Study On Life-cycle Risk Assessment System Of Urban Underground Utility Tunnel

With the rapid development of economy and society in our country,the supply pressure of urban infrastructure is increasing day by day.As a variety of engineering pipelines in urban public service system,intensive construction,scientific and orderly management are needed.However,the construction of utility tunnel,which is severed for all kinds of pipelines,needs huge investment,involves wide ranges,has complex maintenance and management,prominent security risks,and lack of experience both in construction and management.Also the supporting policy system is not perfect enough.Therefore,there are many uncertain risks in the construction and operation of urban underground utility tunnel.As a huge infrastructure of city,it is necessary to identify risks,comprehensively analyze and propose measures to avoid risks.This paper aims to fully analyze the various risk factors involved in the process of the construction of utility tunnel,to explore a more scientific,reasonable,effective,and suitable risk assessment methods for the utility tunnel in China,and the specific contents are as follows:Based on the comprehensive analysis of utility tunnel development and research status at home and abroad,understanding the significance of utility tunnel,advantages and disadvantages of the pipe rack,necessity,characteristics of management of construction and operation of comprehensive pipe gallery,as well as the existing problems and risks,obtained the research ideas and data base;Through the analysis of the content of project risk management research,the whole life cycle theory is introduced to divide utility tunnel whole life cycle into five stages,identify the risk factors of each stage,and establish risk index system;Through the study of various risk evaluation methods,take fuzzy comprehensive evaluation method and analytic hierarchy process(AHP)as the main evaluation methods,respectively determine the risk probability and weights in the way of combination of qualitative and quantitative,establish utility tunnel full lifecycle risk evaluation model.According to established risk index system and risk evaluation model,this paper gives risk evaluation to practical projects,analyzes results from three methods:maximum membership degree method,weighted distribution method,and fuzzy distribution method,estimates risk grade of utility tunnel and the magnitude of risk at various stages in whole life cycle of projects,and then proposes strategies for risk aversion at each stage.