| In this paper,Based on the actual engineering problems of mine pressure and anti-shock during the face mining of Yangliu Mine and Liangbaosi Mine,using field measurement,theoretical analysis,numerical simulation and other research methods,comprehensive elastoplastic mechanics,mining and other fields Knowledge,in-depth and systematic research on the subject,and the main research results are as follows:Using the finite element numerical simulation software FLAC3D study,the following conclusions are drawn:The working face only has L70°(L70°indicates 70° left fault)fault.After crossing the fault,the vertical stress of the coal in front of the working face is affected by the fault activation,and the strong influence range of the fault is 50m,which affects the front of the working face 90m,the maximum vertical stress concentration is 35.43MPa due to fault;there are two faults on the working face,L70°and R70°(R70°means right fault 70°)fault.When the distance between L70° and R70° is 100m,the working face is mined in the middle of the two faults.The influence of the two faults is superimposed,the peak of the vertical stress concentration is 36.28 MPa,the fault spacing is reduced to 70 m,the influence of the two faults is intensified,the maximum stress concentration peak is 37.99 MPa,the fault spacing is 50m minimum,the two faults have the greatest influence,and the stress concentration peak is 38.60 MPa.The degree of stress concentration of coal increases with the decrease of fault spacing.Regardless of the distance between L70° and R70°,when the working face has just passed the L70° fault,the mining induces fault activation,and the overburden movement is strong.The coals at both ends of the working face near the fault are subjected to large loads and stress concentration.The working face is close to the R70° fault,and the coal bodies on both sides are subjected to load increase and become the main bearing area of the load.Using the finite element numerical simulation software FLAC3D study,the following conclusions are drawn:Different fault dip,the working face is mined in the middle of the two faults,the working face has just been pushed through the L70° fault 20m,the fault activation is induced to mining,and the peak of coal verrtical stress in front of the working face is slightly increased;with the working face continuing to advance into the area of the right fault,the vertical stress peak before the instability of the coal pillar between the working face and the right fault increases with the increase of the dip of the right fault;the elastic energy released from the steady state to the complete plastic failure is increased with the dip of the right fault.The proportion increases,and the simulation data indicates that the possibility of the rock burst at the working face and the damage increase with the increase of the dip of the fault.At the same time,the load on the two sides of the working face is obviously concentrated in the process of pushing the left fault and the right fault near the working face,and the vertical stress concentration is large,which is the area where the rock burst occurs frequently.Using the discrete element numerical simulation software UDEC,the following conclusions are drawn:The working face is located in the middle of the L70°-R45° model and L70°-R55°model.The working face is advanced from the left fault to the right fault.The 26m,42m,78m and 116m rock strata over the top of the working face in the L70°-R45° model and L70°-R55°model are not activation slip occurred at the fault.When the working face is mined in the middle of the L70°-R65° model and L70°-R75° model,the fault has a tendency to activate when the working face is 30m from the R65°fault,but the R75°fault is 40m.The possibility and the amount of the rock slip at the fault increase with the increase of the right fault dip.When the L70°-R75° model is mined,the rock slip at different strata is higher than that of the L70°-R65°model at all stages. |
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