Abstract
In this study, a new Distinct Element Method (DEM) code had been developed, and a series of rock test simulations, such as uniaxial compression test, uniaxial tension test and Brazilian test are performed to investigate the effects of particle number and size distribution on macroscopic mechanical properties of rock models. Each simulation result was in good agreement with actual experimental results conducted by previous researchers, and the findings obtained from this study can be summarized as follows. The variation of calculated values of macroscopic mechanical properties decreases with increasing the number of particles. When the number of particles is 10000 or more, stable results are obtained as a rock test. Moreover, macroscopic mechanical properties of rock model, such as uniaxial compressive strength, Young's modulus and uniaxial tensile strength are significantly affected by porosity of the rock model. Since small particles fill the space among large particles, the porosity of the rock model decreases with increasing the maximum/minimum radius ratio of the particles, and particles are densely packed in the rock model. When the particle is closely arranged, the displacement of each particle is restrained with the adjacent particles even if the bond between particles breaks. As a result, the macroscopic mechanical properties of rock model increase greatly.
