Experimental study on swelling characteristics of compacted bentonite

Compacted bentonites are attracting greater attention as back-filling (buffer) materials for repositories of high-level nuclear waste. Various laboratory tests on the swelling deformation and swelling pressure of compacted bentonites were performed, and the following conclusions were drawn. (1) The curve of swelling deformation versus time is strongly dependent on the initial dry density, vertical pressure, and initial water content. (2) The maximum swelling pressure increases exponentially with increasing initial dry density, whereas the maximum swelling pressure is almost independent of initial water content. (3) The swelling mechanism of compacted bentonite was considered on the basis of the swelling behaviour of swelling clay particles such as montmorillonite. -from Authors