Construction Risk Evaluation Study Of No.2 Water Diversion Tunnel Of Tianshui Urban Area Diversion Water Supply Project

With the rapid growth of my country’s economy and an increasing number of long-distance water delivery projects,tunnel projects are key buildings in these projects and common forms to transport water across the mountains.Tunnel projects in operation are invariably influenced by complicated geologic environment,complex operational procedures,narrow operational aspects,long-term operational cycle,considerable potential risks and many other factors.These increase more potential risks in the operation and the incidence of emergencies.Therefore,we need to recognize,analyze and evaluate the risks occurring in the operational cycle of tunnel projects,which will be of great significance to ensure the smooth development of these projects.Taking as the research object the 2~#water supply project from Yao River in the urban district of Tianshui City,this passage recognizes the operational risks in tunnel projects combined with Delphi method and risk breakdown structure(RBS)by the process of recognition,analysis and evaluation,thus coping with the risks occurring in the course of operation.Adopting the analytic hierarchy process and grey cluster method for risk analysis and evaluation,this passage finally defines the risk rank of 2~#tunnel project.In the phase of risk recognition,it integrates Delphi method which will be helpful to carry out questionnaires on experts with RBS to analyze operations risks of these tunnel projects stage by stage using risk analysis structural method.After analysis and collection of questionnaire results,we come to six aspects,24 risk indicators in the end which comprise a risk evaluation indicator system of tunnel projects.In the risk evaluation,this passage utilizes the combined analytic hierarchy process and grey cluster method to establish a risk evaluation model in the operation of tunnel projects based on AHP-Grey.In the phase of risk case,this passage talks about the general situation,geologic conditions and operational methods,and analyzes the main risk problems from six aspects.With AHP-Grey model,it analyzes and calculates to get the weight in various levels of indicator system which will be combined with Delphi’s third-round expert score,divided into 5 gray scales and preceded by gray clustering analysis to finally calculated results,obtained the risk evaluation level of the 2~#tunnel project,and put forward some measures for some risks.It is hoped that this research will provide some reference for the risk identification and response during the construction period of the long-distance water tunnel with phase conditions and the same type.