Reliability-based approach for the stability analysis of shallow circular tunnels driven by a pressurized shield

International audienceA probabilistic analysis of the stability of a shallow circular tunnel driven by a pressurized shield in a frictional and cohesive soil is presented. A deterministic model based on numerical simulations is used. The response surface methodology is employed for the assessment of the Hasofer-Lind reliability index. Only the soil shear strength parameters are considered as random variables. The assumption of uncorrelated variables was found conservative in comparison to the one of negatively correlated parameters. Also, it was found that the hypothesis of nonnormal distribution for the random variables has almost no effect on the reliability index for the practical range of values of the applied pressure