To investigate the effect of loading rate on tensile strength of rock materials and morphologies of fracture joint surfaces

Brazilian disc tests were conducted on three rock samples (i.e.

granite

basalt and limestone) under different loading rates. The tensile strength was determined and the effect of loading rate on tensile strength was presented in detail. Three-dimensional (3D) scanning technique was employed to establish the digital terrain of fracture joint surface

and the effect of loading rate on fracture morphology of fracture surface was studied qualitatively. The relationships between surface roughness and loading rate and tensile strength were further analyzed by calculating the roughness index of fracture joint surface of three kinds of rock. The results show that tensile strength increases with the increase of loading rate

and under the double logarithmic coordinate system

it shows a good linear correlation between the parameters. According to the morphology of the fracture joint surface of rock materials

and from the perspective of the roughness of combination of qualitative and quantitative evaluation

it is found that the loading rate and tensile strength have a significant influence on the roughness of the fracture joint surface. The higher the loading rate is

the greater the tensile strength is

and the roughness of the fracture joint surface is. This study provides some reference for a better understanding of the relationship between the morphology index and mechanical parameters of the joint surface.