Force Equilibrium–Based Model for Predicting Stresses in Soil-Bentonite Cutoff Walls

Abstract

Hydraulic conductivity of soil-bentonite (SB) slurry-trench cutoff walls is highly influenced by the stress state. A model based on force equilibrium is proposed to predict the stresses in SB cutoff walls, considering not only the arching and lateral squeezing effects but also the interaction between SB backfill and surrounding soil by assuming a sliding wedge under limit equilibrium conditions based on Coulomb’s theory. This model is applied to a well-documented SB cutoff wall case, and good agreements are found between the predicted horizontal effective stress and those evaluated from cone penetration test data. The decrease in stresses within the deep portion of SB cutoff walls is successfully simulated. A parametric study shows the horizontal effective stress is sensitive to the properties of the surrounding soil, but insensitive to those of the backfill. General estimation of horizontal stress can be made in practice according to the geometry similarity in stress profiles.