Stress distribution in fault zone and surrounding rock control in upward fully-mechanized top coal caving face of extra thick coal seam
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Graphical Abstract
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Abstract
In the view of passing the fault in upward fully-mechanized caving face of extra thick coal seam, the spalling and roof falling was difficult to be controlled. Based on geological conditions of No.10301 working face in Jining No.2 Coal Mine, reasonable path for passing fault was provided according to theoretical analysis and the stress and plastic evolution law were obtained using numerical simulation.The research results showed that it was more reasonable to go through Fault F49 in the di stance of 15 m advanced cutting floor and the 11° advance broke angle. When the working face was advanced 35 m away from the fault, the peak of advanced abutment pressure became increasingly large and moved toward the coal wall side, which led to coal wall spalling.Meanwhile, the fault activation degree was gradually strengthe ned.The main roof's advanced vertical stress peak value increased and periodic weighting length decreased, which meant that the roof was hard to be controlled.When the working face was propelled 15 m away from the fault, upper strata plastic zone started to spread to the fault and until the fault was exposed, the fault was covered b y plastic zone .After that, technical measurements were presented, such as strengthening coal caving control, roof management, to ensure the safety during the No.103 01 working face passing the fault.
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