Research on the anisotropy, size effect, and sampling interval effect of joint surface roughness

摘要

In order to explore the factors impacting on the roughness of natural rock joints, a new roughness parameter AHD (the average equivalent height difference) is proposed based on study of joint surface by using the 3D laser scanning technology. The new parameter AHD cannot only reflect the roughness anisotropy of joint surface, but the sampling interval effect and the size effect on roughness. To quantitatively characterize the roughness anisotropy of joint surface, a new anisotropy parameter A(AHD) is established based on the new roughness parameter AHD. The new parameter A(AHD) is more comprehensive and reasonable than the anisotropy parameter Ka obtained by Belem because of its consideration on surface morphology in all shear directions, while Ka only considers the largest and the smallest values of roughness parameter. Based on the new parameter A(AHD), the sampling interval effect and the size effect on the roughness anisotropy are further studied. The obtained results show that the roughness of joint surface is determined by shear directions, sampling intervals, and research sizes (which refers to window sampling size). It is found that the size effect on roughness depends on shear directions and stabilizes when research size increases to a certain value, while the roughness anisotropy is determined by sampling intervals and research size as well.