Study on acoustic emission characteristics and permeability change law of coal samples under cyclic loading

This paper presents the results of an experimental study of acoustic emission characteristics and permeability of coal samples under cyclic loading. The tests were conducted using self-developed triaxial stress seepage experiment system by tested under different stresses levels. The test results showed that both the acoustic emission and coal permeability followed a pattern of reducing - stabilizing - increasing under cyclic loading. The curves representing the relationship between the acoustic emission and cyclic times and the permeability and cyclic time also had the same pattern. Their pattern showed a “U” shape at first, then developed to a “V” shape as the increase of stress. It is concluded that varieties for the acoustic emission characteristics and permeability of the coal samples are consistent, and associated with each other under cyclic loading.