Correlation between Ultrasonic Pulse Velocities and Physical and Mechanical Properties of Rocks
The objective of this study is to correlate the static Young’s modulus with the dynamic Young’s modulus for eight different rock types. Intact rock core specimens and specimens with one, two and three induced fractures normal to the core axis have been used in the ultrasonic pulse velocity measurements and in the static loading test. The P and S-wave velocities are determined along with the fracture apertures and stiffness. The results indicate that both P and S-wave velocities decrease with increasing number of fractures in rocks. The static and dynamic Young’s moduli, exponentially decrease with increasing number of fractures. They can be correlated using exponential equations. The rate change of the Es-to-Ed ratios tend to be similar for all rocks tested here. For all rock types, Ed for intact rocks is about twice of the Es. The differences become smaller for rock specimens containing larger number of fractures.
Keywords - Dynamic Young’s modulus (Ed), Static Young’s modulus (Es), Ultrasonic pulse velocity (UVP), Tension-induced, Joint normal stiffness (Kn), Change of fracture aperture (△e).