Safety Risk Coupling Study Of Utility Tunnel Construction In Collapsible Loess

China is in the period of rapid urbanization,and the number of various municipal pipelines keeps increasing.The utility tunnel can incorporate all kinds of pipelines into the corridor for overall planning,which can not only effectively utilize the underground space,but also improve the city’s ability to prevent disasters and improve the city’s functions.The utility tunnel construction often face uncertain conditions and the environment such as a long construction period,deep foundation pit excavation,crossing existing buildings.In addition,safety risk of utility tunnel construction in collapsible loess area is different from other ordinary geological region,safety accidents occurred more often in the construction process.However,the occurrence of these accidents is not only caused by a single risk factor such as special geology,environment or inadequate management,but also caused by the interaction of multiple risk factors.At present,the research on coupling risk has been extended to many fields by domestic and foreign scholars,but there are relatively few theoretical studies on the coupling effect between the utility tunnel construction safety risk factors in collapsible loess areas.Therefore,this article will systematically study construction safety risk coupling mechanism of utility tunnel in collapsible loess area,find the rule of the formation of coupling risk and put forward risk control strategy based on the idea of risk discoupling.The results of the study for utility tunnel in collapsible loess area for the reference of the construction site safety management and risk control.The main contents of this paper are:First of all,this paper based on the theory of risk analysis and risk on the coupling theory,studies the characteristics and classification of utility tunnel construction safetyrisk and the risk of construction safety coupling in collapsible loess area.And the coupling effect mechanism of risk factors was analyzed from five dimensions,including human factors,machinery &materials factors,environment factors,management factors and construction technology factors.Secondly,we constructed the model of multiple risk factors coupling degree based on entropy weight-DEMATEL,by using the coupling model to quantitatively analyze the coupling relationship between safety risk factors during the construction of utility tunnel in collapsible loess area.On this basis,combining the theory of system dynamics,this paper established the human-environment factors coupling system dynamics model of utility tunnel in collapsible loess area,using Vensim PLE software for simulation.By sensitivity analysis,the influence of risk factors on the development trend of risk level of human-environment factors coupling system is dynamically observed,and it proves the applicability of the model.Finally,this paper based on the principle of safety risk discoupling,the risk control strategy is put forward from the early,middle and later stages of coupling,which further improves the research theory of safety risk coupling in the utility tunnel construction in collapsible loess area.