煤体吸附-解吸瓦斯变形特征实验研究

在煤层瓦斯抽放过程中，煤体瓦斯处于吸附-解吸状态，煤体发生膨胀和收缩。利用自主设计的煤体变形实验装置，分析了杜儿坪煤矿原煤在不同方式下吸附-解吸全过程中变形特征。实验结果表明：煤体变形量随着瓦斯压力的增加而增大，垂直层理方向变形量大于平行层理方向变形量；煤体在一次加压吸附实验中分为变形下降阶段、变形快速上升阶段和变形平稳上升至稳定阶段3个阶段；等梯度加压吸附-降压解吸过程中，0→0.5 MPa阶段变形量最大；等梯度加压吸附煤体变形量大于一次加到目标压力值的吸附煤体变形量，且等梯度解吸煤体残余变形量较大；煤体吸附-解吸变形可分为充气下降阶段、吸附快速上升阶段、吸附变形平稳上升至平稳阶段、解吸变形快速下降阶段和解吸平稳下降至稳定阶段。

Experimental study on the characteristic of coal deformation during gas adsorption and desorption process

In the process of gas drainage,along with the gas adsorption and desorption,the coal matrix can be swelled and shrunk induced by gas migration.The self-made experimental system was used to study the characteristic of coal deformation during gas adsorption and desorption process under different modes using Duerping coal samples.The results show that the deformation of coal increases with the gas pressure increases,and the deformation along the direction of vertical bedding is bigger than that along the parallel bedding.The deformation process of coal at increased pressure at one time can be divided into deformation declining stage,deformation rapid growth stage and deformation slow growth and steady stage.In the process of pressurized adsorption and depressurized desorption at same gradient,the coal deformation from 0 to 0.5 MPa is biggest,and the coal deformation of increased pressure at the same gradient is bigger than the adsorption mode of increased pressure at one time.The residual deformation of increased pressure at the same gradient is bigger.The deformation process of coal adsorption/desorption is divided into decline stage,rapid growth stage,slow growth and steady stage,rapid decline stage,and desorption slow decline and steady stage.