A resilience optimization design model considering surcharge for large diameter shield tunnel

Abstract

Large-diameter shield tunnels face challenges owing to the complex strata and surcharges. The robustness of ground disturbance during excavation and resilience during operation in the design model must be considered. This involves establishing a damage evolution law for existing shield tunnels after surcharging and proposing a resilience design method for the entire cycle. In this study, the design process was initiated by utilizing existing borehole survey information and incorporating stratum uncertainty. Subsequently, a ground surcharge was applied to evaluate the changes in the force and deformation at different design points after surcharging. A resilience assessment was conducted in accordance with the specified criteria, and the results indicated that a majority of the design points exhibited robustness within acceptable limits after the surcharge. The original excavation design demonstrated satisfactory initial performance in terms of robustness. However, the resilience after surcharging was suboptimal, exhibiting a value of only 0.65. To enhance the resilience, the design must modify the reinforcing rate to achieve a higher resilience state of 0.8. By considering both the robustness of the design and its resilience after surcharging, modifications can be made to align the design with real operational conditions, which may help improve the overall resilience.