Structural Vulnerability Analysis of Shield Tunnel under Fault Dislocation
In order to study the failure probability model of shield tunnel lining caused by active fault dislocation,considering the effects of fault properties,tunnel geometry and the position relationship between fault and tunnel on mechanical response of cross-fault shield tunnel,the deformation of circumferential joint and the convergence deformation rate of segment diameter are taken as structural performance indexes.Through a series of quasi-static numerical analysis and data regression analysis of cross-fault tunnel,the relationship between the performance indexes of shield tunnel and permanent ground deformation is obtained.The structural vulnerability analysis process of cross-fault shield tunnel is proposed,the exceeding probability of different performance levels are evaluated,and the comparative analysis with existing test vulnerability and empirical vulnerability curves are conducted.Results show that:1)The positional relationship between the tunnel and the fault and the deformation modulus of the stratum where the tunnel is located have a great influence on the deformation and failure degree of the cross-fault shield tunnel.Among them,the shield tunnel is prone to deformation and failure under the condition of crossing the fault,followed by the hard soil condition of overpassing the fault,and the shield tunnel has the strongest ability to resist fault dislocation in the soft soil condition of overpassing the fault.2)According to the failure characteristics of cross-fault shield tunnel,it is suggested that the deformation of circumferential joint be taken as the main performance index in the study of structural fragility.The research results can provide theoretical guidance for the disaster evaluation and disaster mitigation technique of shield tunnels across active faults.
shield tunnelfault dislocationperformance levelvulnerability analysisfailure probability
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