External Risk Assessment Of Utility Tunnel In Operation Period Based On Multiple Combination Weighting

With the development of China's economy,cities are also constantly developing and updating,so the demand for infrastructure is higher.In the process of urban development,laying and maintenance of all kinds of underground pipelines will not only cause repeated excavation of the surface,environmental damage,traffic and other problems,but also the difficulty of laying and maintenance.In order to solve the above problems,the utility tunnel is introduced into China.However,because the utility tunnel project is still in the primary stage in China,and the utility tunnel project is mostly laid in the building dense area with high safety level requirements,so it is necessary to conduct a comprehensive study on the risks of the utility tunnel project.As the utility tunnel project is a "Century project" and the guarantee of the normal operation of the city in the future,it is particularly important to study the risk during the operation period of the utility tunnel.This paper mainly studies the external risks during the operation period of the utility tunnel.The results are as follows:(1)According to the analysis of existing utility tunnel projects and similar underground projects,the characteristics of external potential risks during the operation period of utility tunnel are objectivity,concealment,coupling,sustainability,diversity and complexity.(2)In this paper,a large number of relevant literature investigation and interviews with experts on the utility tunnel are used to obtain the list of external risks during the operation period of the utility tunnel.Through the investigation,summary and numerical simulation,the external risk sources in the operation period of the utility tunnel are further studied and analyzed,and the mechanism of the external risks in the operation period of the utility tunnel and the impact law on the safe operation of the utility tunnel are obtained.(3)Due to the complexity and importance of the utility tunnel project,the multiple combination weighting method is created after the study of the existing risk factor weighting method.In this paper,entropy weight method,variation coefficient methodand analytic hierarchy process are used to weight the external risk factors during the operation period of the utility tunnel.The above three methods are dealt with by the ordered weighted averaging operator method.Finally,entropy weight method,variation coefficient method and analytic hierarchy process are combined to get multiple combination weights.Because multiple combination weights combine the applicability of various risk weighting methods in the process of risk assessment,the weight of each risk factor is more reasonable,so it can improve the reliability of external risk assessment results in the operation period of the utility tunnel.(4)In this paper,multiple combination weighting method combined with fuzzy comprehensive evaluation is used to establish the external risk evaluation model of utility tunnel in operation period based on multiple combination weighting.This risk assessment model is used to evaluate the external risk during the operation period of the utility tunnel of Beijing new airport line,and the external risk level is obtained.This paper provides a reference for the study of the external risk during the operation period of the utility tunnel,which is helpful for the development of the utility tunnel in China.