Research on Size Effect and Directionality of Roughness of Natural Rock Fracture Surface
To delve into the size-related effects and directional properties of the roughness on rock fracture surfaces,this paper focus on analyzing the roughness correction coefficient C within the refined formula of the cubic law,as it effectively characterizes the roughness of natural rock fractures.Since Louis first introduced the cubic law,numerous scholars have since proposed numerous modified formulas,including those by Zhang Youtian,Zimmerman,and Xiong et al.Through conversion,we acquire the calculation formula for the roughness correction coefficient and utilize collected natural fractures for related computations.High-precision 3D scanning technology was used to scan natural rock samples and acquire roughness data of fracture surfaces.By combining this data with publicly available high-precision CT scan data of rough rock fractures,we generate spatial coordinates.Both formulaic and numerical methods were used to calculate and analyze the roughness correction coefficient C.Using the formulaic approach,the roughness correction coefficient for sample sizes ranging from 10%to 100%of the fracture surface were calculated and varying results were obtained,which indicates that roughness exhibits a scale effect.According to the numerical method,a well-fitting ellipse was obtained,indicating that the roughness correction coefficient possesses directionality and can be expressed using tensor notation.This conclusion is further supported by calculating the JRC value of rough fractures and their surface and crack width fractal dimensions,revealing that the roughness of fracture surfaces exhibits scale effects and anisotropy.Upon further investigation,it is discovered that the roughness correction coefficient tensor or roughness tensor,when combined with average crack width,can be utilized to form a single crack permeability tensor that quantifies the rough surface in complex rough crack network models
NETL
NSTL
万方数据
维普
