Study on rock deformation and fracturing considering the spatially-correlated heterogeneity by discontinuous deformation analysis

To better capture the mesoscopic heterogeneity and its influence on the deformation and fracturing of rock, a Weibull spatially-correlated heterogeneity (WSCH) model is established based on the conventional Weibull random heterogeneity (WRH) model by incorporating a spatial correlation function within the discontinuous deformation analysis (DDA) framework, and Brazilian rock disc specimens are simulated as examples. It is indicated that the WSCH model brings continuous heterogeneous structures that better match the characteristics of real rock, and the continuity enhances with increasing spatial correlation radius r_a and spatial correlation impact factor Θ. The effects of r_a and Θ in the WSCH model are separately investigated via the simulations of designed specimens. Specimens with the WRH and WSCH models under the same heterogeneity index m are simulated and compared. Results indicate that, overall, the increase in m, r_a and Θ reduces dispersed microcracks, narrower the fracture zone, and bring remarkable influences on the equivalent stiffness and peak load of the disc. With the WSCH model, there are less dispersed microcracks, whereas the fracturing path is more prone to deviating, which align better with experimental results. The WSCH model also leads to obviously more pronounced discreteness in the equivalent stiffness of the disc.