Research On Risk Assessment And Its Application In Mountain Railway Tunnel Construction

The Ministry of Railway issued the "Interim Provisions of the Risk Assessment and Management of Railway Tunnels" in November,2007, which is however a set of provision lacking support of theory and methodology, implementation guidance and practice examples. The thesis carries out researches on management pattern and key assessment technique specifically targeted for the construction of mountain railway tunnels in China, in combination with the scientific research project of Railway Bureau of Nanchang titled "Research on the Risk Management Mode of Construction of Railway Tunnels" and the commissioned project from Xiangpu Railway Company named "Research on the Risk Management and Assessment of the Construction of Xiangpu Railway tunnel", coming out with the definition of the risks of mountain railway tunnel construction, a design of the risk assessment pattern and the corresponding performance analysis after its implementation in mountain railway tunnel construction. The thesis has successfully quantized the assessment of the risks in mountain railway construction, scientized the target of assessment, functioning as a reference to the risk assessment and management of the railway tunnels construction. The feasibility of the research result is verified with the case of the Qingyun mountain railway tunnel. The main content of the research and innovations are as follows:Firstly, in the process of the construction of mountain railway tunnel construction, human, machines, environment and management these four factors work together, changing the risk level in construction. Based on this reorganization, the thesis puts forward the definition of the risks of mountain railway tunnel construction, with a probe into the mechanism of the occurrence of risks and the establishment of the risk assessment pattern of mountain railway tunnels construction.Secondly, in consideration of the complexion, variety and effectiveness of the factors causing disasters as well as the impact to the project, the thesis carries out researches based on the human-machine-environment-management system. With the system of disasters causing factors of the risk assessment of mountain railway tunnels construction set up, the thesis could provide reference for the risk assessment as a result.Thirdly, the thesis advances PRCA mountain railway tunnel risk management pattern to improve the active role of the managing factors in human-machine-environment-management, reaching the goal to decrease the construction risk. On the basis of the relations between management factors with human, machine, and environment, the thesis establishes performance evaluation index system for PRCA management pattern and introduces evidence-based Dempster-Shafer theory, carrying out PRCA risk-management performance evaluation research, and setting up a performance calculation model under PRCA management pattern.Fourthly, the thesis builds up a Fuzzy-AHP (Fuzzy-Analytical Hierarchy Process) pattern to analyze the railway tunnel construction risk. It puts forward the accident consequential classification method for railway tunnel construction on the basis of economic value measurement and introduces "Equivalent" concept as a result. It further proposes to solve the accident consequential evaluation problems of mountain railway tunnel construction with construction consequential equivalent evaluation method. It builds up a risk assessment pattern based on risk-management performance calculation.Lastly, the author, by exploring the research achievements in construction risk assessment of mountain railway tunnel from this thesis and taking Qingyun mountain railway tunnel as an application case, studies on the implementation of PRCA management pattern and assesses the Qingyun mountain railway tunnel construction risks. Research shows that the construction risk for Qingyun mountain railway ranks at Grade IV which belongs to a reasonably degradable area. After applying the PRCA risk management pattern, the risk has been lowered to Grade II for the reassessment, and the results are significant.