Risk Comprehensive Assessment of Shield Tunnel Construction Based on Cloud Theory

The traditional risk assessment method can not associate the fuzziness with the randomness of risk. Therefore, on the basis of cloud theory, the study puts forward a comprehensive risk assessment model for shield tunnel aiming at the fuzziness and randomness of the risk assessment index of shield tunnel construction. Firstly, construct the evaluation index system which can reflect the construction risk of shield tunnel. Then, convert the experts' language value on each evaluation index into the weight of the cloud to characterize the importance of each evaluation index. The weight and linguistic evaluation of the index are discussed by the panel, and the cloud model is obtained which can reflect the fuzziness and randomness of the risk state of shield tunnel construction. Finally, use the method of cloud theory to evaluate the risk level of shield tunnel. The model is successfully applied to the construction risk assessment of the Shiziyang shield tunnel which verifies the effectiveness and practicability.