A study to correlate LCPC rock abrasivity test results with petrographic and geomechanical rock properties

Abstract

Rock abrasivity is very much influenced by the petrographic and physico-mechanical properties of rock and hence its assessment from common geomechanical rock properties is helpful for rock engineers in estimating excavation costs. In this paper LCPC and CERCHAR abrasivity tests, as well as a complete suite of mechanical and physical rock properties tests, were conducted on 51 rock samples collected from different locations in Pakistan. Moreover, petrographical studies of 48 rock specimens were performed along with the computation of Schimazek9s F-value (F-value) and Rock Abrasivity Index (RAI). For the analysis of test results least square regression was employed. Initially the LCPC abrasivity coefficient (ABR) values were correlated with CERCHAR abrasivity index tests and reasonable relationships were observed. Statistically meaningful relationships were found between ABR and geotechnical wear indices (F-value and RAI). Possible correlations of LCPC test results with rock properties are also discussed. Finally multiple regression analysis was applied to find statistically significant correlation of ABR with petrographical and physico-mechanical rock properties. Test results show that RAI, Brazilian tensile strength and mean quartz grain size (O-qtz) prove to be the statistically best predictors of ABR from the rock properties determined. The developed correlations are specifically intended for rock engineers involved in designing excavation projects.