关键词: 波速, 脆性破坏, 微观机制, 临界信息, 应力比值

Abstract: This paper studies the relationship between wave velocity and rock brittle failure during the whole process of compression. The complete testing data for the stress-strain curve and the associated wave velocity-stress curve are obtained. The variation caused by internal cracking of the rock causes the corresponding variation of rock wave velocity, especially when the stress level reaches to 70%-80%. Based on the experimental results, it is shown that the stress at the critical point on the stress-strain curve is corresponded to that at the rapid deduced point on the wave velocity-stress curve, where the microcracks are rapidly growing. With the reducing of wave velocity, the travel times and discrete degree of S-wave and P-wave are sharply increasing. The amplitudes of S-wave and P-wave are reducing. However, the amplitude ratio between S-wave and P-wave is increasing. The Q values of S-wave and P-wave have a mutation phenomenon nearby the yield point of stress-strain curve. Considering the relation between wave velocity variation and stress-strain curve, this study shows that wave velocity and its characteristic parameters could be used as the sensitive parameter in the failure process. From this research, we can use the comprehensive information source to indentify the critical point of rock brittle fracture.

Key words: wave velocity, brittle failure, micromechanism, critical information, stress ratio