Types And Prevention Of Cretaceous Bed Separation Water Hazard In Shilawusu Mine

In Shilawusu coal mine in Ordos Basin,the coal seam thickness is large,the mining depth is large,the structure is simple,the roof overburden generally exists the thick integral structure Cretaceous medium-coarse sandstone,the Cretaceous lower Jurassic layered structure Anding formation mudstone-sandy mudstone,this kind of rock formation is easy to form the separated cavity during the mining process,receives the Cretaceous sandstone aquifer recharge,forms the Cretaceous high roof separation water hazard hidden danger.Taking the upper 08 working face of 221 Sheilausu Coal Mine as an example,using the means of field survey,theoretical analysis and numerical simulation,this paper focuses on the main line of "judging the location of water accumulation → the type of water inrush → the risk assessment of water inrush → the prevention and control of water damage in the separated layer".The results are as follows:(1)By means of theoretical analysis,analytical calculation and numerical simulation,the position of off-layer development in 221 upper 08 working face is identified.The results show that the off-layer of water in the vicinity of 08 working face is mainly concentrated in three layers: the inner of Anding group,the interface between Zhidan group and Anding group,and the inner of Zhidan group.At the interface between Zhidan Group and Anding Group,the scale of separation layer is the largest and the duration is the longest.(2)The fracture-production ratio of 221 upper 08 working face is 24.56,the leading height enters the Anding group but has not spread to the Cretaceous system,and the main hidden danger of water damage is concentrated at the interface between Zhidan Group and Anding Group.(3)The study found that the Cretaceous sandstone of Shilausu Mine has the characteristics of huge thickness,integral structure and low strength.The analysis shows that there are conditions of hydrostatic pressure surge inrush and dynamic water inrush in 221 Shang08 face.The risk assessment results are as follows :0～300m is dangerous area,300～2200 m is transition area,2200～2700 is dangerous area,The 2700～3200 m are serious danger areas.This paper puts forward the technical system of water hazard prevention and control of mining Cretaceous water monitoring holes in the adjacent working face of ground through diversion hole and underground horizontal grouting hole.The key technical requirements of design,construction and monitoring of each hole are given.The thesis has 63 figures,29 tables and 94 references.