Determination of the mechanical parameters of the microstructure of rockfill materials in triaxial compression DEM simulation

An approach is devised to determine the mechanical parameters of the microstructure of Dalian limestone rockfill material (DLRM) in triaxial compression DEM simulation. The parameters of the rockfill materials include the crushing strength parameters of the particles and the mechanical contact model parameters (mesoscopic parameters). The crushing strength parameters of the particles in the DEM simulation are determined by a series of laboratory single-particle crushing tests. Weibull statistics are applied to describe the tensile strengths of the DLRM particles, and the particle size has only a slight influence on the Weibull modulus m. The size effect of the characteristic strength of the DLRM particles can be effectively described by an exponential function. The mesoscopic parameters are ascertained by the orthogonal test design and contour method. The orthogonal test design can reduce the ranges of values of the mesoscopic parameters and analyze the sensitivity of the mesoscopic parameters. The main mesoscopic parameters that affect each macroscopic response are captured by sensitivity analysis, and the mesoscopic parameters are quickly calibrated by taking advantage of the contours. The numerical simulation results obtained using the determined parameters agree with the results of the laboratory triaxial compression tests.