Stochastic analysis of dual tunnels in spatially random soil

The undrained stability of dual circular tunnels buried in spatially random soils is investigated by imposing the random adaptive finite element limit analysis (RAFELA). The emphasis is on quantifying the effect of influential factors including the geometry parameters and spatially variability parameters on the bearing capacity and failure probability of tunnels by assuming a lognormal distribution on undrained shear strength within a spatial correlation structure. Predictions were obtained by the scope enclosed by upper bound (UB) and lower bound results (LB) results within 5% relative errors. To account for a combined effect simultaneously caused by depths of tunnels, spaces between tunnels, soil weights, and spatially variability parameters on the stability of tunnels, all independent variables are involved in parametric studies in pairs. Results revealed several failure patterns and announced how the stability evolves with changes in tunnel geometry and soil spatial variability.

Automated summary

The undrained stability of dual circular tunnels buried in spatially random soils was analyzed using the random adaptive finite element limit analysis (RAFELA). The study focused on quantifying the influence of geometry parameters and spatial variability parameters on the bearing capacity and failure probability of tunnels, based on a lognormal distribution of undrained shear strength within a spatial correlation structure. The results revealed various failure patterns and showed how tunnel stability evolves with changes in tunnel geometry and soil spatial variability.