Influence of Fracture Volumetric Intensity on Strength Anisotropy of Foliated Rock Masses: Insights From a Synthetic Rock Mass Modeling Approach

This paper presents a synthetic rock mass (SRM) methodology to investigate the influence of fracture volumetric intensity () on the strength anisotropy of foliated rock masses containing non‐persistent fracture sets. The approach integrates UAV‐based discontinuity mapping, discrete fracture network (DFN) modeling, and lattice‐spring discrete element modeling (LS‐DEM) to evaluate how fracture intensity progressively modifies rock mass strength and anisotropy. The methodology was applied to a foliated quartzite footwall from an open‐pit mining site. Discontinuity trace mapping and analysis were performed directly on point clouds, followed by DFN simulations constrained by field‐derived fracture intensity parameters. The results show that increasing SRM model size stabilizes the rock mass strength response, defining an anisotropic minimum stable volume, but does not ensure isotropic mechanical behavior. In contrast, increasing progressively reduces both the overall strength and the anisotropy index of the rock mass. The distribution obtained from the mapped slopes indicate that most field fracturing conditions correspond to highly anisotropic rock masses, with rock mass anisotropy index () predominantly ranging between 4 and 5. An empirical relationship between and was proposed based on the SRM results, allowing the generation of an anisotropy index distribution directly from a DFN‐derived fracture intensity distribution. This work provides a practical method for evaluating the applicability of homogenization approaches and isotropic strength criteria in fractured anisotropic rock masses, supporting failure criteria and stability analysis method selection for excavations in rock.