Interactions between PVC Geomembranes and Compacted Clays

TLDR

Using a direct shear device on as‑compacted plastic soils, the study examined PVC geomembranes with smooth or textured surfaces across plasticity indices of 35–100 %, expressing peak and residual failure envelopes via Coulomb criteria. Adhesion and angle of friction rose with plasticity index up to 70 % before declining, with peak‑strength adhesion exceeding residual adhesion while the opposite held for friction angle, indicating adhesion is a more relevant metric, and smooth versus textured geomembranes differed little at residual state.

Abstract

The interactions between plastic soils and polyvinyl chloride (PVC) geomembranes were studied using a direct shear device under as-compacted conditions. The PVC geomembranes had smooth or textured surfaces, and the soils were of plasticity index (PI) ranging from 35 to 100%. The peak and residual failure envelopes were expressed using Coulomb failure criteria. The adhesion and angle of friction increased for PIs up to 70% and subsequently recorded a decrease. The adhesion is larger for the peak strength compared to the residual strength, but it was the reverse for the angle of friction. The efficiency in terms of adhesion appeared more relevant than that of the angle of friction in expressing the interactions between geomembrane and cohesive soils. The smooth and textured geomembranes showed little difference in results at the residual state.