Class Ratio Transform with an Application to Describing the Roughness Anisotropy of Natural Rock Joints

Rui Yong,Shigui Du,Lei Huang,Qinkuan Hou

doi:10.1155/2020/5069627

Abstract

In this study, we explore the potential of class ratio transform with an application to describing the roughness anisotropy of natural rock joints. Roughness smooth coefficient, used for suitably smoothing the roughness parameter values to realize an anisotropic model, is proposed to represent the apparent anisotropy of surface roughness. The geometric irregularities of roughness parameters in polar plots allow transforming to a regular roughness asperity pattern, which can be readily approximated by the ellipse function. The joint roughness coefficients in different orientations of natural rock joints were measured and revealed to be identical after applying the smoothing process using the class ratio transform method. The results show that the roughness smooth coefficient increases with sample size but decreases as azimuthal interval narrows. This method demonstrates the ability in describing the roughness anisotropy and inferring the roughness parameters Z2, Rp, and θmax∗/C+12 D.

Highlights

Rock joints have significant influences on the mechanical properties and deformation behavior of rock masses [1–6]
Mah et al [11] characterized the joint surface anisotropy based on the joint roughness coefficient values in different orientations. e results illustrated that the surface roughness of natural rock joints was anisotropic and the roughness varies in a random manner in polar plots
Several test samples were collected from the large exposed joint surfaces of the rock masses at Xiaolangdi Reservoir, Henan Province, China. e lithology of rock masses here is calcareous siltstone. e roughness samples were obtained from a persistent sub-vertical joint set of N70E, 83NW. e roughness surface contains several large exposures of natural, planar to undulating joint surfaces, and the roughness variations of the joint surface in different orientations are obviously susceptible to close observation and direct fragmentation touching

Summary

Introduction

Rock joints have significant influences on the mechanical properties and deformation behavior of rock masses [1–6]. Rock joints are formed through diverse, complex fracture mechanisms; this, coupled with the general complexities of rock masses, results in significant anisotropy of rock joint surfaces. E variation of the joint roughness in different directions has been recognized as an important source of anisotropic behaviors of rock joints. Bae et al [13] estimated the directional anisotropy of the joint roughness based on the half scan circle technique. Baker et al [16] developed an automatic technique to detect anisotropic features on rock faces by fractal analysis and plotting roughness along different orientations. Mah et al [11] characterized the joint surface anisotropy based on the joint roughness coefficient values in different orientations. E results illustrated that the surface roughness of natural rock joints was anisotropic and the roughness varies in a random manner in polar plots Mah et al [11] characterized the joint surface anisotropy based on the joint roughness coefficient values in different orientations. e results illustrated that the surface roughness of natural rock joints was anisotropic and the roughness varies in a random manner in polar plots

Results

Discussion

Conclusion