| In this paper,the engineering background of excessive fault mining at the 1300 working face of Yuncheng Coal Mine in Shandong Province is used.UDEC and FLAC3D numerical simulation software is used to simulate the actual engineering problems of real site pressure and pressure disasters on the site.The effects of rock migration and mining stress distribution,comprehensive knowledge of fields such as mine pressure and rock formation control,mining science,and elastoplastic mechanics,yield the following conclusions:(1)The numerical simulation software FLAC3D was used to study that:under the condition of a fault A70°,the fault wall advances towards the fault.The vertical stress of the coal body in front of the working face increases first and then decreases as the fault coal pillar decreases.When the distance from the fault is 15m?0m,a large amount of coal in front of the working face will undergo plastic failure,and the stress will be as low as the original rock stress,or even less than the original rock stress;keep the A70°fault unchanged in multiple faults,and change the right fault angle to B50°,B55°,B60°,B65° and B70°,with the increase of the fault dip angle on the right,the vertical stress stress drop of the coal body in front of the working face is significantly reduced,and the smaller the dip angle of the right fault,the greater the stress drop and the greater the fault dip angle,The more obvious the fault blocking effect;keep the A3m fault unchanged in multiple faults,and change the width of the right fault zone to B3m,B4m,B5m1B6m,and B7m.It can be seen that the vertical stress drop in front of the working face decreases with the increase of the fault zone width the greater the width of the fault zone,the greater the fault blocking effect.(2)Using numerical simulation software UDEC,it is found that in the case of a fault A70°,the fault is pushed to the fault and the mining is carried out.When the working surface is advanced to 30m away from the A700 fault,the working face is not affected by the fault,and the mining is carried out.The overburden structure in the area is normal,showing a "trapezoidal" overburden structure,and the“three belts”of the overlying strata in the goaf are obvious.After advancing to the fault 30m,entering the fault-affected area,the“three-band" feature of the overlying strata in the goaf gradually disappears,and the spatial overburden structure changes from "trapezoid"to "triangle";when the working surface pushes through the A70°fault,In the lower face of the B fault,the greater the fault dip angle,the more severe the overburden movement.The overlying rock over the middle goaf of the two faults will be slid and sunk along the fault plane.When the lower plate works for fault mining,The high-level fault is firstly unstable and activated,and the larger the dip angle is,the more obvious it is.When the dip angle of the fault is small,the relative slip of the upper and lower discs is small,and the barrier effect of the fault is not obvious.The larger the dip angle of the fault,the larger the subsidence of the lower plate of the fault along the fault plane,the smaller the amount of slip along the fault plane on the upper fault,the less affected,and the greater the barrier effect of the fault.(3)Combined with the micro-seismic data of the 1300 working face in Yucheng Coal Mine,the 1300 working surface is in the area where the mining is highly developed to the fault structure.The micro-seismic energy events occur frequently in the working face,and the closer to the fault,the closer the fault is to the fault.The more frequent the microseismic event and the higher the energy level,the more the number of microseismic events and the energy level are larger than the single fault affected area in the multi-fault stacking complex influence area.And the small microseismic event has the tendency to accumulate energy for the large microseismic event.The large energy event has a transient suddenness,which occurs mostly in the working surface close to the fault. |
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