On the Causes of Water Inrush in Typical Karst Mining Area:Taking Longbao Coal Mine as an Example
In order to study the causes of water inrush from coal mining face in karst area,Longbao Coal Mine in northern Guizhou is taken as the test site.The controlled source audio-frequency magnetotelluric method is used to determine the water source and water channel,and the water inrush model is established with COMSOL to analyze the changes of fracture water pressure and water inrush during water inrush.The controlled source audio-frequency magnetotelluric method is used to prove that two water-conducting channels are formed in the T1y2 stratum near the water inrush point,five water-conducting channels are formed in the P3c stratum,and four water-conducting channels are formed in the P3l stratum.The mining of coal seam leads to the change of stress field and natural flow field of groundwater,and rock mass cracks are formed in the upper stratum and run through the T1y1 and T1y3 aquifuge.By simulating the water inrush after the conduction of different cracks and working faces,combined with the comprehensive analysis of the measured water inrush in the field,it can be seen that before the water inrush,the caving zone in the goaf has been connected to the No.I water channel,so that the water inflow has been maintained at about 20 m3/h.In the process of pushing mining,the roof is affected by mining,so that the mining face is connected with the No.Ⅱ water channel,resulting confined water in the aquifer T1y2 instantaneously pouring into the working face through the No.Ⅱ water channel,so that the water inflow suddenly increases to 100 m3/h.
万方数据
