Research And Engineering Application Of Key Technology Of Grouting Seepage Control In Matoumen Strong Water-rich Coal Body Of Balasu Coal Mine

The north area of Yuheng mining area is the main area of coal production that will be constructed and developed in the future.It is located in the middle of the Jurassic coalfield in northern Shaanxi.The coal seam burial depth of the coal mine in the middle of the area is basically more than 450 m,and there are a large number of water rich coal seams.It is rare in the world that the water hazard of deep high pressure coal seam caused by this affects the mine infrastructure.The problems caused by the water rich coal seams,such as water seepage in the shaft and difficult to uncover coal in the rock roadway,seriously restrict the safe and efficient construction of the coal mines in the water rich coal seams in the mining area,and also seriously restrict the safe and efficient production of the coal mines in the later period.As the first large-scale intelligent mine to be built by Yanchang Mining Company,the No.2 coal seam mainly mined by Balasu Coal Mine is a strong water rich coal seam,and the No.1 return air shaft,No.2 return air shaft,auxiliary shaft and the pipe way of the shaft bottom yard are seriously disturbed during construction.The water inrush from the coal seam has seriously restricted the shaft construction and mine construction.During the investigation,it was also found that the coal wall area at the Matou Gate of No.2 Coal Seam had the phenomenon of wall heave to varying degrees.In view of the above problems,this research is based on the Matoumen project of the return air shaft in Balasu Coal Mine.By means of theoretical analysis,numerical simulation,laboratory test and field test,the research contents are as follows: the design and construction parameters of grouting reinforcement for strong water-rich coal,the key factors affecting the deformation and failure of strong water-rich coal,and the research and development of new quick-setting grouting materials:1.Based on theoretical analysis,construction investigation and other research methods,it is determined that the coal seam water of Coal Seam 2 # is the key water filling source for the Matou Gate of the return air shaft,and the water filling channel is the coal seam fissure.The roof and floor structure of the coal seam presents a complex stratum structure of "upper containing lower resistance",which is difficult to penetrate water.2.With the help of laboratory test,simulate on-site grouting process,according to the main structure of complete coal sample after bearing failure,pick up the complete fracture surface,manually assemble it into the theme structure of post-peak bearing strength,and put it into the standard test mold.Then,prepare different grouting materials to obtain the coupling grouting samples of standard size and specifications of post-peak broken coal sample,and calculate the size correction coefficient.3.Through the identification and analysis of stress-strain curve characteristics and numerical calculation of compressive strength of serial test,it is considered that the process characteristics of stress-strain curve of coal and rock samples strengthened with different contents of cement are very different,and the compressive strength values after strengthening are very different.The greater the injection amount of reinforcement materials,the higher the compressive strength,the better the reinforcement effect,the more obvious the brittle fracture characteristics of coal samples,and the longer the unstable fracture development stage of rock samples.The reduction degree of bearing capacity after fracture is negatively correlated with cemented reinforcement materials.Finally,the grouting material with the best ratio for Balasu Coal Mine was developed.4.Based on the results of laboratory tests and numerical simulations,it is found that the slurry diffusion radius is positively correlated with the grouting pressure.When the grouting pressure increased from 7.5 to 9 MPa,the slurry diffusion radius of the No.2water-rich coal seam increased significantly,with a growth rate of 24.9%;when the grouting pressure increased from 9 to 10 MPa,the growth rate was only 2.5%.Therefore,9MPa is determined as the optimal grouting pressure for grouting and water blocking in Balasu Coal Mine,which ensures the grouting effect under complex working conditions,and provides a theoretical basis for the design and construction parameters of grouting reinforcement for strong water-rich coal body.This thesis has 29 figures,16 tables and 64 references.