The influence of joint distribution characteristics on the mechanical properties, fracture mechanisms, and energy characteristics of rock masses under stress conditions

The mechanical properties, fracture mechanisms, and energy characteristics of jointed rock masses under stress conditions are crucial theoretical underpinnings for the monitoring and reinforcement of rock engineering. In this study, rock mass images with various joint distribution characteristics are constructed. By integrating mesoscopic damage mechanics, statistical strength theory, and continuum mechanics, and using digital image processing within the DIC-refined RFPA method, the jointed rock mass images owning different joint distribution characteristics are rendered into non-uniform numerical models. Their strength and deformation characteristics, fracture features, and energy evolution patterns under stress condition are investigated. Further, the impact of joint distribution characteristics on micro-crack quantity indexes (MCQIs) and micro-crack energy indexes (MCEIs) is examined, and then they are organized into rankings. The study reveals that, when subjected to both lateral pressure and vertical compression condition, the compressive strength (CS) and equivalent deformation modulus (EDM) are lower for columnar jointed rock masses (CJRMs) and rock masses with X-type cross cracks (RMXCCs), while they are larger for intermittent jointed rock masses (IJRMs) and rock masses with V-type cross cracks (RMVCCs). The MCQIs and MCEIs appear earlier on the strain axis for RMXCCs and rock masses with Ttype cross cracks (RMTCCs). The magnitudes of MCQIs and MCEIs for IJRMs and RMTCCs are lower, while they are higher for CJRMs and rock masses with trident-type cross cracks (RMTRCCs). Under the concurrent normal stress and shear condition, whether the magnitude of MCQIs in rock masses with en-echelon joints (RMEJs) is higher than that in CJRMs depends on the specific joint dip angles. These findings can serve as a foundational framework for monitoring, reinforcing, and operating maintenance of rock engineering.