Abstract: Heterogeneous structural planes are extensively developed in nature, making it significant to study their shear characteristics, especially regarding anchored heterogeneous planes, for the stability analysis of engineering rock masses. The study selected sandstone and limestone heterogeneous structural planes with different wall rock strengths to conduct shear tests before and after anchoring, with their corresponding homogeneous structural planes serving as controls. Combining acoustic emission parameters and waveform frequency spectrum characteristics, the study analyzed the shear stress-shear displacement relationship of anchored heterogeneous structural planes, the shear failure mechanisms of joint planes, and the deformation and failure characteristics of bolts. The results indicate that the shear strength of the heterogeneous structural plane lies between that of the corresponding homogeneous planes and is closer to the one with lower strength. The variation in joint wall rock strength results in distinct shear failure mechanisms in heterogeneous and homogeneous structural planes: homogeneous sandstone planes demonstrate sliding type failure, primarily characterized by extensive friction and wear; homogeneous limestone planes exhibit shear failure dominated by the brittle fracture of asperities. While heterogeneous structural planes tend to exhibit a mixed failure mode characterized by the interaction between both types of failure. The deformation characteristics and failure modes of the bolts are influenced by the strength and roughness of the wall rock on both sides of the structural plane, with variations in wall rock strength resulting in asymmetric bending deformation of the bolts. There is a strong correlation between acoustic emission characteristic parameters and shear mechanical properties, with different ringing counts, energy peaks, and peak frequencies effectively reflecting various joint shear failure mechanisms.

Key words: rock mechanics, heterogeneous structural plane, bolt anchoring, shear properties, acoustic emission