Abstract:

This paper presents test results carried out on heavily compact sand-bentonite mixtures. To measure suction of the mixture in a larger range of water content, a pressure plate apparatus and filter papers are used. The obtained soil-water characteristic curves shows that the results obtained from the two methods are consistent. The residual water content and water entry value are determined from the measured curve. By using a suctioncontrollable oedometer for unsaturated soil, a series of one-dimensional compression tests were performed on unsaturated compacted sand-bentonite mixtures with different constant suctions. The test results indicate that the yield stress increases and compression index decreases with increase of the imposed suction.

Key words: sand-bentonite mixtures; buffer/backfill material; soil-water characteristic curve; compression curves