writer：Runsheng Lv; Bing Li; Zhimin Song, Gaofeng Liu and Jiangang Ren
keywords：Coal mass deformation; Mechanical model; Seepage; Effective stress; gas-bearing coal mass
source：期刊
Issue time：2016年
The absorption deformation characteristics and seepage rule of loaded gas-bearing coal masses are key basic problems in coal bed gas mining, gas prevention, and con-trol. This study considers the swelling deformation caused by the gas absorption of coal masses during coal bed gas mining, as well as the mechanical deformation and permeability change under the load. An isothermal adsorption instrument was used,as well as a heat-solid fluid coupling permeability test platform, in order to conduct isothermal adsorption testing and complete a stress-strain permeability test under different gas pressures. The test results showed the following: the absorption swelling deformation and absorption quantity of the coal under different gas pressures had a positive correlation and could not be ignored; and there was an inherent relationship among the internal absorption deformation, the external mechanical deformation,and the permeability rate of the coal mass. The effective stress of the coal mass was used as the link to build the mechanical model for the permeability rate and defor-mation coupling of the loaded gas-bearing coal mass, on the basis of consideration of the coal pore heterogeneity. The theoretical and practical verification showed that this model had a high accuracy, and was compliant with the actual circumstances. It was found through comprehensive research that in the built deformation and seepage mechanical model of the coal mass, the effective stress coefficient was the key pa-rameter linking the coal mass deformation and the permeability rate. Also, modifica-tions of the stress boundary conditions could be applied to the permeability calcula-tion under different conditions.