Study Of Risk Management On The Matro Tunnel Shield Construction

With the rapid advance of the urbanization process, the shield method hasbecome widely used in the metro construction area under some particular geologicalconditions. Metro shield tunnel construction has a long cycle and is largely restricted bythe environmental impact, also, there are still many problems in the construction riskmanagement present. Therefore, we should attach great importance to the riskmanagement research in subway shield construction, analysing and evaluating the metroshield risk and guiding the engineering practice.Firstly, the paper introduces the background, purpose and significance of theresearch, discusses the research status domestic and overseas, and summarizes thecurrent research situation, puts forward the research content, the method and thetechnical route. At the same time, it describes the concept, goal and procedure of riskand risk management and introduces the theoretical foundation of metro constructionrisk management theory and methods.Secondly, the paper introduces the technology of subway tunnel, analyzes theadvantages and disadvantages in shield tunnel construction. Combined with thecharacteristics of subway shield construction, from three aspects of machine,environment and management, it conducts a comprehensive risk source identification atvarious stages of shield by using the methods of expert investigation, flow chart andfishbone diagram, and establishes a comprehensive index system. By using the ISMexplaining structure model, it analyzes the interaction between index factors.Finally, united with the characteristics of the traditional risk analysis method, itdiscusses the applicability of cloud theory for risk analysis, evaluation and control,establishes the risk assessment cloud model. Taking Shanghai Metro Line13as anexample, calculates the index entropy weight. It puts the qualitative evaluation intoquantitative language with cloud expectation, entropy and hyper entropy through cloudfour operations and weighted synthesis, realizes the overall risk evaluation and putsforward the corresponding strategies. The risk possibility and extent of damage can beanalyzed in the model integrately. It can overcome the subjectivity in the determinationof the risk level in the traditional method, take account of the fuzziness and uncertaintyin risk assessment and prove that the method has certain scientific nature. This paper analyzes the influenced relationship between the factors in shieldconstruction deeply, establishes a risk assessment model based on the entropy weightmethod and the cloud theory, also, combined with the engineering case analysis andverification, provides the reference for the risk management in subway construction.