【摘要】 高放废物缓冲回填工程屏障材料膨润土塑性高,可调性差,加水制样过程中土"团聚化"及含水率分布不均匀现象明显,影响缓冲回填压实砌块质量。与传统直接喷水法对比,试验探索一种加水工艺,即采用粉状冰与膨润土粉混合调配膨润土含水率,试验含水率在5%~30%之间,分析了膨润土与水混合物的混合效率、黏附质量损失率、实际含水率与理论含水率差值、团聚体含水率与粒径关系、混合物中团聚体分布及含量等指标综合评价加水工艺优劣,提出微波辅助解冻法以提高冰-土混合法制备土样的解冻效率。结果显示,与喷水法相比,冰-土混合法混合效率高,膨润土黏附容器少,实际含水率更集中于目标含水率,团聚体数量明显减少,水分分布更均匀;配套的微波辅助解冻法能有效提高冰-土混合法解冻效率,且不影响团聚体数量及试样含水率。研究成果可供我国高放废物缓冲回填材料高效生产及其他高黏性土含水率均匀调配参考。更多还原

【Abstract】 Bentonite is buffer/backfill material needed in high level waste engineering barrier, and the high plasticity of bentonite affects the quality of buffer/backfill block. In a process of adding water for sample preparation, soil agglomeration and uneven distribution of water content affect the quality of blocks. Compared with traditional spray water method, this experiment explored a new water adding technic, mixing ice powder with bentonite powder(shortly the ice-soil mixing method). Water content is controlled between 5%-30%. In order to evaluate the ice-soil mixing method, the mixing efficiency, mass loss rate, the deviation between actual water content and target water content, the relationship between water content and agglomerated particle size, distribution and contents of agglomerate are measured. Besides, microwave-assisted thawing method is proposed to decrease thawing time. The results show that compared with spray water method, the ice-soil mixed method is less time consuming, less causing adhere to the container, and less causing water content deviate to targets. Moreover, the size and percentage of agglomerate in mixture are also decreased obviously; and water content distribution is more homogeneous; furthermore, microwave-assisted thaw method can significantly accelerate the thawing rate without affecting the amount of agglomerates and water content of specimens. This research provides a reference for the production of buffer/backfill material for High Level Waste(HLW) disposal, and can also be referenced by water content adjustment of other cohesive soil.更多还原