Numerical and experimental study on P-wave propagation across a rock joint with different orientations

Abstract

Determination of the required parameters in different science contexts using the ultrasonic wave velocity (UWV) has been one of the favorite topics of researchers in recent years. This paper presents numerical and experimental studies to investigate the effect of joint orientation on longitudinal wave (P-wave) velocity. The study started with a numerical simulation, in which a cylindrical sample containing joints with different orientations (0°, 15°, 30°, 45°, 60°, 75°, and 90°) to the wave propagation is modeled using the discrete element method. The results show that the P-wave velocity is dependent on joint orientation due to factors such as wave refraction and reflection, interference in the transmitted wave, and normal and shear stresses derived from the axial load. More precisely, the maximum velocity was recorded at zero-degree angles of joint and then reduced to 30°. The P-wave velocity increases slightly in the range of 30° to 45° and decreases sharply from 45° to 90° angles again. Finally, the numerical study is validated by laboratory tests, which show a close correlation.