Natural rocks show highly heterogeneous character on the micro- and meso-scales due to the randomly distributed defects. Based on the continuum mechanics framework

a scalar damage model is presented for simulating the deformation and failure process of rock material on the meso-scale. A spatial correlation scale factor is developed into the conventional Weibull random distribution model such that the spatial correlation characters of the physico-mechanical indices of rock material can be considered in numerical model. A series of uniaxial tensile tests on sandstone are chosen for parametric analyses aiming for investigation into the influence of spatial correlation scale factor in the random field on the load-cut opening degree curves and failure behavior. The modeling results demonstrate that the value of the spatial correlation scale factor for physico-mechanical indices of rock material can significantly influence the evaluation of mechanical parameters as well as the damage and failure pattern.