Combination of the Physical and Ultrasonic Tests in Estimating the Uniaxial Compressive Strength and Young’s Modulus of Intact Limestone Rocks

Abstract

Geo-mechanical parameters of intact rocks like uniaxial compressive strength (UCS) and young’s modulus (E) have been essentially evaluated for many objects. These parameters are obtained by standard UCS tests that are destructive, expensive, and time-consuming task. By using nondestructive methods such as the ultrasonic or physical tests, the parameters can be indirectly predicted. Consequently, presentation of multiple linear regression equations between destructive and nondestructive parameters is proposed in this paper. In order to predict the UCS and E in terms of density (ρ), porosity (n), primary wave velocity (Vp) and shear wave velocity (Vs), 482 rock samples’ data of five sedimentary rock types (in range from limestone to marl) from five different dam sites (located in Asmari formation, southwest of Iran) were analyzed. After regression analysis of the test results, the best fit equations are selected–equations with four independent variables (ρ, n, Vp, Vs) and high coefficients of determination (R2) on levels of 0.91 for UCS and 0.88 for E. These equations are simple, practical, and accurate enough to apply. They also can be used in practice for prediction purposes with acceptable accuracy.