Discrete element method study of hysteretic behavior and deformation characteristics of rockfill material under cyclic loading

Granular geomaterials under different loading conditions manifest various behaviors, such as hysteresis. Understanding their hysteretic behavior and deformation characteristics is the basis for establishing a constitutive relation with excellent performance in deformation prediction. The deformation characteristics of crushable particle materials are analyzed through a series of cyclic loading tests conducted by numerical simulation. The hysteretic behavior is investigated from a particle scale. The increase in particles with contacts less than two may be responsible for the residual strain, and the particle breakage further promotes particle rearrangement and volume contraction. Both the accumulation of plastic strain and the resilient modulus are found to be related to confining pressures, stress levels, cyclic loading amplitudes, and the number of cycles. The plastic strain accumulation can be written as a function of the number of cycles and an evolution function of resilient modulus is proposed.