Risk Analysis And Strategies Of Underwater Railway Tunnel Construction With Large Diameter Shield

Abstract:Shield tunnel of the first section of the inter-city rail which connects Changsha with Zhuzhou and Xiangtan locate in the central city, environment of the project is variable that it passes from the bottom of some important buildings and rivers including residential buildings in Yuebei community, building selling tignum, electrical towers, surface roads, underground pipelines, Yinpen Ridge Bridge, Kaifu temple, levee of east and west riverbank of Xiangjiang river, Xiangjiang river et al. Meanwhile, shield tunneling requires advanced technology and it’s difficult to be constructed. There are a lot of high risks in the project. Therefore, in this paper, based on the research project of Ministry of Railways--"Research on Key Technologies of Underwater Railway Tunnel Construction with Shiled", connotations of risk analysis of shield tunneling are studied. WBS-RBS method and fuzzy comprehensive evaluation method are successfully used in the actual project, and reasonable risk control measures are put forward in this paper which has somel reference to the safety control of the construction. The main contents and achievments of the paper are summarized as follows:(1)Shield tunnel project of the first section of the inter-city rail which connect Changsha with Zhuzhou and Xiangtan is very complex, construction procedures are intercross and management system is complicated, risk identification of the project becomes more comprehensive that pivotal sources of risk are identified by using of WBS-RBS method which makes analysis hierarchy become more clearly and the process of identification tend to quantitative;(2)Taking full account of the principles of risk system establishing, the reasonable risk assessment systerm are set up by using Analytic Hierarchy Process method, and risk evaluation criterias are set up based on features of the inter-city rail which connect Changsha with Zhuzhou and Xiangtan;(3)Considering of the ambiguity of risk measurement, multi-level fuzzy comprehensive evaluation model is used to classify the risk in the project accurately which combine qualitative analysis and quantitative methods, and risk controlling measures are put forward against the construction when shield tunnel passes from the bottom of residential buildings in community, Yinpen Ridge Bridge, levee of east and west riverbank of Xiangjiang river and stratum of unconformity contact under Xiangjiang river.