Upgraded ISRM Suggested Method for Determining Sound Velocity by Ultrasonic Pulse Transmission Technique

摘要

Ultrasonic testing is one of the most widely used nondestructive testing methods for rock material characterization (Lama and Vutukuri 1978). The method is based on the generation, transmission and reception of small-amplitude wave trains of adjustable pulse length and ultrasonic pulse frequencies. Wave propagation can be considered as transfer or passage of strain energy through a medium (e.g., Eringen 1980; Jaeger et al. 2007). In routine material testing, microstructural characteristics (encompassing mineralogy, size and shape distribution of voids and grains and their relative arrangements) of the medium determine the rate of energy dissipation, uniquely modify the frequency spectrum and define the velocities of different propagation modes, e.g., compressional and shear. Therefore, the wave velocities and their amplitude-frequency spectra are related to the material's physical and mechanical properties that are also strongly related to the microstructural characteristics. This relationship constitutes the basis of ultrasonic tests, but also poses great challenges for improvement of its precision and offers opportunities for a wider range of applications.