Risk Analysis And Evaluation Of Diversion Tunnel's Construction Stage In Water Diversion Project

There are many rivers and lakes in China,but the distribution of water resources is concentrated in the Jianghuai and other southern regions.The construction of long-distance trans-basin water transfer projects can effectively solve the growing shortage of water resources in the northern region.The diversion tunnel is an important part of the trans-basin water transfer project.It is an indispensable project to complete the long-distance water transfer task across the region.It is affected by multiple factors such as engineering geology,surrounding rock conditions,construction technology,etc.There are many risk factors,which have high requirements on construction technology,scheme design,and staffing.How to control and prevent risks in the construction phase of a diversion tunnel has become an issue of increasing concern in recent years.In this paper,the 4# water diversion tunnel of the first phase in the water diversion project is taken as the research object,and the risk analysis and evaluation during the construction phase of the diversion tunnel is the research objective.The risk of the construction phase of the diversion tunnel is identified through the work Breakdown Structure and Risk Breakdown Structure.The risk evaluation index system for the construction phase of the diversion tunnel is considered from three aspects: natural risk,technical risk,and organizational management risk.Then the weights of all levels and comprehensive weights of risk assessment indexes are calculated by AHP,taking the grey whitening weight function clustering method as the risk evaluation model,the paper evaluates and analyzes the risk in the construction stage of the 4# diversion tunnel of the first phase project of water supply from Taohe River.According to the division principle of risk level,the risk level of the construction stage of 4# diversion tunnel in the first phase of Taohe water supply project is obtained,and the results of risk assessment are analyzed,the risk factors in the construction stage of the diversion tunnel are summarized,and the corresponding risk response measures are put forward,The specific research contents are as follows:(1)Risk theory of diversion tunnel.Through understanding the risk research status of the tunnel project at home and abroad,analyzing the existing deficiencies in the current research,summarizing the characteristics of the risk in the construction stage of the diversion tunnel,comparing the advantages and disadvantages of the commonly used methods in the risk identification and risk evaluation of the diversion tunnel and the applicable conditions,providing theoretical support for the risk evaluation in the construction stage of the diversion tunnel.(2)Risk assessment index system of diversion tunnel construction stage.This paper makes statistics of all kinds of construction accidents in tunnel construction from 2008 to 2018,analyzes all kinds of risk factors in the construction stage of headrace tunnel from various angles,and establishes the risk evaluation index system of the construction stage of Headrace Tunnel with WBS-RBS method.(3)Risk assessment of diversion tunnel construction stage.According to the characteristics of risk factors in the construction phase of the diversion tunnel,combined with the actual situation of the construction phase of the first phase of Taohe water supply project 4# diversion tunnel,The weight of each risk factor is determined by the analytic hierarchy process(AHP),and the risk of the construction stage of the 4# diversion tunnel in the first phase of water supply project is evaluated by combining with the grey theory.The result of risk assessment in the construction stage of 4# diversion tunnel in the first phase of Taohe water supply project is medium risk,which is consistent with the actual situation of the project.The applicability of risk analysis and assessment model in the construction stage of diversion tunnel based on AHP and grey theory is verified.(4)Risk response measures.Through the analysis of the risk assessment results of the diversion tunnel construction stage,Detailed risk response measures for high-risk factors in the construction process and risk prevention measures for medium risk factors are proposed.For the low risk factors,it is suggested to avoid the risk through standardized construction process.