The Drained Strength of Bentonite Enhanced Sand

INTRODUCTION

Barriers with a low hydraulic conductivity are used as part of waste containment systems to prevent groundwater contamination by liquids from the waste. Commonly barriers are either a geomembrane (usually an HDPE sheet), a mineral layer or a combination of the two. Recently there has been increasing interest in the use of bentonite±sand mixtures as the mineral layer, in both land®ll liners and vertical cut-off walls, partly because they are less susceptible to frost damage and desiccation cracking than compacted clay (Dixon et al., 1985; Kraus et al., 1997). Currently there is uncertainty about the strength and bearing capacity of these materials. This note reports drained strength data for bentonite±sand mixtures and proposes that trends in these data are mainly the result of variations in the relative density of the sand.