Effect of water salinity on the hydro-mechanical behaviour of light backfill material

Abstract

A series of one-dimensional compression tests was conducted to examine and compare the hydro-mechanical behaviour of light backfill (LBF) material, composed of 50% bentonite and 50% sand, in the presence of distilled water and 100 g/l CaCl2 and 200 g/l CaCl2 solutions. In addition, the hydro-mechanical parameters of LBF required for compliance modelling of the deep geologic repository (DGR) emplacement room sealing system were determined. The tests were conducted on 50-mm-diameter by 10-mm-thick LBF samples, using standard lever arm consolidation equipment. Several different loading and wetting paths were examined, including allowing the LBF to swell up to 20% vertical strain on distilled water or solution uptake and constraining the LBF from swelling on distilled water or solution uptake.