Assessing the empirical correlations between engineering properties and P wave velocity of some sedimentary rock samples from Damghan, northern Iran

Abstract

In the present research, engineering properties of some sedimentary rock samples were measured to assess the correlations between P wave velocity and physical, index, and mechanical properties. The physical properties include dry and saturated unit weights, porosity, and water absorption. The index properties contain Schmidt rebound hardness and slake-durability index. The mechanical properties include uniaxial compressive strength, point load index, Brazilian tensile strength, and block punch strength. For this purpose, a comprehensive laboratory testing program was conducted after collecting 15 various sedimentary rock samples of four rock types from northwestern parts of Damghan, northern Iran. In the following, empirical equations were developed by using regression analyses between P wave velocity and the measured properties. The obtained results showed that all of the properties have strongly correlated to P wave velocity. Hereof, the relationships between P wave velocity and porosity and water absorption were inverse linear. But, P wave velocity has direct linear correlations with the other properties. Prepared contour maps indicated that P wave velocity is more affected by porosity of the rocks. The curves with the 45° line (y = x) were extracted for evaluating the validity degree of concluded empirical equations which approved approximately close relationships between P wave velocity and the measured properties.