Three-dimensional global and local stability analysis of slurry trenches in spatially variable soils

Currently, the collapse mode of slurry trenches considering soil spatial variation has not been well investigated. To address this problem, random field theory is used to describe the spatial variability of the soil mass of the slurry trench, and a three-dimensional discrete failure mechanism for global and local collapse of the slurry trench is constructed using a spatial Discretisation technique. By introducing randomly distributed cohesion and friction angle into the construction of the failure mechanism, the upper bound solution for the safety factor of the slurry trench is obtained within the framework of limit analysis theory. Combining the SPCE and Monte Carlo method, the failure probability and the probability density function for global and local collapse of the slurry trench are calculated. The parameter analysis revealed that the failure probability of the slurry trench increases with increasing cohesion variance, vertical autocorrelation distance, horizontal autocorrelation distance, and positive correlation coefficient between cohesion and friction angle, while it decreases with increasing negative correlation coefficient between cohesion and friction angle. The safety factors of the slurry trench derived from the theoretical calculation are compared with the results obtained from numerical simulations. The comparing results indicate that the failure probability analysis method for slurry trenches in spatially variable strata based on random field theory is effective.