A correlation between ultrasonic pulse velocity and Schmidt hardness with engineering properties of rocks

As known, P–wave velocity and Schmidt hardness are non–destructive tests, which have been used for many years in geological, geotechnical and civil engineering as an index tests for a quick assessment of rocks engineering properties due to its rapidity and easiness, and non–destructiveness. The purpose of this study is to investigate the correlation between P–wave velocity and Schmidt hardness with some of engineering properties of carbonate rockbuilding stones by empirical equations. Moreover, we have compared the accuracy of P–wave velocity and Schmidt hardness to estimate the engineering properties of rocks. For this purpose, 15 types of carbonate rockhave been collected from various quarries of Iran and tested. The tests include the determination of P–wave velocity and Schmidt hardness, and engineering properties include the unconfined compressive strength, Brazilian tensile strength and point load strength. Using data analysis, empirical equations have been developed for estimating the engineering properties from P–wave velocity and Schmidt hardness. To check the validity of the empirical equations a t–test was performed, which confirmed the validity of the proposed empirical equations. Moreover, the results show that P–wave velocity appears to be more reliable than the Schmidt hardness for estimating the engineering properties. Consequently, we propose empirical equations avoiding from cumbersome and time consuming tests for determining the engineering properties of rocks.

Keywords:

P–wave velocity , Schmidt hardness , Engineering properties , Empirical equations