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以某矿综放工作面开采过程为背景,利用微震监测技术进行现场监测,并借助有限差分FLAC~(3D)进行数值分析,研究在采动应力场不断变化过程中底板岩体微震破裂事件的时空演化规律,揭示煤层采动条件下潜在导水通道的孕育、发展和贯通过程.微震监测结果表明:微震事件数一定程度上反映了开采扰动对底板岩体破坏程度的影响;采煤期间,回采工作面附近微震事件呈现密集分布,底板岩体采动破坏严重,底板破裂深度达15m.数值分析表明:由于煤层采动导致采场周围应力重分布,工作面前方应力增高,采空区下方应力降低,底板岩体随工作面回采经历了应力集中、释放并最终破坏;底板塑性破坏区深度达14m.
Taking the mining process of a fully mechanized top coal caving mining face as a background, on-site monitoring was made by using microseismic monitoring technology. The numerical analysis was carried out by means of finite difference FLAC 3D to study the microseismic rupture during the continuous changing of mining stress field Time and space evolution to reveal the process of breeding, development and penetration of potential aqueducts under mining conditions.The microseismic monitoring results show that the number of microseismic events reflects the influence of mining disturbance on the failure degree of floor rock mass to a certain extent; during coal mining , The microseismic events near the mining face show a dense distribution, the floor rock mass is seriously damaged and the bottom plate ruptures to a depth of 15m. Numerical analysis shows that due to the stress redistribution around the stope and the stress in front of the working face, The stress in the lower part decreases, and the bottom rock mass undergoes stress concentration with the working face recovery and eventually destroys. The depth of the plastic damage zone in the bottom plate reaches 14m.