Risk Assessment And Control Strategy For Slurry Balance Shield Tunnel Crossing Complex Environment

In the construction of urban subways in China in recent years,due to the small impact on the environment caused by shield construction,it is not restricted by terrain,landform,rivers and other conditions,as well as the safety and speed of construction,and has been obtained in many cities in China.Widely used,this paper takes the tunnel of mud-water balance shield mechanism as the research direction.However,the construction of shield tunnels is still a large underground project.In the process of construction of mud-water balance shield machinery,there is insufficient understanding of construction risks.Without scientific risk assessment tools and lack of scientific risk management system,construction accidents will occur.Although the construction risk management of shield tunnels has developed to a certain extent,it still cannot meet the needs of construction.The serious risk consequences of major accidents and engineering functions failing to meet the standards often appear in tunnel construction in China.Engineering risk management as a complex system emphasizes integrity,information transfer and circulation,and scientific management.Through the use of mathematical methods,the risk is quantified,and then high-risk events are selected for evasion.This paper takes Wuhan Railway Transit Line No.8 Phase I Civil Engineering Three-standard Huangpu Road Station-Xujiapeng Station Cross-river Shield Tunnel Project as the background.Based on a large number of literature books,it encounters complex terrain during the construction period of mud-water balance shield construction.Scientific research on risk identification,analysis and evasion of the working conditions,the main contents are as follows:1.Establish a dynamic tunnel construction risk analysis system based on the characteristics of mud-water balance shield construction.The construction risk management organization system based on Bell's living system theory was optimized.The two types of pregnancy environment of mud-water balance shield crossing complex terrain are identified,and the fault tree analysis model of different pregnancy and danger environments is established by using fault tree analysis method.2.Information collection on the risk probability and economic loss ratio of the risk event of the mud-water balance shield during construction was carried out,and relevant experts were invited to conduct the evaluation and scoring.Based on fuzzy mathematics theory,the fuzzy confidence index method is used to optimize the risk probability and economic loss ratio of tunnel risk events,and then the optimal risk matrix of each risk event in mud-water balance shield construction is obtained.3.Using MATLAB software to establish a mud-water balance shield tunnel construction risk analysis analytic hierarchy judgment judgment matrix mathematical model,entropy method mathematical model,BP neural network mathematical model based on differential quotient derivative quotient improvement,respectively calculate the risk events Weight or comprehensive score or difference quotient instead of derivative quotient as the importance of the event;according to the ranking of the importance of each risk event of the three methods,the top three risk events are found;the summary is summarized,and the comprehensive needs to be circumvented High-risk events.4.The technical measures and countermeasures for the effective avoidance of six risk events under the existing structure section and the complex terrain section crossing the river bottom are proposed and applied to the project implementation,which provides the engineering construction safety with Risk management system,technical theory and avoidance measures for engineering application value.