【摘要】 防控底板突水危害的重点在于研究完整底板由隔水层到导水通道的演化过程。根据采矿过程中底板岩体在压–拉–压荷载下弹性刚度变化特点,以弹性模量作为损伤变量,采用双标量型D-P弹塑性损伤本构模型,由成庄矿工程地质条件为背景建立有限元模型,分析工作面推进过程中底板导水通道演化规律。得到主要结论如下:(1)采动底板中同时存在压、拉损伤破裂带,压缩、拉伸损伤分别超前、滞后煤壁产生,二者相互连通,形成斜穿工作面煤壁平面的导水通道。(2)底板破坏深度随顶板悬露面积增大而增加,并导致上一计算步煤壁处底板破裂深度二次加深。工作面煤壁位置处底板压缩损伤深度的增长速率在充填体影响下迅速减小(顶板初次垮落),并最终达到稳定(顶板周期垮落)。(3)充填体的弹性模量过低会导致破坏深度持续快速增加。在充填体作用下,底板岩体中张拉裂隙闭合,弹性刚度有所恢复,同时岩体渗透性降低。由注水试验所得监测结果与数值模拟成果基本吻合。更多还原

【Abstract】 The focus of prevention and control of water inrush from floor is to study the evolution of the intact floor from aquifuge to water-conducting. According to the elastic stiffness variation characteristics of floor rock mass in mining process,which beard loading of compression-tension-compression,using double scalar D-P elastoplastic damage constitutive model,finite element model was built based on the engineering geological conditions of Chengzhuang mine,the evolution law of water-conducting was analyzed in working face advancing process. The main conclusions are as follows:(1) Compression and tensile damage zones exist in mining floor. Compressive and tensile damage zones lead and lag coal wall respectively,both of them are connected,forming a water-conducting,which is inclined to pass through the plane of the coal wall.(2) Floor damage depth increases with the increase of the roof hanging area,and leads to the fracture depth increases again in last calculation step. Under the influence of filling body,the growth rate of the floor compression damage depth at the position of the coal wall is rapidly decreasing(the first roof caving),and finally reaching stability(the periodic caving).(3) Floor failure depth will rapid increase if elastic modulus of filling body is too low. Under the action of the filling body,the tension crack closure and the elastic stiffness of floor rock mass are restored,permeability of rock mass is decreased at the same time. The monitoring results obtained from the water injection experiment are in agreement with the numerical simulation results.更多还原