150 / 2023-07-01 14:08:19

Experimental study on permeability characteristics of gas-bearing coal under dynamic loading

mine earthquake,gas-bearing coal,dynamic loading,mechanical characteristics,seepage characteristics

In recent years, mine earthquakes have occurred frequently and showed the possibility of inducing gas disasters, which has the characteristics of 'earthquake first and disaster later'. As a special dynamic load, the mechanical characteristics and gas seepage law of gas-bearing coal under the action of mine earthquakes are still unclear. In this paper, based on the improved dynamic triaxial test system, we propose an indoor test simulation method for gas seepage in coal rock under the action of mine earthquake, which can simulate the desorption and permeation test method of coal rock layer under the action of mine earthquake. Considering the adsorption process, the cyclic dynamic stress ratio(CSR) is introduced to discuss the dynamic properties and seepage law of gas-bearing coal under dynamic loading. The results show that the peak strain of the coal sample is negatively correlated with confining pressure and dynamic load frequency, while positively correlated with CSR. The seepage volume of coal body decreases with the increase of confining pressure and frequency, and the seepage volume shows an increasing trend with the increase of CSR. The variation law of permeability is consistent with that of seepage volume, and CSR has the greatest influence on coal permeability while frequency has the least influence on it. The research results are of great significance to reveal the law of coal deformation and gas seepage under the special dynamic load of mine earthquake.