(1. State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,Hubei 430071,China;2. University of Chinese Academy of Sciences,Beijing 100049,China)
Abstract:Based on the Brazilian splitting test,three-dimensional scanning and 3D printing technology,a surrounding rock-lining contact surface model is produced, and surrounding rock-lining contact samples were prepared using simulation materials. By shear test of the surrounding rock-lining contact samples,the shear properties and failure mechanisms of the surrounding rock-lining contact surface were studied,the main affecting factors were analyzed,and the formula of the shear strength of the surrounding rock-lining contact surface was explored. The results show that the shear curves of the surrounding rock-lining contact samples have two types of failure including ductility and brittleness. The normal stress,the roughness of the contact surface and the mechanical properties of the materials on both sides affect the shear deformation,shear strength and the failure mode of the surrounding rock-lining contact surface. By comparison,the material properties on both sides of the contact surface effect more than the roughness of the contact surface. The shear properties and failure modes of the contact surface depend not only on the magnitudes of the affecting parameters but on the combinations of the parameters. Introducing adhesion theory into Barton empirical formula according to the damage characteristics of the contact surface, a shear strength formula which is suitable for surrounding rock-lining contact samples was proposed, which embodies the unity of strength characteristics and influencing factors. The research results provide a test reference for the study of surrounding rock-lining interaction under earthquake action.