高压实高庙子膨润土GMZ01的膨胀力特征

 高放废物深地质处置中，缓冲/回填材料系统起着工程屏障、水力学屏障、化学屏障、传导和散失放射性废物衰变热等重要作用，是高放废物地质处置库长期安全性和稳定性的有效保障。前人研究表明，膨润土是理想的缓冲/回填材料。在归纳总结压实膨润土膨胀力的室内试验研究成果的基础上，采用恒体积试验法研究高压实高庙子膨润土GMZ01的膨胀力特性，该膨润土已经被确定为我国高放废物地质处置库首选缓冲材料。结果表明，高压实高庙子膨润土GMZ01膨胀力随时间的变化曲线是一条渐近线，而时间/膨胀力与时间之间存在很好的线性关系；膨胀力发展过程曲线与吸水量曲线具有明显的阶段性特征；高压实高庙子膨润土的膨胀力和干密度之间存在指数关系，干密度是影响膨胀力的一项重要的因素。所取得的膨胀力特性成果，对于高庙子膨润土膨胀性能的正确判定具有非常重要的意义。

CHARACTERISTICS OF SWELLING PRESSURE OF DENSELY COMPACTED GAOMIAOZI BENTONITE GMZ01

In the deep geological disposal of high-level radioactive waste，buffer/backfill materials act as engineering barrier，hydraulic barrier，and chemical barrier，which can transmit and propagate the heat generated by radioactive waste in the deep geological repository. Results show that bentonite is a kind of ideal buffer/backfill material. Based on a brief review of the laboratory testing techniques for the measurement of swelling pressure of expansive clay，the characteristics of swelling pressure of Gaomiaozi bentonite(GMZ01)，which has been chosen as the first choice for using as buffer/backfill materials in deep disposal of high-level radioactive waste in China，have been studied by the constant volume test method. Results show that swelling pressure changes with time nonlinearly，but there is a linear relationship between time/swelling pressure and time. Curves of swelling pressure and the amount of absorbed water varying with time can be easily classified into several typical phases. For the Gaomiaozi bentonite tested here，there is an exponential relationship between swelling pressure and dry density；and dry density is an important factor influencing swelling pressure. All results obtained here are very important for the study of expansive properties of Gaomiaozi bentonite.