Research on compression failure criteria and characteristics of rock-concrete assemblies with rough interfaces

The combination of rock and concrete lining structures is a typical composite structure in the field of engineering. This study is based on the concept of equivalent strain energy and establishes a mechanical equivalent model for rock-concrete assemblies (RCA). Assuming that both rock and concrete satisfy the Mohr-Coulomb criterion, we derive the shear failure criterion of the equivalent model considering the roughness of the rock-concrete interface. The applicability of the model was verified through uniaxial and triaxial tests on eight different types of RCA structures. The research results indicate that an increase in confining pressure enhances the strength of the RCA. When the confining pressure reaches a certain value, concrete only experiences shear failure, and no macroscopic cracks appear in the rock. The structure of the RCA tends towards isotropy. As the height ratio of the RCA increases, its strength decreases. At minimal concrete height ratios, the strength of the RCA gradually approaches that of concrete. This study can provide valuable insights for designing and evaluating stability in engineering rock bodies within diverse geological environments.