Experimental study on evolution characteristics of coal seam parameters under true triaxial cyclic mining
cyclic loading and unloading,initial gas pressure,strain,change in gas pressure
Occupational Safety and Health > 4. Prevention and Control of Mine Dynamic Hazards
Draft Paper Accepted
Jiabo Geng / Jiangxi Province Key Laboratory of Mining Engineering
Jiangtong Liu / Jiangxi Province Key Laboratory of Mining Engineering
Gaoxiong Zeng / Jiangxi Province Key Laboratory of Mining Engineering
Dongming Zhang / Jiangxi Province Key Laboratory of Mining Engineering；tate Key Laboratory of Coal Mine Disaster Dynamics and Control
Jiang Xu / tate Key Laboratory of Coal Mine Disaster Dynamics and Control
In order to further explore the evolution characteristics of coal seam parameters in circular mining, physical simulation tests on the influence of cyclic stress on coal seam parameters under different initial gas pressures were carried out by using a large true triaxial physical simulation test rig, and the evolution characteristics of gas pressure and coal seam strain with the number of cycles and gas pressure were discussed. The test results showed that in the process of cyclic loading and unloading, the coal body is broken, new pores and fissures are generated, and more free gas is absorbed, which makes the pressure of the coal body decrease; Both the strain and gas pressure of coal seam change with the loading and unloading of cyclic load, and the changes of the two parameters reach the maximum value at the first loading; With the increase of the number of cycles, the increase and decrease of the gas pressure during loading and unloading show an increasing trend, and the closer the distance to the pressure device, the greater the change; With a lower initial gas pressure, the greater increase of pressure caused by the first loading.However, in the subsequent loading and unloading process, the greater initial gas pressure cause the greater gas pressure change.