Macro-Micro Failure Mechanisms and Damage Modeling of a Bolted Rock Joint

Abstract

The anchoring mechanism of a bolted joint subjected to a shear load was investigated using a bilinear constitutive model via the inner-embedded FISH language of particle flow code based on the discrete element method. The influences of the anchoring system on the macro-/micromechanical response were studied by varying the inclination angle of the bolt. The results indicate a clear relationship between the mechanical response of a bolted rock joint and the mechanical properties of the anchoring angle. By optimizing the anchorage angle, the peak strength can be increased by nearly 50% relative to that at an anchorage angle of 90 ∘ . The optimal anchorage angle ranges from 45 ∘ to 75 ∘ . The damage mechanism at the optimal anchorage angle joint is revealed from a macroscopic mechanical perspective. The concentration of the contact force between disks will appear in the joint and around the bolt, resulting in crack initiation. These cracks are mainly tensile cracks, which are consistent with the formation mechanism for compression-induced tensile cracks. Therefore, the macroscopic peak shear stress in the joint and the microscopic damage to the anchoring system should be considered when determining the optimal anchoring angle to reinforce a jointed rock mass.

Broad-spectrum fracture toughness of an anisotropic sandstone under mixed-mode loading

“…This phenomenon was similarly observed in other geo-materials such as bedded coal (Fig. 10j) [32] and a Chinese sandstone (Fig. 10m) [27].…”

DEM simulation of mortar-bolt interface behaviour subjected to shearing

“…The URBM can simulate the debonding process of the mortar-bolt and mortarrock interfaces at large displacement although the accuracy is meshdependent due to the DDA code. Wang et al [24] investigated the micromacro failure mechanisms of a bolted joint using the discrete element method (particle flow code 2D). The continuum-based numerical methods have the limitation of investigating micromechanical behaviour of a rock or a solid material, thus the micro-mechanisms underlying the failure process cannot be known [25].…”

Experimental Study on Influence of Joint Surface Morphology on Strength and Deformation of Nonthrough Jointed Rock Masses under Direct Shear

“…Fan et al [19] used the PFC program to establish numerical models containing one open flaw and two circular openings. e digital image correlation (DIC) techniques are employed to study the crack coalescence process of specimens with two dissimilar layers under uniaxial loading [20,21].…”