Limit Analysis for Local and Overall Stability of a Slurry Trench in Cohesive Soil

This paper uses limit analysis to develop a two-dimensional (2D) and a three-dimensional (3D) analysis of slurry trench local and overall stability for cohesive soil. Formulas for the slurry trench stability analysis are obtained through theoretical derivation based on limit analysis theory, and rotational mechanisms are then presented for slurry trench stability. For 2D slurry trench local and overall stability, the failure surface has the shape of a circular arc, whereas it has the shape of spherical cap for 3D local stability, and it has the shape of a torus with an outline defined by a circle for 3D overall stability. Examples are provided to illustrate the safety factor influenced by the slurry and soil bulk density ratio, slurry level depth and trench depth ratio, thickness of the weak soil layer, cohesion, and trench width and depth ratio. The safety factor for the 3D solutions is approximately 1.1 times greater than the safety factor for the 2D solutions for local stability but 1.2 times greater (B/h=1) for overall stability. This work is made available under the terms of the Creative Commons Attribution 4.0 International license http://creativecommons.org/licenses/by/4.0/.