Study On Risk Analysis And Countermeasures During Construction Period In The Yellow River Crossing Tunnel Of The Middle Route Project Of South-to-north Water Diversion

With the rapid development of tunnel and underground works in our country, theconstruction of tunnels under water have entered into a developing period, such as largesubaqueous tunnels in Shanghai, Wuhan, Nanjing, Guangzhou and Hangzhou, drainageand inlet tunnels of power plants along the rivers or seas, tunnels of gas transmission inChangjiang River Area and water conveyance tunnel in the Yellow River basin. Theconstruction operation of special undermining driving constructions underground orunderwater is usually completed by shield machine. As well as the complicated andunpredictable geological conditions, the project may face greater risks and dangersduring the construction. Therefore, performing risk analysis on tunnel and undergroundworks during the construction is of great significance.First, the paper analyzes the present conditions of researches on risk managementin the field of tunnel and underground works at home and abroad. And it also illustratesthe relevant theories and techniques of risk management in the field of tunnel andunderground works.Secondly, the paper discussed the common accident types and the characteristics inthe underwater tunnels, and the applicable principles for selection of constructionmethods. The common risk factors under the construction of underwater tunnels areidentified by Delphi Method, Fault tree analysis and related standards on riskmanagement of underground works. The main risk factors identified is divided into thehierarchical structure based on analysis of hierarchy process, and their weights are alsodetermined. A risk analysis model is established for all the risk factors identified basedon Fuzzy comprehensive evaluation finally.Thirdly, based on the Yellow River crossing tunnel of the middle route project ofSouth-to-North water, the risks in the construction are analyzed by Fuzzycomprehensive evaluation. The level of risks for the main risk factors identified and thewhole project during the construction stage are determined. Finally, some prevention ofrisks is raised and the development prospect of the risk management is looked forward.