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 designing surface and underground structures. The procedure for measuring this rock strength has been standardized by both the International Society for Rock Mechanics (ISRM) and American Society for 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 effect of several parameters was studied. Point load test, Unconfined Compressive Strength (UCS) and Pulse 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 be obtained directly from measured (Vp), and then the Index Is(50) can be calculated by back substitution.

Keywords

• Rocks, Uniaxial Compressive Strength (UCS), Modulus of Elasticity(Es), Point Load Index (Is(50)), Pulse Wave Velocity (Vp).