Numerical analysis of material modeling rock reinforcement in 2D FDEM and parameter study

Abstract This paper introduces a simplified smooth rock reinforcement modeling approach based on the 2D combined finite discrete element method (FDEM). The goal is to facilitate modeling the end grouting process and the full grouting process of rock bolts reinforcement, and to improve further understanding of the interaction between bolt, grouting, and host rock based on material mechanical behavior. The study analyzed the mechanical model and fracture mode extracted from experimental results using the rebar bolt specimen. This facilitated the study of the bond strength component of the rib. Then, the bond force-slip relationship was explored using physical modeling with different combinations of bolt and cover constraints, with different types of grouts and rocks. Corroboration of the laboratory axial pullout test was then conducted. A power law for the stress-displacement of the radial component of bond force was generated, to elaborate simplified modeling method and the data range of parameters in the diverse combination of constraining forces. Then, the action law was implemented into the material rock reinforcement model in FDEM. The verification process, done by comparing the bond force-slip curve with the physical modeling, shows the model can effectively reflect the action rule of rebar bolts. The model simplifies rebar bolt modeling and adds a new ability to model rock reinforcement features into FDEM, making the FDEM technology extend fundamentally.