Research on the relationship between energy dissipation and stress drop in uniaxial compression failure of coal samples

Abstract

Compared with the energy dissipation of coal and rock failure, the more intuitive stress drop has certain practical significance for assisting the study of coal and rock failure characteristics and variation law of geophysical signals. And the stress drop is the macroscopic manifestation of energy dissipation. Most of the current research on energy dissipation and stress drop is only for one-sided research, without a comprehensive study on the relationship between the two. The relationship between the two is not clear, which restricts the application of the stress drop index. In order to solve the above problems, YAW−600 microcomputer controlled electro-hydraulic servo pressure testing machine is used to carry out uniaxial compression experiments on coal samples. The evolution characteristics of energy dissipation index and stress drop index in the whole process of coal sample failure under load and the relationship between them are studied and analyzed. Based on theoretical analysis, the relationship between energy dissipation index and the product of stress level and stress drop index is further studied. The results show that the energy dissipation index and stress drop index in the uniaxial compression failure process of coal sample have good response to the significant fracture of coal sample. And the indexes are in the same order of magnitude in numerical value, but they are not completely proportional. The energy dissipation rate is linearly related to the product of stress level and stress drop rate. And the energy dissipation is linearly related to the product of stress level and stress drop. The goodness of fit is 1 and 0.997 5 respectively. Compared with the energy dissipation index, the more intuitive product of stress level and stress drop index is more sensitive to the significant damage of coal samples, and has a burst characteristic. The research results clarify the relationship between energy dissipation and stress drop, and provide a certain theoretical support for the application of stress drop index. The relationship can be used for in-depth research on the coal rock failure characteristics and the variation law of geophysical signals such as acoustic emission, electromagnetic radiation and infrared radiation