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双滑移自由转动模型、双剪模型和双滑移转动率(DSR2)模型这3种双剪类模型均是基于运动理论的塑性模型,其关键区别在于转动率参量的选取。采用改进后的NS2D离散元程序,对长短轴比例分别为1.4和1.7的椭圆颗粒试样进行不排水单剪试验以验证上述双剪类模型中转动率参量选取的合理性。数值试验结果表明:①双滑移自由转动模型中的限定条件因未考虑能量消散过程中颗粒转动的影响而过于严格;②双剪模型中转动率参量为主应力方向变化率的假定与数值试验结果差距显著;③DSR2模型中采用平均纯转动率(APR)可很好地预测转动率参量的变化,且该模型可用于砂土非共轴微观机制的研究;④参量APR能考虑剪切过程中颗粒转动对能量耗散的影响,可将离散介质力学和连续介质力学有机结合起来,是运动模型中合理且重要的参量。
Double-slip free-wheeling model, double-shear model and double-slip rate of rotation (DSR2) models are all plastic models based on motion theory. The key difference is the selection of the rotation rate parameters. The modified NS2D discrete element program was used to test the irrational single-shear tests on elliptical particles with major axis and minor axis respectively of 1.4 and 1.7 to verify the rationality of the parameters of the above two-shear model. The numerical results show that: (1) the constraint condition in the double-slip free-wheeling model is too strict due to the failure of particle rotation in the energy dissipation process. (2) The assumption and numerical test of the rate of change of the main stress in the double shear model (3) The average pure rotation rate (APR) in the DSR2 model can predict the change of the rotation rate parameter well, and this model can be used to study the non-coaxial microscopic mechanism of sand soil. (4) The parameter APR can consider the shear process The influence of particle rotation on energy dissipation can combine discrete medium mechanics with continuum mechanics and is a reasonable and important parameter in motion model.