On the accuracy of the in-situ Schmidt hammer test on carbonate rocks

The handy and practical Schmidt Hammer (SH) has been used for both in-situ and laboratory measurements of hardness and estimate of the Unconfined Compressive Strength (UCS) of rocks. Geological features such as structure, texture and mineralogy influence the mechanical properties of rock masses and these factors should be carefully evaluated for each testing location. In the work presented here, a case study was chosen to demonstrate and discuss the effectiveness of particular geological circumstances on in-situ SH test results concerning different carbonate rocks. Three different types of limestones, chalky, marly and dolomitic are available in the Tertiary carbonate sequences at the studied area which is Jabal Hafit, south of Al Ain city, United Arab Emirates (UAE). The results clearly show that rapid changes in carbonate rocks structure, texture and even mineralogy always create problems in generalizing the mechanical properties which are essential parameters in geological and engineering practices.