Characterization of Joint Set Effect on Rock Pillars Using Synthetic Rock Mass Numerical Method

Abstract

AbstractIn this paper, a synthetic rock mass (SRM) method is used to numerically characterize the effect of joint sets on rock pillars. The SRM model is constructed by explicitly inserting discrete fracture network into a particle assembly. Conceptual SRM models show that pillar-loading capacity is weakened by inserted joints. Pillar peak strength is lower when inserted joints favor shear sliding of rock blocks, and strength becomes higher when pillar failure is controlled by fragmentation of intact rocks. Meanwhile, loading capacity is weakened when longer joints are simulated. The effect of joint sets on pillar modulus is similar to the observed effect on peak strength. Pillar failure behaves as a continuous shear failure when the inserted joints are inclined and changes into intact rock splitting when the joints become vertical. The SRM method is then used to characterize the joint set effect on real pillars in the Doe Run mine. A pillar model with a width/height ratio of 0.8 is initially constructed o...