DEFORMATION CHARACTERISTICS AND WAVE VELOCITIES OF HARD ROCK BLOCK WITH CRACKS AT LOW STRAIN LEVELS

Abstract

Dynamic loading tests are carried out for test specimens of hard rock blocks with cracks. Stress-strain relations at low strain levels are observed and their deformation characteristics are studied. Wave velocities evaluated from dynamic loading tests are compared with those due to resonance method and ultrasonic method. There are some differences among these wave velocities and their relations varies according to the density of cracks in the specimens of hard rock blocks. Strain rate dependency of wave velocity and the effect of the distance between cracks and routes of wave propagation on wave velocity are investigated.