Research On The Mechanism And Application Of Roof Abscission Water Disaster In Longfeng Area Of Guizhou Provinc

The roof separation water disaster in Guizhou Province is frequent,and 22 attempted water inrush accidents have occurred in the mining of C9 coal seam in Longfeng area of Guizhou Province,which poses a great threat to the life safety of underground staff and the safety production of working face.Therefore,it is of great theoretical guidance and engineering significance to study the disaster mechanism of roof separation water disaster in Longfeng area of Guizhou Province.Based on the background of Longfeng area in Jinsha County,Guizhou Province,based on the theoretical of key strata to determined the composition and key position of C9 coal seam in Longfeng area.And the 5921 working face of Longfeng coal mine in Longfeng area is selected for geophysical prospecting and drilling verification.The mechanism of water inrush from separation layer in Longfeng area is obtained,and the corresponding prevention and control measures system of water inrush from separation layer of roof is proposed.Through this study,the main research results are as follows :(1)In this paper,the key strata of 39 layers in C9 coal seam in Longfeng area are identified.The results show that there are four key strata in C9 coal seam.The key layer 1 and the key layer 2 are broken successively.The key layer 3 is a sub-critical layer,and the key layer 4 is the main key layer.(2)By analyzing the mechanism of detachment development through the rock movement structure,it is concluded that the detachment space is formed below the key layer,and the formation of the detachment space is from small to large.When the key layer is broken,the detachment stops development,and gradually from large to small.(3)Combined with the theoretical analysis results of the key layer and the predicted height of the water flowing fractured zone,the development height of the water flowing fractured zone can reach the height of the limestone of the Changxing Group,which is the sub-critical layer.The separated water formed under the sub-critical layer can be connected with the working face through the water flowing channel formed by the water flowing fractured zone,resulting in the flow of the separated water to the working face.(4)Taking 5921 working face of Longfeng Coal Mine as an example,geophysical prospecting and drilling tests are carried out,and drilling verification is carried out with geophysical prospecting results as reference.Low resistance abnormal area by drilling verification in two sections a cycle of water gushing,non-abnormal area by drilling verification no water gushing.And according to the key layer theory combined with geophysical exploration and drilling test,the key position of 5921 working face is limestone of Changxing Group.(5)Combined with theoretical analysis and test research,the prevention and control system of separated water disasters is established,mainly including the advance drainage of roof water,the control of reasonable mining speed and the cracking of the instability of key strata.