DEM modeling direct shearing behavior of sand considering anti-rotation of particle

Considering anti-rotation of sand particles, two-dimensional Discrete Element Method (DEM) has been employed to reproduce direct shear behaviors of sand with different particle distribution sizes, so as to explore effects of anti-rotation of particle on responses of stress-displacement and dilatancy, the evolution law of shear stress, coordination number and vertical displacement of sand samples, and analyze the contact force chain, contact fabric and porosity of the samples after shearing.The results show that the anti-rotation ability of sand is enhanced, the torque of overcoming the relative rotation between particles is increased, and the peak shear stress, dilatancy and porosity in the middle of the sample are increased; with the increase of the anti-rotation coefficient, the coordination number decreases more obviously. The proportion of the contact number in the direction of 100 degrees-160 degrees to the total contact number decreases with the increase of the anti-rotation coefficient. The elliptical shape of the contact configuration becomes more flat, and the anisotropy of the contact force chain is more obvious; compared with fine sand, the coarse sand has greater shear capacity, more obvious dilatancy and larger porosity in the middle of the sample.The maximum minimum particle size ratio of the sample becomes larger, so that the shear strength of the sample is reduced, and the dilatancy is also weak.