Influence Factors of Swelling Characteristics of GMZ Bentonite

The swelling characteristics of bentonite is important to evaluate the long-term performance of deep geological repository of nuclear waste. A series of wetting tests on GMZ sodium and calcium bentonite were performed to investigate the swelling characteristics under different conditions. The influences of initial dry density and particle size were studied at different temperature. The test results show that the swelling deformation due to wetting is mainly affected by the dry density and little affected by particle size. The swelling ratio of GMZ bentonite increases with the increase of initial dry density. However, only the swelling ratio of sodium bentonite increases with the rise of temperature. The process of swelling deformation is a single or multi-stage mode depending on the initial dry density. Finally, the sample of the bentonite is subjected to a rapid swelling with the increase of the initial dry density. The swelling property of sodium bentonite is much higher than that of calcium bentonite. All results are very important for the study of swelling properties of GMZ bentonite.