含瓦斯煤体渗吸水变形特征实验研究

Experimental study on deformation characteristics of water imbibition of coal body containing gas

为了研究含瓦斯煤体渗吸水变形特征,利用自主设计搭建的承压瓦斯自然吸水实验系统,开展煤体在0.5、1.0、1.5、2.0 MPa瓦斯吸附平衡压力下的自然渗吸水实验。实验结果表明:气体吸附阶段,瓦斯压力越大,煤体横、纵变形量越大,纵向变形量约为横向变形量的2倍;自然渗吸阶段,煤体横、纵变形量均大于同一瓦斯压力下单纯气体吸附过程,实验系统环境压力值小幅升高,压力上升最大值为0.013 MPa,表明水渗吸同时存在瓦斯解吸过程;卸压泄水阶段,不同瓦斯压力下煤体的含水率分别为0.98%、1.05%、1.51%、2.24%,体应变和初始瓦斯压力二次相关,煤体体应变残余变形值较大,表明水渗吸作用后含瓦斯煤体变形的不可逆性和破坏性。

In order to study the deformation characteristics of water imbibition of coal body containing gas, a self-designed pressure-bearing gas natural water absorption test platform was used to carry out isobaric natural water absorption experiments in coal gas adsorption equilibrium pressures at 0.5, 1.0, 1.5, 2.0 MPa. The test results showed that: in the gas adsorption stage, with the increase of pressure, the horizontal and vertical deformation of the coal body showed a trend of increase, the vertical strain was about twice as the horizontal strain. In the natural water absorption stage, the transverse and longitudinal deformation of coal body is greater than that of pure gas adsorption under the same gas pressure. The ambient pressure of the experimental system increased slightly, and the maximum value of pressure increase was 0.013 MPa, indicating that the water imbibition was accompanied by gas desorption process. At the stage of gas desorption and water drainage, under different gas pressures, the water content of coal were 0.98%, 1.05%, 1.51%, 2.24%. The volume strain was secondarily related to the initial gas pressure, the residual deformation value of coal body strain was large, and it showed the irreversibility and destructiveness of gas-containing coal deformation after water imbibition.