Study on coal pillar position and surrounding rock control technology under strong dynamic pressure and coal body degradation
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Abstract
Aiming at serious deterioration of coal mechanical properties, large deformation and the control difficulty of surrounding rock deformation under the strong dynamic pressure, by the means of theoretical analysis, numerical simulation and field test, the control technology are systematically studied.The results show that there are many groups of broken zones in the coal pillar side, the average uniaxial compressive strength of coal decreases by 24.25%, the anchoring force of anchor cable decreases by 27.2%-42.7%, the bearing capacity of coal pillar side decreases greatly and becomes weak side under the influence of strong dynamic pressure.The compression and transverse movement of weak side induce deformation and instability of roadway by under strong dynamic pressure.According to the analysis results of roadway deformation and failure, the reasonable coal pillar size was determined to be 10 m through the numerical simulation analysis, and the roadway control principles were put forward including strong support of weak side, performance matching, high prestress level balance and mutual supplement.The combined support scheme of steel bar and anchor cable was designed and carried out in the underground industrial test.The engineering practice shows that the reasonable roadway layout and new support scheme can effectively control the large deformation of roadway, reduce the convergence rate of roadway section by 33.7%, and the anchor cable and steel bar are not broken, which can meet the requirements of normal production.
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