Numerical Simulation Of The Coal Seam Roof Fracture Zone In -950 Level,Donghuantuo Coal Mine,Kailuan

Water hazard in Donghuantuo Coal Mine is serious.The thickness and distance of No.8and No.9 coal seams are unevenly distributed in space.Some areas belong to close seams.Coal seams are threatened by roof water hazard.It is of great significance to predict the development height of water-conducting fracture zone in No.8 and No.9 coal seams.Taking No.8 and 9 coal seams-950 of donghuantuo in Kailuan as the research object,the geological data of the study area are collected,and the spatial occurrence conditions such as thickness,dip angle and spacing of coal seams 8 and 9 are analyzed.The height of water conduction crack zone,its spatial distribution and influencing factors are estimated by using empirical formula and formula in specifications.Contrast strata to design models with control variable method.The development height and influencing factors of water conduction crack zone after model excavation are analyzed,and the discrimination conditions of close coal seams are summarized.The results show that No.8 and No.9 coal seams are moderately thick and gently inclined seams,and the thickness distribution shows the regularity of thickness between two ends,with spacing of 1.05-16.99 m,small spacing between two ends and large spacing,and some areas are close seams.The height of water conduction crack zone in No.8 coal seams calculated by empirical formula is 22.14～55.44 m,and the height of water conduction crack zone in No.8 and No.9 coal seams is 36.68～91.36 m above No.8 coal seams.Within a certain range,the difference between the height of No.8 seam and that of comprehensive water conduction crack zone is inversely proportional to the spacing between seams and that of No.9 seam.The strata structure between No.8 and No.9 coal seams at 950 level is soft-hardsoft and soft-hard.When the water conduction fissure zone height of No.8 coal seams is 64 m,the mining height of No.8 coal seams is 3.6m,and the mining height of No.9 coal seams is3.7m,the strata structure is soft-hard-soft and soft-hard respectively.When the spacing between coal seams is less than 16 m and 14 m,belongs to close-distance coal seams..Figure 96;Table 22;Reference 78...