采动岩体瓦斯渗流规律

Gas seepage in mined rock mass

为了实现瓦斯的高效抽放,解决煤与瓦斯的安全共采问题,基于煤岩介质力学性质及变形破裂过程的渗透特性,采用相似模拟试验和岩石破裂分析系统(RFPA2D)数值计算方法,模拟研究受采动影响的上覆岩层裂隙发育规律和瓦斯渗流规律。研究结果表明,随着开采工作面推进,顶板出现周期性垮落,老顶垮落步距约为12 m,其顶板破断角度约为50°,工作面和切眼上方裂隙发育基本对称,覆岩下沉曲线整体呈左右对称碗状;在卸压带内,煤体膨胀变形生成的大量次生裂隙,增加了煤体的渗透性,覆岩横向离层裂隙和竖向破断裂隙的动态发育变化,为实现煤与瓦斯的共采创造条件。工业性试验验证了受采动影响下推进距离和工作面瓦斯抽放量间呈非线性关系,为进一步理解采动影响下煤与瓦斯共采提供了理论基础和科学依据。

In order to achieve the efficient gas drainage and solve the safety problems associated with coal and gas co-mining,this study models the fracture development and gas seepage properties in overlying strata after mining using analogous simulation and rock fracture analysis system（RFPA） based on the mechanical properties of rock medium and seepage properties in phase rupture process.The study results demonstrate that with the advance of mining face,the coal seam roof collapses periodically with a main roof collapse distance of approximately 12m,and the roof breakage angle of about 50 degree.The fractures over the coal face and initial cut develop symmetrically.The sinking curve of overburden rock presents a symmetrical bowl shape.In the de-stressed zone,a large amount of secondary fractures are formed due to the large swell of coal body,which increases the coal fracture permeability and develops the dynamic alteration of transverse abscission fracture and vertical rupture fracture.This creates a favorable condition for coal and gas co-mining.Also,the industrial trial demonstrates that the advance distance of coal face and the amount of gas drained present a nonlinear relationship under the influence of mining,which provides a theoretical and scientific basis for further understanding coal and gas co-mining under mining influence.