Failure evolution and strength modeling of H-jointed layered sandstone under compression
Abstract
H-shaped joints, which consist of tensile and shear parts, are common in layered rocks and substantially affect rock failure and instability. To explore the mechanical performances of the H-jointed sandstone under different loading conditions. Uniaxial and confined compressive tests were carried out on H-jointed sandstone samples. The samples’ stress-strain responses, failure modes, AE activities, and strength were analyzed. The results show that the stress-strain curve has four phases: crack closing, elastic phase, elastic-plastic phase, and residual stages. The failure patterns of the H-jointed samples change from tension to shear as the joint dip angle increases. Tensile failure is dominant at lower inclination angles, whereas shear slip failure occurs along the joint surfaces at higher angles. Sliding along the joint surfaces with tensile cracking is observed at moderate angles. The joint roughness coefficient (JRC) significantly influences the samples’ mechanical behavior. A modified Hoek-Brown criterion that considers the joint dip angle and JRC is suggested for evaluating the strength of H-jointed rock samples under compression. This study provides a better understanding of the mechanical performance of H-jointed sandstone and a method to evaluate the strength.