Stability Analysis of Slurry Trenches in Similar Layered Soils

Abstract

Slurry trenches are often used to impede groundwater flow or to contain soil and groundwater contamination. The stability of the slurry trench during excavation and prior to backfilling is a major concern in design. A horizontal slice method for stability analysis of slurry trenches, which allows consideration of soil stratification, is presented. Vertical force equilibrium for each slice of the sliding mass and horizontal force equilibrium for the whole sliding mass are considered on the basis of limit equilibrium. The factor of safety is obtained via the Newton–Raphson method and the critical slip surface corresponding to the minimum factor of safety is located by the pattern search method. The proposed method is verified via consideration of a previously reported problem. It is then applied to a full-scale field experiment in three-layer soils. The obtained minimum factor of safety and location of the slip surface of the sliding mass are in excellent agreement with the experimental measurements. Analyses of trenches having a weak layer at various depths demonstrate potential variations in slip surface inclination between soil layers.