100 / 2021-11-30 21:40:45

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

（6）职业安全与健康 > 4. 矿山动力灾害防控

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.