SUCTION AND WATER UPTAKE IN UNSATURATED COMPACTED BENTONITE

摘要

Suction is an important process dominating water movement in unsaturated compacted bentonite. Suction measurements were carried out to investigate the characteristics of suction with respect to key disposal conditions. The suction values decreased with increasing the water content at a given dry density, and they increased with increasing the dry density. The suction variation with an increase of temperature was negligible for the water content up to 17%, while there was a little lower value of suction at the water content of 22% when the temperature was 70℃. For the dry density of 1,600 kg/m3, the suction value in the vertical measurement is a little lower than that in the horizontal one due to the microstructural anisotropy of compacted bentonite. The modeling of water uptake in unsaturated compacted bentonite is allowed to predict the re-saturation and to analyze the thermal-hydromechanical behavior for the buffer of a HLw repository. To this end, water uptake tests were conducted to compare their results with those calculated using the coupled hydro-mechanical model of a computer code ABAQUS. Both results were in reasonably good agreement with each other, which suggested that the code could be used to analyze the water uptake of compacted bentonite for the buffer of the KRS.