CORRELATIONS OF POINT LOAD INDEX AND PULSE VELOCITY WITH THE UNIAXIAL COMPRESSIVE STRENGTH FOR ROCKS

Abstract

Rock engineers widely use the uniaxial compressive strength (UCS) of rocks in designingsurface and underground structures. The procedure for measuring this rock strength has beenstandardized by both the International Society for Rock Mechanics (ISRM) and American Societyfor Testing and Materials (ASTM), Akram and Bakar(2007).In this paper, an experimental study was performed to correlate of Point Load Index ( Is(50))and Pulse Wave Velocity (Vp) to the Unconfined Compressive Strength (UCS) of Rocks. The effectof several parameters was studied. Point load test, Unconfined Compressive Strength (UCS) andPulse Wave Velocity (Vp) were used for testing several rock samples with different diameters.The predicted empirical correlations based on various test results indicate that the UCS could beobtained directly from measured (Vp), and then the Index Is(50) can be calculated by backsubstitution.