Upper bound stability analysis of slurry-supported trenches in layered soils

Abstract

Abstract A stability analysis of slurry-supported trenches in horizontally layered cohesive-frictional soils by using the kinematical approach of limit analysis is presented. To ensure the kinematical admissibility, the failure surface in the formulated multi-block rotational mechanism was composed of several segments of logarithmic spirals with a same rotation center. To account for varying soil properties among different layers, both toe and above-toe failure patterns were considered. The associated factor of safety was determined by the shear strength reduction technique and was verified by comparison with the shear strength reduction finite element method (SSRFEM). It was found that the results obtained from the simplified approach by using weighted average soil parameters were not reliable and sometimes led to significantly overestimated safety factors on trench stability in layered soils, which deserves more attention in practice.