| At present,mining protective layer is the most simple and effective regional prevention and control measures for coal and gas outburst.Ⅲ11 rock working face in the Luling coal mine as a regional protective layer,it breaks through the traditional dangerous coal seam as a regional protective layer.The coal mine safety problem is worthy of further study.This paper takes the Ⅲ11 rock fully mechanized mining face in the Luling coal mine as the research object.First of all,on the basis of fully grasping the geological and hydrogeological data of the Luling coal mine,the water output of Ⅲ11 rock working face is predicted by "big well" method and hydrogeological comparison method.Secondly,four parameters porosity,compressive strength,consistent coefficient and deformation modulus,were selected as the indexes to evaluate the mechanical properties of rock.Through the fuzzy clustering analysis,the areas of the relatively strong disintegration of Ⅲ11 rock working face are divided.Then,the tendency model of Ⅲ11 rock working face is established,and the effect of overburden,overburden displacement,floor limestone water and the protective effect of the protective layer of Ⅲ11 rock working face are analyzed by UDEC numerical simulation software.Finally,the strike model of SF15 reverse fault is established,which has the greatest influence on Ⅲ11 rock working face,and the regularity of SF15 reverse fault activation and water inrush is studied by numerical simulation,and the areas are predicted that fault activation and water inrush may occur.The main research results are as follows:(1)The up-6# and down-6# drilling mudstone near the cut eyes of the Ⅲ11 rock working face are easily disintegrated,mining of the working face near the two drilling should strengthen preventive measures.(2)The UDEC numerical simulation of the tendency model shows: The influence area of Ⅱ mining area has not spread to the Ⅲ11 rock working face and the floor limestone water.After the mining of Ⅲ11 rock working face,the fractures of overlying strata are mainly developed of delamination fracture,vertical fracture development is minimal.Combined with the theory of "the fourth generation" and the development of a sandstone fissure in 9 coal floor,we can know that the roof of the Ⅲ11 rock face is seriously threatened by the stratifugic water.(3)Through the selected deformation expansion rate of more than 3‰ and the protective layer of vertical stress change greater than 51% as a critical standard for full pressure relief of the protected layer,the results show that the roof 8,9 coal and the bottom plate 10 coal seam pressure r elief effect is better,Ⅲ11 rock working face mining as a regional protective layer is more feasible.(4)Analysis of the strike model of SF15 reverse fault,Ⅲ11 rock working face through the fault after the lower plate promoting to 80 m,degree of activation of the roof fault is highest,and the thickness of the effective water barrier between the bottom fissure zone and the limestone water guide belt is 25 m,there is no threat of water bursting from fault activation.The research results provide guidance and reference for safety and prevention of water inrush in Ⅲ11 rock working face of Luling coal mine. |
