Numerical simulation of the reinforcement effect of rock bolts in granular mixtures

Abstract

The reinforcement effect of rock bolts in granular mixtures is studied by the mesoscopic numerical simulation method. The granular mixtures consist of 3D polyhedral granules. The particle size distribution (PSD) is based on stochastic simulation technology. Simulations of rock bolts and granular mixtures are conducted by ABAQUS/Explicit program. The bolted granular material is analysed in macroscopic and mesoscopic scales. Various factors on the mechanical properties of the granular mixture are studied, including spacing, PSD, the prestress, porosity of the granular material, the length of the bolts and the diameter of supporting plates at the bolt ends. The simulated results reflect the deformation and reinforcement effect of different bolted granular structures. The macroscopic results are closely related to the evolution of the mesoscopic fabric. Without considering the bolt length, if the bolt spacing is less than three times the average particle diameter, a stable structure can be formed using the rock bolts. Based on the samples in this paper, the list of ranking of importance of parameters on the degree of reinforcement is porosity > granule size > bolt spacing > supporting plate diameter > bolt prestress > bolt length.