| 史旦达,杨晨捷,薛剑峰,王威.颗粒材料定向剪切特性的空心圆柱离散元模拟[J].水利学报,2018,49(8):917-925 |
| 颗粒材料定向剪切特性的空心圆柱离散元模拟 |
| Discrete element modeling of hollow cylinder shear behavior of granular material with fixed principal stress direction |
| 投稿时间：2018-03-20 |
| DOI：10.13243/j.cnki.slxb.20180233 |
| 中文关键词: 离散单元法 空心圆柱试样 主应力方向 剪切强度 各向异性 |
| 英文关键词: discrete element method hollow cylinder sample principal stress direction shear strength anisotropy |
| 基金项目:国家自然科学基金项目（41772273，51609315）；水力学与山区河流开发保护国家重点实验室开放基金项目（SKHL1704） |
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| 中文摘要: |
| 基于PFC3D离散元模拟平台构建空心圆柱型数值模型，研究了固定主应力方向条件下颗粒材料数值试样的定向剪切宏细观力学响应，重点分析了大主应力方向角对试样单调剪切特性的影响。数值建模中，采用“分离式簇墙”技术近似模拟室内试验橡皮膜的柔性边界效应，开发了顶部扭矩层颗粒旋转速度的“动态更新法”并较好地实现了剪应力的施加。结果表明，离散元数值模型能够较好地还原室内空心圆柱砂样定向剪切试验的应力路径和应力—应变响应；大主应力方向角α的变化显著影响数值试样的剪切强度，α=60°试样的峰值内摩擦角最低，且数值模拟得到的规律与已有的实际砂土室内试验规律相一致；数值试样剪切带的宏观演化在细观上可由试样内部局部孔隙比和配位数的变化规律来表征。 |
| 英文摘要: |
| This paper studies the macro and micro behavior of granular materials under torsional shear with fixed principal stress direction,using PFC3D discrete modeling on hollow cylinder tests,with emphasis on the effect of major principal stress angle on monotonic shear behavior. Stacked-wall boundaries are used to simulate the flexible membranes in hollow cylinder tests. An update controller method is developed to control the rotation velocity of particles at the top boundary,so that the shear force can be applied more effectively. The results from the simulation show that discrete element method can well simulate the stress path and stress-strain behavior of sand samples under torsional shear. The variation of the major principal stress angle α greatly affects the shear strength of the samples,and the pattern observed in the numerical modeling is similar to that in laboratory tests. The peak friction angle of the soil minimizes at the angle α=60°. The evolution of shear band is related to the variation of void ratio and coordination number in micro scale. |
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