Study On Risk Assessment Of Urban Underground Complex Based On MCGC From The Perspective Of Whole Life Cycle

With the development of urbanization,the efficient use of land resources and the comprehensive development of underground space are becoming more and more important,and the demand for diversified and complicated urban underground complex is growing.In view of the problems of large-scale urban underground complex,such as lagging urban planning policy,complex engineering project planning,design and construction,and complex multi-management of investment and operation,it is of great significance to construct risk evaluation system and evaluation model from the perspective of the whole life cycle for the risk control of large-scale underground complex.Firstly,on the basis of consulting a large number of relevant literature,this paper summarizes and analyzes the research status and related theories of the life cycle risk of urban underground complex at home and abroad,identifies the key risk factors in the four stages of development,design,construction and operation by using literature review,and preliminarily identifies 27 risk factors.The WBS-RBS method is used to select 16 risk evaluation indexes including management,economy,technology and regulations,including 6 management risk indexes,4 economic risk indexes,3 technical risk indexes and 3 regulation risk indexes.Secondly,the cloud evaluation model is constructed by using the cloud gravity center evaluation method(MCGC).Senior experts in the field of urban underground space construction are invited to use qualitative state language to evaluate,and the qualitative language is converted into quantitative values.The weight of the index is determined by using the three eigenvalues of the cloud model : expected value Ex,entropy value En and super entropy He.Among them,relevant laws and regulations and policies,general planning of underground space,commercial feasibility and willingness to stay,underground engineering environment and construction technology are high or high risk indicators.Finally,using the evaluation index system and model,according to the evaluation criteria of Guangzhou South Railway Station underground complex project overall risk assessment,determine the risk level of the project.The evaluation results show that the overall risk bias of the underground complex project in Guangzhou South Railway Station is serious,and the expert evaluation is consistent with the actual situation,which verifies the effectiveness of the system and model.Strategies and measures are needed to reduce the risk level.The risk evaluation index of urban underground complex is considered and selected according to the whole life cycle.Compared with previous studies,most of them are based on single-stage risk evaluation index research methods such as design,construction safety or operation and maintenance,and the risk index is more comprehensive and systematic.The evaluation model is based on cloud gravity center evaluation method,and the weight is scientific and accurate.The model and weight have good adaptability to the comprehensive evaluation of the system.A case of an underground complex project in Guangzhou is selected,and the grade analysis is obtained according to the risk evaluation system.The case verifies the authenticity and reliability of the evaluation results.The research results can not only enrich the whole life cycle risk assessment theory of underground complex,improve the risk assessment system and evaluation method of underground complex,but also strengthen the indepth understanding of the whole project and all kinds of risks,improve the ability to bear risks,and provide some reference for the government and construction related parties to control the risk of underground complex construction and promote the development of regional industries.