Journal of the Korean Society of Mineral and Energy Resources Engineers ISSN:2288-0291(Print) 2288-2790(Online) 한국자원공학회지

Rock mass contains discontinuities and these discontinuities have a significant influence on the stability of an underground opening. To analyze the influence of the discontinuities, a discrete joint element analysis needs to be performed with consideration of realistic rock joint properties. In this study, a constitutive model for numerical modeling of the shear behavior of rough rock joints was presented and shear behavior of rock joint was simulated. Discrete finite joint element with zero thickness and six nodes is constructed. The fundamental assumptions were based on the classical elasto-plastic theory. The elastic behavior is represented by the shear and normal stiffnesses. To calculate the plastic displacements after yielding, the non-associated flow rule is adopted. Maksimovic\\\'s equation and empirical-joint strength formula proposed by Lee Sangdon & Lee Chung-In are used for yield and plastic potential functions. The changes of the joint roughness angle that occurred in pre- and post-peak shear strength curve were approximated by simple power expressions which are functions of accumulated tangential plastic work. Using discrete joint element, shear behavior of rock joint was simulated numerically. The results of the simulation showed that the proposed model could reproduce conspicuous phenomena commonly encountered in actual shear test of rock joints such as the hardening and softening phenomena and residual strength.