It is of great significance to study the material properties of cemented waste rock backfill (CWRB) for preventing mining damages, solving environmental problems and ensuring engineering security. Consequently, this paper carried out the comprehensively factorial tests to investigate the effects of the confining pressure, dosage of cementitious material and particle size distribution (PSD) of aggregate particles on the strength and ultrasonic properties of CWRB, for which the PSD of aggregate particles obeyed Talbot gradation theory. The results show that the relations between the confining pressure and dosage of cementitious material and the compressive strength and ultrasonic pulse velocity (UPV) of CWRB present the positively linear functions. However, the relations between the PSD of aggregate particles and the UPV, compressive strength, cohesive force and internal friction angle of CWRB perform the quadratic functions. It is considered that there is an optimal PSD of aggregate particles in the CWRB for characterizing its optimum material properties, and using the gradation Talbot index for describing that optimal PSD is between 0.4 and 0.6. The microstructure characteristics show that the CWRB with finer PSD of aggregate particles produces more distributions of microvoids and microcracks, while the CWRB with coarser PSD of aggregate particles contains coarser microvoids and microcracks that cannot be completely filled by hydration products and secondary hydration products. However, the dense hydration products can be formed among the particles in the CWRB with a suitable PSD of aggregate particles to reduce these defects. Its mechanism is considered that the superior PSD of aggregate particles can improve the microstructure of CWRB including the scale and distribution of defects, thereby resulting in the improvements of its strength and ultrasonic properties.

研究水泥废石回填（CWRB）的材料特性对于防止采矿破坏，解决环境问题和确保工程安全具有重要意义。因此，本文进行了全面的阶乘试验，以研究密闭压力，胶凝材料的用量和骨料颗粒的粒径分布（PSD）对CWRB强度和超声性能的影响，为此，骨料颗粒的PSD服从Talbot分级理论。结果表明，胶结材料的围压和用量与CWRB的抗压强度和超声脉冲速度（UPV）之间呈正线性关系。但是，骨料颗粒的PSD与UPV，抗压强度，CWRB的内聚力和内摩擦角执行二次函数。认为在CWRB中存在聚集颗粒的最佳PSD，以表征其最佳材料性能，并使用灰度Talbot指数来描述最佳PSD在0.4到0.6之间。微观结构特征表明，骨料颗粒PSD较细的CWRB产生更多的微孔和微裂纹分布，而骨料颗粒PSD较粗的CWRB含有较粗的微孔和微裂纹，无法被水合产物和二次水合产物完全填充。但是，可以在CWRB中的颗粒之间形成致密的水合产物，并通过适当的聚集颗粒PSD来减少这些缺陷。