Parametric study of smooth joint parameters on the behavior of inherently anisotropic rock under uniaxial compression condition

Abstract

Inherently anisotropic rocks are modeled with the use of two-dimensional Discrete Element Methods (DEM). In the simulated anisotropic rock sample, the rock matrix is modeled as an assembly of rigid particles and the existence of weak layers is directly represented by imposing individual smooth joint (SJ) contacts with same orientation into the rock matrix. The properties of a SJ contact include normal and shear stiffness, normal strength, cohesion, and friction angle. A systematic study is conducted to investigate the influence of these parameters on the macro behaviors of anisotropic rocks with different anisotropy angles under uniaxial compression condition. The Young’s modulus is found to increase significantly with the SJ normal stiffness when the anisotropy angle is low (0o-30o). The USC increases with the SJ normal strength at high anisotropy angle (β>60°) while cohesion raises the UCS at medium anisotropy angle (30o-60o). The influence of friction angle is not significant. Understanding the influence of each parameter is of great importance for the calibration of micro parameters to represent certain type of rock. A general process for the calibration of micro parameters to reproduce the strength and deformation behaviors of different types of anisotropic rocks is proposed.