高放废物处置库预选缓冲/回填材料液塑限测定试验研究

Study on Liquid and Plastic Limit Test of Buffer/Backfill Material for HLW Disposal in China

深地质处置被国际上公认为处置高放废物的最有效可行的办法。缓冲/回填材料是高放废物深地质处置中非常重要的一道人工屏障。经过筛选,内蒙古高庙子钠基膨润土被确定为我国高放废物深地质处置的首选基料。通过对该钠基膨润土的落锥式和碟振动式两种液塑限测定方法的比较,确定利用碟振动式仪法测试更合理,测得液限为310%,塑限值为39.0%,塑性指数为271.0%。结果表明,内蒙古高庙子钠基膨润土具有高的水容量、荷重下的高致密性、低渗透性、较高的强度和较强的水稳定性。

The deep geological disposal is regarded as the most reasonable and effective way to safely dispose high-level radioactive waste （HLW） in the world, Buffer material layer is one of the important engineering barriers in the HLW geological repository. Gaomiaozi （GMZ） bentonite in Inner Mongolia has been selected as the potential materials of the buffer/backfill material for China＇s HLW repository. As one of the key chemical-physical parameters, liquid and plastic limits of GMZ Na bentonite have been tested by both fall-cone method and percussion method in this study. Systematic experiments indicated that percussion method is more reasonable for high montmorillinite content bentonite. The test results show that the liquid and plastic limit of GMZ Na bentonite are of 310% and 39.0% respectively with the plastic index 271.0%. Which indicates that GMZ Na bentonite is characterized by high water capacity, high compactness under weight, low permeability, higher intensity and well aqueous stability.