Abstract: Roughness is one of the important factors that affect the strength and deformation characteristics of jointed rock mass. In this paper, 3D printer has been employed to making molds firstly, and casting the different roughness joint rock specimens(joint roughness coefficient JRC = 2, 7, 12, 17 and 22). Triaxial compression tests are carried out on rock specimens with different roughness joints by using GCTS triaxial rock testing system of high temperature, high pressure and dynamic-static coupling loading to obtain the triaxial stress-strain curves. Then, based on the curves, we analyze the influence of JRC on the triaxial compressive strength and deformation characteristics of rock. At the same time, acoustic emission test system has been adopted to reveal the acoustic emission characteristic of the different roughness jointed rock specimens in the process of triaxial compression tests. Finally, the morphology of the joint surface is observed by digital three-dimensional video microscopy system, and the relationship between the peak strength of jointed rock specimens and JRC under different confining pressures has been discussed. The results show that the presence of joint results in a significant reduction in the strength of the joint rock specimen; JRC also has great influence on the morphology, quantity and spatial distribution characteristics of failure crack of rock. With the increase of the JRC value, the shear strength of rock joint increase, the triaxial compressive strength also increase, the rock specimen will changed from brittle failure to ductile failure.

Key words: joint roughness coefficient(JRC), strength characteristic, deformation characteristics, acoustic emission