采场顶板O-X型垮落空气冲击灾害预测

Forecasting of air impact disaster induced by O-X roof caving type in mining face

神东矿区煤层地质赋存特点是浅埋深、薄基岩及厚煤层,工作面长度大和推进距离远。开采实践中,均发生过采场顶板大面积垮落的空气冲击灾害。依据采场顶板初次来压的O-X型垮落模式,采用顶板关键块体的回转下沉理论,建立了采场顶板O-X型垮落的空气冲击灾害的耦合模型,用数值差分解法研究了顶板O-X型垮落过程中巷道空气冲击灾害的变化规律。结果表明:1)与顶板自由落体模型和整体切落耦合模型相比,空气冲击灾害时间延长。2)巷道口附近最大的空气冲击灾害发生在顶板垮落结束前,距顶板垮落结束尚有0.21 s的时差。3)距离出口越远,冲击风流速度越低,空气冲击灾害威胁愈小。4)在巷道的不同位置和不同时刻,冲击风速大小不同,在选定密闭墙位置的情形下,可按最大临界流速设计给定材料结构的抗冲击墙厚度参数。

In Shenfu-Dongsheng mining area,the coal bed geological occurrence is characterized by the shallow buried depth, thin bedrock and thick coal seam. The working face length is large and mining distance is long. In mining practices, the air impact disaster of roof caving in stope has occurred. Based on roof caving of type O-X in initial weighting in mining faces, the air impact coupling model caused by face＇s O-X type roof caving of is built with the key block＇s rotating and the subsidence theory. The air impact disaster＇s varying law in roadways induced with roof caving of O-X type is studied by using numerical solutions. The conclusions by practical example are as follows： 1） Compared with free-fall model and integral shearing-caving coupling model, air impact time lengthens. 2） The maximum value of air impact disaster near roadway exist occurs before roof caving finished, there is 0.21 s to the roof caving ending. 3） The outlet of the gate exist lowers the impact air-flow velocity and mitigates the air impact disaster＇s influence. 4） The impact air-flow velocity is different at various position of gates and time. The height of anti-impact wall under given material can be designed according to maximum critical velocity of air impact flow if the position of seal wall was selected.