Robust design of shield tunnels -- considering the longitudinal variation of input parameters

摘要

This dissertation, aimed at developing an improved design methodology for shield tunnels that explicitly considers design robustness against longitudinal variation of input parameters (such as soil parameters). To this end, a new solution model for shield tunnel performance analysis was first developed. In this new model, the random field concept was employed to model the longitudinal variation of input parameters. The input parameters (in the longitudinal domain) that had been generated with Monte Carlo simulation (MCS) were used as inputs for the tunnel longitudinal behavior analysis. Here, the finite element method (FEM) based upon Winkler elastic foundation theory was employed. The analyzed tunnel longitudinal responses as well as the input parameters that had been generated with MCS were then used to study the performance (i.e., structure safety and serviceability) of tunnel segment rings. For the latter analysis, the force method was used. Finally, the robust design concept was integrated into the design of shield tunnels to guard against variation of tunnel performance caused by longitudinal variation of input parameters. Within the framework of robust design, a multi-objective optimization was performed aiming to optimize the design with respect to design robustness against longitudinal variation of input parameters and cost efficiency, while satisfying safety and serviceability requirements. Through illustrative examples, the effectiveness and significance of improved shield tunnel design methodology was demonstrated.