Thin Rock Support Liners Modeled with Particle Flow Code

Abstract

Rapid setting, thin, spray-on polymeric liner materials are being developed for underground rock support in Canadian mines (Tannant, 2001). These materials have performance characteristics that lie between those of shotcrete and mesh. Twodimensional numerical models using Particle Flow Code (PFC) (Itasca, 1999) are used to model thin spray-on liners in simulated laboratory tests. The objectives were to determine how to model liners with PFC and based on these results to gain some insight about the support mechanisms provided by a liner. Direct tension tests and block punching tests were numerically simulated and used to calibrate the PFC micro-mechanical input parameters. Based on previous laboratory testing, the representative properties for a generic liner material are a tensile strength of 2MPa achieved at 50% elongation (Tannant, 2001). The tensile strength is equivalent to a rupture load of 2kN per millimeter of liner per linear meter. A typical thin spray-on liner thickness used to support rock around an excavation is about 4ram. Therefore, the PFC liner models were calibrated to break at around 8kN per linear meter of liner material.