Study on Damage Constitutional Relation and Attenuation Law of Elastic Wave in Fractured Rock Mass

Abstract

Abstract. Fissures in the high stress mass of deep buried had a great influence on mechanical properties and wave velocity of rock mass. Based on similarity theory, Rock like materials simulated deep buried marble of Jinping-II Hydropower Station. Under different fracture and different confining pressure, the triaxial compression test could be used in the model of the specimen. Collected the data timely and plotted the stress-strain curve and the stress-acoustic curve in the process of tests, then the model test-piece was equivalent to transversely isotropic material with multi group uniform distribution crack, established the damage constitutive relation which contains the acoustic wave velocity variable. The research achievement shows: In the triaxial compression test, the wave velocity increases with the axial compression when confining pressure is constant, the text advanced the speed by the first fast then slow way, the wave velocity increases with the axial compression is constant; the angle of fracture has a significant influence on acoustic wave velocity and attenuation of the energy of acoustic wave, under the same stress state, the larger the angle between the propagate direction of velocity and the fracture, the attenuation of sonic energy is more obvious, and the smaller the acoustic velocity. IntroductionThe existence of joints has great influence on the physical and mechanical properties of rock mass, the energy attenuation characteristics and wave velocity of elastic wave are changed. So the study of propagation and attenuation law of elastic wave in deep rock mass with joints is full of meaning.Many scholars and experts have studied the propagation and attenuation of elastic waves in fractured rock mass. In 1973,R.E.Thill[1] studied the relationship between the change of elastic wave velocity and the joints in rock. In 1997,R. Holt [2] got the wave velocity of elastic wave in the rock mass with different crack distribution through laboratory tests. In china, the research on the laws of the elastic wave propagation in rock date back from 1970.Gao longsheng and Ge huancheng[3] test the elastic wave velocity at different confining pressure which include ten rock samples. Huang chengxian and Song dawei[4] test the changing rule of the elastic wave velocity of rock in different confining pressure; Wang hongtu [5] etc. studied the dynamic elastic parameters of the fractured rock mass, the relationship between the elastic wave velocity and fracture. Zhao mingjie[6]studied the relationship among the elastic wave velocity, attenuation and stress based on the bearing and deforming of joint.Liu yonggui [7]etc. studied the reflective relationship when elastic wave go through the joint surface of basalt.In conclusion, scholars at home or abroad put lots of effort into the correlation between stress effect, crack distribution and wave velocity and the propagation attenuation of sonic waves in fractured rock mass, and lots of achievements have been obtained as well. However, there are less reports on the study ...