Benmebarek Mohamed Amine, Movahedi Rad Majid
Department of Structural and Geotechnical Engineering, Faculty of Architecture, Civil Engineering and Transport Sciences, Széchenyi István University, Egyetem tér 1, 9026 Gyor, Hungary.
Materials (Basel). 2023 Mar 3;16(5):2077. doi: 10.3390/ma16052077.
This paper deals with the micro and macro behaviors of coarse sand inside a direct shear box during a geotechnical test. A 3D discrete element method (DEM) model of the direct shear of sand was performed using sphere particles to explore the ability of the rolling resistance linear contact model to reproduce this commonly used test considering real-size particles. The focus was on the effect of the interaction of the main contact model parameters and particle size on maximum shear stress, residual shear stress, and sand volume change. The performed model was calibrated and validated with experimental data and followed by sensitive analyses. It is shown that the stress path can be reproduced appropriately. For a high coefficient of friction, the peak shear stress and volume change during the shearing process were mainly affected by increasing the rolling resistance coefficient. However, for a low coefficient of friction, shear stress and volume change were marginally affected by the rolling resistance coefficient. As expected, varying the friction and rolling resistance coefficients was found to have less influence on the residual shear stress.
本文研究了土工试验中粗砂在直剪盒内的微观和宏观行为。使用球形颗粒建立了砂土直剪的三维离散元法（DEM）模型，以探讨滚动阻力线性接触模型在考虑实际尺寸颗粒的情况下再现这种常用试验的能力。重点是主要接触模型参数与颗粒尺寸的相互作用对最大剪应力、残余剪应力和砂体体积变化的影响。对所建立的模型进行了校准，并与实验数据进行了验证，随后进行了敏感性分析。结果表明，应力路径能够得到合理再现。对于高摩擦系数，剪切过程中的峰值剪应力和体积变化主要受滚动阻力系数增加的影响。然而，对于低摩擦系数，滚动阻力系数对剪应力和体积变化的影响较小。正如预期的那样，发现改变摩擦系数和滚动阻力系数对残余剪应力的影响较小。
