颗粒接触摩擦系数空间变异性对颗粒流双轴数值试验的影响

发布时间：2018-05-10 16:32

本文选题：双轴试验 + 离散元　；参考：《工程力学》2017年05期

【摘要】：提出了考虑颗粒摩擦系数空间变异性的砂土双轴剪切响应分析方法。采用随机场模型表征颗粒摩擦系数空间变异性,通过Karhunen-Loève展开方法离散接触摩擦系数随机场,编写了基于颗粒流程序PFC2D和MATLAB的随机模拟耦合分析程序。研究了摩擦系数空间变异性对密砂试样的双轴剪切响应影响规律。结果表明:1)提出方法可有效地考虑颗粒间接触摩擦系数变异性对土体材料双轴压缩宏观力学行为影响;2)密砂试样在剪切过程中的应力-应变关系曲线、体积-应变关系曲线的变化规律与颗粒间接触摩擦系数不确定性密切相关,在初始加载阶段随机模拟的偏应力曲线、体积应变曲线基本重合,继续加载后曲线开始发散;3)垂直相关距离对峰值偏应力均值与标准差影响明显大于水平相关距离。颗粒接触摩擦系数的均值对峰值偏应力的影响大于摩擦系数空间分布的影响。摩擦系数的空间分布会影响剪切带的形成位置。
[Abstract]:A biaxial shear response analysis method for sand considering spatial variability of grain friction coefficient is proposed. The random field model is used to characterize the spatial variability of particle friction coefficient. The random simulation and coupling analysis program based on particle flow program PFC2D and MATLAB is developed by using the Karhunen-Lo 猫 ve expansion method to discretize the contact friction coefficient random field. The influence of spatial variation of friction coefficient on the biaxial shear response of dense sand samples was studied. The results show that the proposed method can effectively consider the effect of the variation of contact friction coefficient between particles on the macro-mechanical behavior of soil material under biaxial compression. The variation of volume-strain relation curve is closely related to the uncertainty of contact friction coefficient between particles. In the initial loading stage, the deflection stress curve simulated at random basically coincides with the volume strain curve. The effect of vertical correlation distance on the mean value and standard deviation of peak deflection stress is obviously greater than that of horizontal correlation distance. The effect of the mean value of the particle contact friction coefficient on the peak deflection stress is greater than that on the spatial distribution of the friction coefficient. The spatial distribution of friction coefficient will affect the formation position of shear band.
【作者单位】：武汉大学水资源与水电工程科学国家重点实验室;武汉大学水工岩石力学教育部重点实验室;
【基金】：国家杰出青年科学基金项目(51225903) 国家自然科学基金项目(51329901,51679174) 湖北省自然科学基金创新群体项目(2014CFA001)
【分类号】：TU411

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