Discretization-based kinematic approach for three-dimensional trench stability under slurry support in multilayered ground

Focus of the existing studies on the stability analysis of slurry-supported trenches is primarily placed on uniform soils, despite the fact that soil stratification is often observed in the field. This paper investigates three-dimensional slurry trench stability in layered cohesive-frictional soils by using the kinematic approach of limit analysis. A discretization-based rigid rotational mechanism is formulated to address this issue and rigorous upper bounds on trench safety factor are obtained by adopting the shear strength reduction technique. The proposed method is verified by comparison with the shear strength reduction finite element method (SSRFEM) on the trench safety factor and the corresponding optimal failure profile. Parametric study is carried out to investigate the influence of slurry parameters and surcharge load on trench stability and the results are presented in the form of stability charts for the convenience of practical use. The applicability of the horizontal slice method (HSM) is also discussed in details by comparison with the present study through a classic reported case and a full-scale field test.