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通过对土石粒径界限、块石分布规律与粒径分布频度的研究,基于直接生成法建立了土石混合体的三维随机模型,形成了一套较为完整的、操作性强的三维随机模型构建方法。在此基础上,将三维随机模型构建方法与FLAC~(3D)随机建模方法相结合,建立与真实土石混合体具有相同统计规律的有限差分模型,开展室内直剪数值仿真试验研究,获取了不同垂直压力下的剪应力-位移曲线和相应的剪切带分布,探讨了土石混合体的剪切破坏特性与土石相互作用机制。剪切过程中由于土体产生的不同程度的剪切变形以及块石在摩擦作用下发生的水平或旋转运动,导致土石混合体的剪切带表现出明显的不规则和不连续特点,其剪应力-位移曲线具有应变硬化特点。研究表明,三维随机模型能够反映土石混合体的宏观力学性质和细观破坏机制,可作为力学性质研究的有效载体。
Based on the research on the limit of the rock size, the distribution rule of rock mass and the frequency of particle size distribution, a three-dimensional stochastic model of soil-rock mixture was established based on the direct generation method, which formed a set of complete and operable three-dimensional stochastic model method. On this basis, combining the method of three-dimensional stochastic modeling and the stochastic modeling method of FLAC 3D, a finite difference model with the same statistical law as that of the real soil-rock mixture is established, and the numerical simulation experiment of indoor direct shear is carried out. The shear stress-displacement curves under different vertical pressures and the distribution of the corresponding shear zones, the shear failure characteristics of soil-rock mixture and the interaction mechanism between soil and rock are discussed. The shear deformation of soil-rock mixture due to the different degrees of shear deformation caused by soil and the horizontal or rotational movement of rock mass caused by friction during shearing process leads to obvious irregular and discontinuous characteristics of shear band of soil-rock mixture. Stress-displacement curve has the characteristics of strain hardening. The research shows that the three-dimensional stochastic model can reflect the macroscopic mechanical properties and the mechanism of meso-damage of soil-rock mixture, and can be used as an effective carrier for the study of mechanical properties.