为了更加真实地模拟土石混合体的物理力学特性,提出了一种基于不规则块石球度和凹凸度的随机几何模型生成技术,并建立了相应的块石三维离散元模型。然后采用无底圆筒堆积试验对球度和凹凸度这2个块石几何模型控制参数进行了数值验证。最后建立了符合宏观统计规律的土石混合体三维离散元随机模型,对土石混合体大三轴试验进行颗粒流模拟,并与室内试验结果进行对比分析。结果表明:所提出的不规则块石几何模型随机生成方法简单实用,几何模型控制参数合理有效;通过选取合适的颗粒细观参数,建立基于随机不规则块石体的土石混合体数值模型,能很好地模拟土石混合体的物理力学性质,包括颗粒之间的细观接触特征、土石混合体的应力-应变关系特征等,为进一步研究土石混合体的变形破坏机理提供了一条有效的途径。
Abstract
In order to simulate the physic-mechanical properties of soil-rock mixture (SRM) realistically, a technique based on sphericity and angularity to constructing random geometric and discrete element method (DEM) model of irregularly shaped (IRS) rock block is proposed. Then particle flow simulations for open bottom cylinder tests of IRS rock blocks under different sphericity and angularity parameters are conducted. Finally, three dimensional (3-D) stochastic models of SRM which conform to the macroscopic statistical rule are established and DEM numerical simulations of large scale triaxial test are conducted. The numerical results and laboratory results are compared and analyzed. It is noteworthy that the proposed modeling method is simple and practical. The modeling controlling parameters are reasonable and effective. It is also indicated that particle flow simulation of SRM with stochastic IRS rock blocks can reproduce the physical and mechanical properties of SRM well, including mesoscopic contacting characteristics of IRS particles, stress-strain relationship, negative dilatancy and positive dilatancy. The proposed method in this paper provides an effective way to further study the deformation and failure mechanism of SRM.
关键词
土石混合体 /
不规则颗粒 /
三维离散元 /
无底圆筒堆积试验 /
大三轴试验
Key words
soil-rock mixture (SRM) /
irregularly shaped (IRS) particles /
3D-DEM /
open bottom cylinder test /
large scale triaxial test
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