中文摘要：

砂-膨润土混合物已被很多核能国家选为核废物地质处置库中理想的缓冲/回填材料。膨润土中加入砂可提高热传导系数和强度,维持适当的膨胀力,使其工程上易于处理并节省成本;但同时会导致其阻水能力和自愈性减弱。研究表明,影响砂-膨润土混合物以上各性质的主要因素为：砂/膨润土配合比、初始含水量、干密度等,它们综合决定着砂/膨润土最优配合比的选取。石英砂对混合物的渗透性、热传导性、强度等的影响,最优配合比选取,以及非饱和状态下吸力变化对混合物渗透性的影响等,应该是今后一段时间内砂-膨润土混合物研究的重点。

英文摘要：

Compacted sand-bentonite mixtures are considered in many countries as buffer/ backfilling materials for geological disposal of high-level radioactive wastes.On one hand,the addition of sand can improve the thermal conductivity and strength to the buffer/ backfilling materials,It also limits excessive swelling pressure.Moreover,the presence of sand makes the material easy to handle and more economic.On the other hand,the sand makes the self-sealing behaviours and water-resistance performances lower than those of the pure bentonite at the same dry density.Because the ratio of bentonite to sand,dry density and initial water content of the material are the main factors affecting the behaviour of sand-bentonite mixture,and the optimum percentage of added sand is determined by the integration of these factors,Therefore,The future research on sand-bentonite mixture should focus on the influence of sand properties of hydraulic conductivity,thermal conductivity and mechanical properties,the selection of optimam percentage of added sand and the influence of unsaturated characteristic on hydraulic conductivity.