Study On Fuzzy Comprehensive Evaluation Of Structural Safety Of Highway Tunnel In Meizoseismal Area

The construction of traffic facility in west China will be accelerated due to the West Development Strategy. Many tunnels are to be born in the mountain areas of west China where the potential seismic intensity is extremely high. Studies on theories and methods for safety evaluation of tunnel structures in meizoseismal areas are of great significance because current methods are not so sufficient in China.In this dissertation, based on the case study of Cheyang tunnel, fuzzy comprehensive evaluation system of structural safety of highway tunnel in meizoseismal area is established, combining the fuzzy comprehensive evaluation method and the 3-D numerical simulation. The work can be concluded as two parts:a) Various factors affecting structural safety of tunnels in meizoseismal areas are identified and evaluating indicators are obtained comprehensively reflecting the safety condition of tunnels due to previous researches home and abroad, national regulations and standards and principles of indicator selection. Second level fuzzy comprehensive evaluation model is proposed based on fuzzy comprehensive evaluation theory and step analysis method and the power of each indicator is obtained. The four-level standard for evaluating structural safety of highway tunnels in meizoseismal areas is proposed and the comment collection is established based on the seismic damage investigation report of the tunnels on Duwen highway. The membership function of each indicator is identified and the fuzzy indicators in the factor set are specified.b) The established fuzzy comprehensive evaluation system is applied to evaluate the structural safety of section K195+780-K195+870 and K195+950-K196+150 of Cheyang tunnel. The software for evaluating structural safety of highway tunnel in meizoseismal areas is developed. The 3-D numerical simulation is performed to analyze the seismic response of the tunnel and the safety of the lining structure is evaluated. According to the comparative study of the two methods, the fuzzy comprehensive evaluation system for evaluating structural safety of highway tunnel in meizoseismal area proves to be correct and applicable.