块石形状对土石混合体力学行为影响的颗粒流模拟

Particle flow simulation for effects of rock block shape on mechanical behavior of soil-rock mixture

考虑块石形状为球体、正方体和长方体三种情况,通过正方体与球体相比较来探究块石棱角度不同对土石混合体力学特性的影响,通过长方体与正方体相比较来探究块石球度不同对土石混合体力学特性的影响。首先,提出特定形状块石三维离散元精细建模的方法;接着建立含石量为30%和80%的块石形状分别为球体、正方体和长方体的土石混合体三维颗粒流数值模型;然后,对土石混合体大三轴试验进行颗粒流模拟,获得了不同含石量及不同块石形状的土石混合体试样的宏观力学特征;最后,详细分析了块石形状对土石混合体力学行为影响的细观机理。结果表明,块石形状会影响土石混合体的力学行为,其影响的程度与含石量密切相关;配位数、块石颗粒平均旋转量和摩擦功的演化规律能够很好地从细观水平上反映块石形状的作用机理。

In order to explore the meso-mechanisms of effects of rock block shape on mechanical behavior of soil-rock mixture（SRM）,spherical,cubic and cuboid-shaped rock blocks are taken into consideration.SRM with cubic rock blocks are compared with that of spherical rock blocks to explore the effects of block angularity.SRM with cuboid-shaped rock blocks are compared with that of cubic rock blocks to explore the effects of block sphericity.Firstly,a 3DDEM refined modeling method for specific rock block shape was developed.Then,particle flow numerical models of SRM with 30% and 80% rock block proportion（RBP）were established,whose block shape is spherical,cubic and cuboid-shaped respectively.Then,particle flow simulation for large scale triaxial tests of SRM was conducted to obtain strength and deformation characteristics of SRM with different rock block shape and RBP.Finally,meso-mechanisms of effects of rock block shape on mechanical behavior of SRM were intensively analyzed.The results show that rock block shape affect the mechanical behavior of SRM and the degree of influence are closely related to RBP.The evolution of coordination number,mean rotation of rock blocks and frictional work can well reflect the meso-mechanisms of effects of rock block shape.