摘要：This laboratory experimental program investigated the impact of variations in the expansive mineral content, the grain size distribution of employed bentonite, the initial dry density and the selected hydration path on the water retention characteristics and swelling properties of processed Callovo-Oxfordian claystone and its mixtures with MX80 bentonite. The French reference concept for the disposal of nuclear waste in deep sedimentary rock formations envisages the reemployment of excavated material as backfill material, which is installed in situ by means of conventional compaction techniques. The investigations were of special interest as the major issues involving in situ compacted backfill materials were portrayed. Experiments showed that the impact of variations in the dry density on the water retention characteristics of all materials vanished as suctions exceeded 100 MPa. The negligible impact of variations in the initial dry density on the collapse behavior of claystone/ bentonite mixtures remained questionable.
