Analysis of the Volume Change Behavior of Expansive Compacted Soils

摘要

Compacted mixtures of sand-bentonite (commonly named Bentonite Enhanced Sand, BES) are widely used to control the movement or migration of hazardous substances from the disposal site to the surrounding environment. Barriers built with those materials exhibit high strength and low compressibility with a very low permeability. Those characteristics can be reached by using mixtures with enough sand (to ensure good stability of the compacted mixture) and bentonite (to fill the voids between the sand particles). This paper shows the results of an experimental study of the volumetric behavior of compacted mixtures of sand-bentonite following wetting under constant vertical stress. The influence of initial compaction conditions, the applied vertical stress and the bentonite content were studied. The experimental program included a series of odometer tests performed with samples compacted at different densities and water contents. The results indicate that the development of swelling deformations with time is highly dependent on the compaction conditions of the BES and the confining stress.