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

Abstract

This paper uses limit analysis to develop a two dimension (2D) and three dimension (3D) analysis of slurry trench local and overall stability for cohesive soil. Formulas for the slurry trench stability analysis are obtained through theoretical derivation with the basis of limit analysis theory, and then rotational mechanisms are presented for slurry trench stability. For 2D slurry trench local and overall stability, the failure surfaces have the shape of circular arc, while it has the shape of spherical cap for 3D local stability, and it has the shape of torus with outline defined by circle for 3D overall stability. Examples are provided to illustrate the safety factor influence by 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 are around 1.1 times larger than the safety factor of the 2D solutions for local stability, however 1.2 times (B/h=1) for overall sta...