Coupled Analysis And Simulation Of Safety Risks In Metro Tunnel Shield Construction

Currently,China has entered the new stage of the 14 th Five-Year Plan,and the construction of subway tunneling projects has entered a hot development period.Shield method,as one of the common methods of subway tunnel construction,is subject to the coupling of various risk factors such as operators,equipment and materials,construction management and surrounding environment during the construction stage,which makes the safety management of underpass tunnel shield construction a certain risk potential,and domestic and foreign scholars have not yet formed a complete risk management system for the study of risk coupling of underpass tunnel shield construction.Therefore,in this paper,based on the relevant theories of risk management,the typical accident cases of subway tunnel shield construction from2008 to 2022 are statistically summarized,and the specific risk factors of shield construction are identified by combining relevant expert opinions,and the risk coupling system of shield construction is divided into four sub-risk systems: personnel,material,management and environment,etc.The mechanism and role of risk coupling of subway tunnel shield construction are analyzed,so as to establish The risk coupling evaluation index system of metro tunnel shield construction is used to calculate the comprehensive weight value of risk indicators by using AHP-entropy weight method,and the risk coupling degree model is constructed by combining the inverse generator and efficacy function of cloud model to calculate the strength of coupling degree of shield construction risk factors.Combined with the system dynamics,Vensim PLE software is used to establish the construction "human-material" risk coupling system,and the coupling coefficients in the coupling degree model and the comprehensive weights of risk indicators at all levels are brought into the model for dynamic simulation by adjusting the relevant risk coupling coefficients and simulation duration.By adjusting the relevant risk coupling coefficients and simulation duration,we observe the influence of the coupling of various risk factors on the level of safety risk of the human-material coupling system,and analyze that the heterogeneous human-material risk coupling has a significant impact on the system safety risk,and the professional technical level of construction personnel and the risk of shield machine selection,assembly and adjustment are the key coupling factors.This paper collects the safety accident data of underpass tunnel shield construction,summarize the risk factors in the construction stage based on 25 typical cases and expert advice,analyze the mechanism and influence relationship of risk factors in shield construction from the perspective of coupling,establish a risk coupling model,and use system dynamics to study the change of risk level in the "human-material" risk coupling system.Based on the idea of decoupling,the risk control strategy of the three stages before,during and after coupling is proposed,which has certain theoretical value and practical significance to improve the risk management system of underpass tunnel construction.