组合断层煤层大能量矿震的前兆信息特征规律研究

Research on Characteristic Law of Precursor Information of Large Energy Mining Earthquake in Combined Fault Coal Seam

屯宝煤矿WII02040501综放工作面回采期间,组合断层区域微震大能量事件频发且异常集中,为精准识别组合断层下冲击地压前兆预警信息,统计分析了工作面回采速度偏差值下有效预警时间窗范围,选取微震能量偏差值D_(e)、微震频次偏差值D_(f)为断层区冲击前兆异常指标,并融合断层总面积指标A(t)对WII02040501工作面进行综合预警。研究表明:工作面的微震能量和频次随断层距离接近而上升,进入断层区后指标达到峰值并保持高值异常,回采过断层后指标逐步降至正常水平,表明工作面微震事件受断层影响显著;大能量矿震发生前,D_(e)会先缓慢降低,然后突升,变化量大于70,大能量矿震当日能量偏差值均超过100;D_(f)则呈现先升高后降低的趋势,大能量矿震前3~5 d,频次偏差值出现低点临界值,临界值为0.47;A(t)在大能量前8 d内略微下降后迅速增大,表明组合断层受采动应力影响,导致断层活化,诱发了大能量矿震事件。

Frequent and anomalous concentration of microseismic large-energy events in the combined fault area during mining in the Tunbao coal mine WII02040501 fully mechanized caving face.In order to accurately identify the precursory warning information of rock burst under the combined faults,the effective warning time window range under the deviation value of the mining speed of the working face is statistically analyzed.The microseismic energy deviation value D_(e) and the deviation value of microseismic frequency D_(f) are selected as the precursory anomaly indexes of the fault zone,and the total area index of the fault A(t)is integrated to comprehensively warn the WII02040501 working face.The results show that the microseismic energy and frequency gradually increase when approaching the fault,reach the peak after entering the fault and maintain the anomaly in the high value range,and gradually decrease to the normal range after leaving the fault,indicating that the fault development of the working face causes the microseismic anomaly.Before the occurrence of the large energy mine earthquake,the D_(e) will first decrease slowly,then rise abruptly,and the variation is greater than 70,while the energy deviation value of the large energy mine earthquake on the day is more than 100;the D_(f) showed a trend of increasing first and then decreasing.Three to five days prior to a large energy mine earthquake,the frequency deviation values have a low point critical value of 0.47;the A(t)decreases slightly within 8 days before the large energy and then increases rapidly,indicating that the combined fault is affected by the mining stress,which further leads to the activation of the fault and induces the large energy mine earthquake event.