High-density polyurethane rigid foam usability as liner support material in rock engineering

Abstract

To eliminate the problems like brittle material characteristics, low crack resistivity, low tensile strength values, late curing time and rebound problems of shotcrete liners, high density polyurethane rigid foams (PRF) were investigated as an alternative liner support material in this experimental and numerical study. Its rapid polymerization makes the PRF liners be able to supply support pressure in very early times in comparison with the shotcrete liners. Some fundamental tests were carried out to determine some support performance properties of a high-density PRF product with the foam density of 180 kg/m3. Additionally, a pilot PRF liner spraying application was practiced in an underground mine to investigate whether its application is advantageous in terms of eliminating the problems of shotcrete applications. In the field study, PRF liners were comparatively investigated with the shotcrete liner sprayed in the mine. Within the numerical part of this study, a series of finite element analyses were performed to investigate support performances of the PRF liners. According to the results of both experimental and numerical analyses, high density PRF liners were found to have proper load bearing capacities as a new liner support material, and the PRF liners were assessed to be a strong candidate to be popular in rock engineering. The findings from this study are promotive for new investigations to better understand support properties of the PRF liners for improving effectiveness of their systematic use.