عنوان مقاله [English]
Many models have been proposed to predict the mechanical behavior of rock joints, but precise evaluation of effective roughness coefficient has been the most important limitation of these models. Geometry of asperities greatly influences the joint mechanical behavior, and these effects must be estimated by reliable and applicable methods. This paper deals with a method, which characterizes the rock joint surface in terms of roughness based on multi-scale decomposition using wavelet theory. Wavelet decomposition allows for distinguishing the small-scale and large-scale components of a wave. Here, joint geometryies is considered as a wave, and its roughness and undulation are regarded attributed to as the small-scale and large-scale components, respectively. Different scales of upper and lower joint surface roughness have been combined to produce the composite surface having asperities characteristics of both joint surface. Thus, the contribution of two surface components of the joint was considered separately in the shear strength criterion. It was found that peak shear strength is mainly influenced by both roughness and undulation, but the residual shear strength and dilation are mainly influenced by the undulation. The proposed shear model is capable ofhas capability to quantifying tative consideration of the roughness and undulation and helps to well understanding and modeling of the shear mechanism. The experimental test results verified the shear model predictions. results are well verified by comparison with experimental test results.