Mixture of high-density bentonite pellets are considered as a potential buffer/backfill material for high-level radioactive wastes (HLW) repository. One of the outstanding problems of this material is the particle segregation induced by vibration during transportation and emplacement. In this work, the vibration-induced segregation behavior of crushed GMZ (Gaomiaozi) bentonite pellet mixtures with different size distributions was experimentally investigated using a cylindrical container under vertical vibrations. The degree of segregation was evaluated by a weighted coefficient of variation (WCV) reflecting the changes in particle size distribution before and after vibration. Results show that generally the WCV increases with decreases of particle size ratio, the mass fraction of the fine size class and the number of size classes of the mixture. The influences of particle size ratio and distribution were interpreted by two dominant mechanisms including percolation and convection, and could be incorporated into a particle characteristic index (PCI). Further analysis shows that the WCV monotonously increases with the increase of PCI and the relationship between them can be well described using a sigmoid function. Finally, based on the analyses of the experimental results, strategies for reducing segregation were proposed.

高密度膨润土颗粒的混合物被认为是高放废物（HLW）储存库的潜在缓冲/回填材料。这种材料的突出问题之一是在运输和安置过程中由振动引起的颗粒偏析。在这项工作中，使用圆柱形容器在垂直振动下，通过实验研究了粉碎的具有不同尺寸分布的GMZ（高庙子）膨润土颗粒混合物的振动诱发的偏析行为。通过反映振动前后的粒度分布变化的加权变异系数（WCV）评估偏析程度。结果表明，一般而言，WCV随着粒度比，细粒度级的质量分数和混合物粒度级数的减少而增加。粒径比和分布的影响可以通过渗透和对流这两个主要机理来解释，可以纳入颗粒特征指数（PCI）。进一步的分析表明，WCV随着PCI的增加而单调增加，并且它们之间的关系可以使用S形函数很好地描述。最后，在对实验结果进行分析的基础上，提出了减少偏析的策略。