为研究不同颗粒级配陷落柱充填物在不同固结荷载下的力学特性，基于土工固结试验制备不同状态下的相似模拟充填体试样，通过充填体在不同状态下的三轴加载实验、压汞及扫描电镜实验，研究了陷落柱充填体三轴应力状态下的力学特征及微观结构演化机制。结果表明：充填体具有明显的塑形特征，其应力−应变曲线可以划分为4个阶段：孔隙压密段、稳定变形段、变形破坏段和类蠕变阶段。充填体偏应力随Talbol指数n呈先增加后减小的趋势，充填体三轴抗压强度与Talbol指数之间符合二次多项式关系，均满足较高的拟合度并且偏应力强度达到最优的Talbol指数分别为0.71、0.65和0.64；偏应力随着固结荷载的增加而线性增加，增长率随着固结荷载和Talbol指数的增加呈逐渐减小的趋势。结合压汞和扫描电镜测试结果，固结荷载和Talbol指数的变化改变了颗粒间的接触状态，影响着岩土体试样的偏应力强度；随着Talbol指数的增加，充填体内颗粒间的相互作用增强，初始承受的外荷载比例增大，骨架结构效应更加显著，偏应力则主要来自岩土颗粒的接触应力集中。通过力学强度和微观结构特征研究在宏观和微观尺度上解释了充填体的颗粒级配效应提供参考。

In order to study the mechanical properties of collapse column fill under different consolidation pressures and grain compositions. Base on similar simulated rock-soil mass sample under different states of geotechinal consolidation test preparing, we investigated the mechanical characteristics and microstructure evolution mechanism of collapse column filling by conducting the triaxial loading test, mercury intrusion porosimetry and scanning electron microscopy in different states of rock-soil mass. The results show that the rock-soil mass has obvious shaping characteristics and the stress-strain curve can be divided into four stages: pore compaction stage, stable deformation stage, deformation failure stage and creep-like stage. The compressive strength of rock-soil mass increases first and then decreases with Talbol index n. Besides, the triaxial compressive strength and Talbol index of rock-soil mass were fitted with the quadratic polynomial, with higher degree of fitting, and the Talbol index corresponding to the optimal compressive strength is 0.71, 0.65 and 0.64 respectively. Generally, the compressive strength increases linearly with the increase of consolidation pressure, while the growth rate decreases with the increase of consolidation pressure and Talbol index. According to the results of mercury intrusion porosimetry and scanning electron microscopy, it is indicated that the change of consolidation pressure and Talbol index changes the contact state between particles, which in turn affects the compressive strength of rock-soil mass specimens. With the increase of Talbol index, the interaction between particles in rock-soil mass is enhanced, the proportion of initial external load increases, the skeleton structure effect is more significant, and the compressive strength mainly comes from the contact stress concentration of rock-soil mass particles. To sum up, the mechanical test and microstructure characteristics study of rock-soil mass provide a reference for the effect of particle gradation from the macro-scale and micro-scale.