Influence of the Micro-deformation Characteristics of Binary Media on the Shear Behavior of Structural Plane

Binary media structural planes exist widely in natural rock mass and rock mass engineering, which are weak points of engineering and important factors that affect engineering stability. Thus, the mechanical behavior analysis of binary media has important engineering significance. The influence of the parallel bonding modulus ratio of binary media on the shear mechanical behavior of structural planes was investigated from the perspective of microscopic parameters on the basis of the numerical calculation method of discrete elements. A binary media model, including a flat structural plane, was established using the particle flow code. By changing the microscopic parameters, direct shear tests under different constant normal loads were conducted on the models with different parallel bond modulus ratios. The changes in shear stress, number of cracks, and normal displacement with shear displacement were recorded to investigate the influence of the parallel bond modulus ratio on the failure mode and failure development rule of the binary media. Two main results were obtained. First, the difference in modulus between two sides of the structural plane of the binary media greatly influences the peak strength, failure area, crack development, and location of the failure plane in the shear behavior of the binary media. Second, an increase in normal load will reduce the influence of the parallel bond modulus ratio on peak shear strength. Empirical formulas for strength parameters and modulus difference were proposed in this study on the basis of the simulation results. The shear strength calculation formula, including the microscopic parameters, was proposed and verified.