Closed-Form Solution for Stability of Slurry Trenches

Abstract

This paper presents a variational limit equilibrium closed-form solution for the stability of slurry-supported trenches in cohesive soil, frictional cohesive soil, and cohesionless soil. Study results indicate that the critical slip-surface geometry is either planar or log spiral. The normal stress distribution, which indicates the likely depth of a tension crack at the crest over the slip surface, was also obtained as part of the complete solution and as a function of groundwater-table level. The closed-form solution was used to produce stability charts for a practical range of parameters. The charts can be used to conveniently assess the stability of a given slurry trench for preliminary design. The paper gives two different examples for trenches to illustrate the influence of the slurry level on the trench stability. To introduce the analytical solution, this study is limited to a simple slurry trench problem; however, extension of the present framework to deal with complex problems would be straightforward.