Shear strength model of joints based on Gaussian smoothing method and macro-micro roughness

The accurate evaluation on the shear strength of rough rock joints has always been the pursuit of rock mechanics workers. In this paper, based on the MATLAB image processing technology, the joint surface contour was firstly numerically reconstructed. Then, the Gaussian smoothing method was used to separate the macroscopic undulation characteristics from the microscopic roughness characteristics in the contour shape, and the morphological characteristic parameters were calculated respectively. Subsequently, a new shear strength model of rock joints containing both macroscopic and microscopic characteristic parameters was established by introducing the average undulation angle of topography parameters and the tangent angle corresponding to the root mean square of slope. Meanwhile, the numerical shear tests were designed and implemented in particle flow software PFC, and the numerical shear strength was employed to verify the rationality of the established model by comparing it with the predicted shear strength. The comparative results indicate that the proposed characterization method of joint roughness is capable of well considering the influences of macroscopic and microscopic characteristics of joints, and the predicted shear strength shows a great agreement with the numerical shear strength. The research can provide a good reference for the quantitative analysis of joint roughness and the estimation of joint shear strength.

Automated summary

This study utilizes MATLAB image processing technology to reconstruct the joint surface contour and establish a shear strength model of rock joints considering both macroscopic and microscopic characteristic parameters. Through numerical shear tests and comparative analysis, the model's rationality and accuracy in assessing joint roughness have been demonstrated.