Abstract: Rock materials are featured with nonuniform material strength distribution and random material space fabric, both, in essence, belong to the heterogeneity of rock materials, having a profound impact on the mechanical properties of rock. In previous studies, the heterogeneity of rock material strength was usually simulated using finite element method and Weibull distribution function, and the relationship between heterogeneity and rock strength mechanical properties was obtained by defining the degree of heterogeneity with the coefficient of variation, which lacks consideration of the randomness of material fabric. In this research, a numerical model for the uniaxial compression test on heterogeneous brittle rock was established using the DDA (Discontinuous Deformation Analysis) method and the normal distribution function. The effects of heterogeneity and material fabric on rock strength were examined. Results demonstrated that with the growth of rock heterogeneity, the ultimate bearing capacity of rock attenuated. The greater the difference of elastic modulus between two contact elements in rock, the greater the strain difference, and the weaker the mechanical properties of the contact surface. In rock samples of the same degree of heterogeneity, the distribution of the weak points differs with fabrics, resulting in different rock fracture paths and mechanical properties.

Key words: rock mechanics, heterogeneity, material fabric, ultimate bearing capacity, coefficient of variation, normal distribution