Reliability Analysis and Design for Tunnel Face Stability in Spatially Random Soils

Traditional deterministic analyses of tunnel face stability often neglect the uncertainties of geotechnical parameters, while simplified reliability analyses fail to account for soil spatial variability. To overcome these limitations, this study proposes an efficient framework for the reliability analysis and design of tunnel face stability. A probabilistic framework is proposed by coupling the stochastic limit analysis model with the improved Hasofer-Lind-Rackwits-Fiessler recursive algorithm (iHLRF)/inverse iHLRF algorithm. The proposed method allows for rapid and precise reliability analysis and design of tunnel face stability while considering soil spatial variability. An example of tunneling in frictional soils is used to demonstrate the feasibility and efficacy of the proposed method. The results show that the proposed method successfully assesses the reliability of tunnel face stability and carries out a reliability-based design (RBD) of support pressure in the presence of soil spatial variability. The results also demonstrate the feasibility of using the forward and/or inverse first-order reliability method (FORM) in high-dimensional problems.