Research On Risk Evaluation System And Construction Risk Evaluation Of Shield Tunnel In Cobble Stratum

There exsits many uncertainty in the underground project compaired with the projects on the ground.With the high speed of urbanization,the development and utilization of underground space is becoming more and more urgent,underground project is also more and more complex.Although the use of shield machine as the representative of the underground automatic construction machinery has became popular,most projects still face greate risk.The thesis focus on the construction risk in the shield method sub metro construction.With the combination of the risk management theory and the characteristics of construction in cobble stratum,the paper studied the risk identification,risk evaluation method,etc.Firstly,based on several risk indentify method,a risk index system for sub metro shield project in cobble stratum is established.Then,by introducing the Triangular Fuzzy Number theory into the traditional Analytic Hierarchy Process(AHP),an improved AHP model is developed which could overcome the shortage of the traditional AHP model.This study integrates the Fuzzy Comprehensive Evaluation with improved analytic hierarchy progress,and this method suits the metro shield construction risk evaluation and can enhance the applicability and accuracy of the project risk evaluation.Finally,the valibility of the new method has been examined based on actual project,this study give the risk index system,and uses the improved AHP model evaluates the risk,the result shows the different risk level of risk factors in each class and the risk the whole project faces,which verify the accuracy and applicability of the evaluation model.The research on the risk evaluation of shield method sub metro construction in cobble stratum shows that the evaluation model could predicted and solve some problem in construction and could give guidance for the construction safety.