远距离煤层群开采下山巷道震动显现成因

The cause of quake behavior in dip roadway under long distance coal seam group

为探索远距离煤层群开采过程下山巷道异常震动显现的成因,基于高精度微震监测和现场调查,应用岩体破裂规律分析预测工具MapRAS分析矿震原因,用离散元数值试验工具UDEC分析巷道围岩动力响应规律,得到:工业广场保护煤柱及己二下山非采动区域频发矿震是工作面采动顶板关键层运移对煤柱边缘强剪应力带作用的结果,其作用的效应与开采深度呈正比,与采动影响距离呈反比。震动显现多发生在非采动直接影响的己二下山巷道围岩,这种异常现象与己组煤岩物理力学性质、3组工作面复合压力拱脚动态加卸载作用和矿震动力源影响距离有关。根据矿震震级、震动显现程度和数值试验岩体质点振动速率,提出了与现场实际基本相符的巷道围岩震动显现危险等级判据指标。使用微震频次,用傅里叶周期法反演的图像,可较敏感反映顶板关键层周期破断规律和相邻区段岩体动力响应的相关性。用UDEC数值试验,较好地揭示了工作面采动对己二下山围岩的影响规律。

To explore the mechanism of unusual quake behavior in dip roadway during mining long distance coal seam group,on the basis of high-precision micro-seismic monitoring data and field investigation, the anthors analyzed the reasons of mining-induced quake by MapRAS which was used to analysis and forecast the laws of rockmass breaking, and the dynamic response laws of roadway surrounding rock was analyzed by distinct element method UDEC. The fol- lowing conclusions were gotten. Frequent mine earthquakes in industrial square protective coal pillar and non-mining area of F-2 dip roadway are the results that key roof stratum movements act on strong shear stress zones of edge coal pillar during working face mining and the effects are directly proportional to the mining depth and inversely proportional to mining influence distance. The quake behavior often occurred in F-2 dip roadway which is non-mining direct influent area and the unusual phenomena are related to the physical and mechanical properties of F group coal, composite pressure arch springing dynamic loading and unloading effects during mining the three groups of working face and the effect distance of mine earthquake dynamic source. The authors proposed the surrounding rock of roadway quake behavior hazard level criterion and index according to the quake magnitude, quake behavior level and rock mass parti- cle vibration velocity from numerical experimentation and the criterion basically conforms to the facts. The authors got images by inversion using micro-quake frequency and Fourier cycle method which sensitively reflect the periodic breakage laws of roof key stratum and the correlation of rock dynamic response in adjacent sections. Simulation test by UDEC reveals the effect laws of working face mining on the surrounding rock of F-2 dip roadway.