjacent to Subway

The construction risk of the deep foundation pit adjacent to the subway is high. The accidents such as collapse occur frequently. The construction risk needs to be assessed before construction. This paper conducts a comprehensive risk assessment on the multi -level risk characteristics and risk indicators of the construction of an over 40 m deep foundation pit adjacent to the subway. The risk is divided into an indicator system, and the analytic hierarchy process is used to calculate the weight of the risk indicators to obtain the objective calculation results. In addition, this paper uses the membership function in fuzzy mathematics to establish risk levels and optimize the evaluation criteria of risk events. The results show that the comprehensive assessment risk value obtained by the optimized risk assessment method in this paper is 3.312, and the risk level is relatively high. According to the risk characteristics, safety measures for the construction process are proposed, which provides a reference for the risk assessment of deep foundation pit projects.