来兴平,贾冲,胥海东,等. 急倾斜深埋巨厚煤层掘巷冲击地压前兆特征及其灾害防治[J]. 煤炭学报,2024,49(1):337−350. DOI: 10.13225/j.cnki.jccs.2023.1553
引用本文: 来兴平,贾冲,胥海东,等. 急倾斜深埋巨厚煤层掘巷冲击地压前兆特征及其灾害防治[J]. 煤炭学报,2024,49(1):337−350. DOI: 10.13225/j.cnki.jccs.2023.1553
LAI Xingping,JIA Chong,XU Haidong,et al. Precursory characteristics and disaster prevention of rock burst in roadway excavation in steeply inclined extra-thick coal seam[J]. Journal of China Coal Society,2024,49(1):337−350. DOI: 10.13225/j.cnki.jccs.2023.1553
Citation: LAI Xingping,JIA Chong,XU Haidong,et al. Precursory characteristics and disaster prevention of rock burst in roadway excavation in steeply inclined extra-thick coal seam[J]. Journal of China Coal Society,2024,49(1):337−350. DOI: 10.13225/j.cnki.jccs.2023.1553

急倾斜深埋巨厚煤层掘巷冲击地压前兆特征及其灾害防治

Precursory characteristics and disaster prevention of rock burst in roadway excavation in steeply inclined extra-thick coal seam

  • 摘要: 随着冲击地压矿井逐渐向深开采,其巷道掘进伴随的冲击显现愈发强烈。针对巷道掘进过程中的冲击地压有效防治问题,以新疆乌东煤矿急倾斜煤层矿井为例,运用微震监测对巷道掘进的冲击地压时空前兆特征加以分析。结合巷道掘进的应力与能量变化数值模拟分析,揭示巷道掘进的冲击地压发生机理,提出急倾斜巨厚煤层巷道冲击地压防治策略,并完成现场工程实践验证。研究结果表明:急倾斜巨厚煤层巷道掘进的冲击地压发生前第2~5天出现微震总能量极低值,或存在至少4 d的能量潜伏期;冲击地压发生前5 d普遍存在3 d以上的最大能量占比高频波动期。冲击地压发生前存在明显缺震现象,发生位置集中分布在距离掘进工作面较近的微震能量极小值区间范围内,或位于微震能量极值区间附近的微震频次极小值区间范围内,且冲击地压事件位于冲击变形能指数较高区域。急倾斜巨厚煤层水平分段综放开采的坚硬覆岩结构不易破断,使得巷道掘进存在上水平采空区两侧“双翼型”应力集中,掘进工作面前方与巷道底部受顶底板岩层相互挤压的应力集中分布且能量积聚显著,随着巷道掘进深度增加其应力集中与能量积聚进一步增强,容易诱发冲击地压等动力灾害。综合分析形成急倾斜巨厚煤层巷道掘进的工作面爆破卸压、巷道钻孔卸压与补强支护、复杂区域架蓬的冲击地压防治策略。结合冲击地压时空前兆异常为及时加强卸压力度提供时机。通过工作面与巷道卸压使得掘进期间未发生单日累计1×105 J以上微震能量,在对支护优化调整与复杂区域重点防护后,巷道掘进日均微震能量降至2.2 kJ,其1 kJ以上微震事件占比下降且巷道断面整体平整。研究结果为急倾斜巨厚煤层巷道安全掘进提供了科学依据。

     

    Abstract: With the gradual coal mining of deep rock burst mine, the impact accompanying roadway excavation becomes more and more intense. Aiming at the problem of effective prevention and control of rock burst in roadway excavation, taking the steep seam mine in the Wudong Coal Mine as an example, the temporal and spatial precursor characteristics of rock burst in roadway excavation were analyzed by microseismic monitoring. Combined with the numerical simulation analysis of stress and energy changes in roadway excavation, the mechanism of rock burst in roadway excavation was revealed, and the prevention and control strategy of rock burst in steeply inclined extra-thick coal seam roadway was put forward, which was verified by field engineering practice. The results show that the total energy of microseisms is extremely low for 2−5 days or there is an energy latency of at least 4 days before the rock burst occurs due to roadway excavation in steeply inclined extra-thick coal seam. Within 5 days before rock burst occurs, there is a high-frequency fluctuation period of maximum energy ratio for more than 3 days. There is an obvious lack of earthquake before the rock burst occurs, and the occurrence position is concentrated in the range of minimum value of microseismic energy near the heading face, or in the range of minimum value of microseismic frequency near the extreme value of microseismic energy, and the rock burst event is located in the area with high impact deformation energy index. The hard overburden structure of horizontal sublevel fully mechanized caving mining in steeply inclined extra-thick coal seam is not easy to break, which makes the stress concentration on both sides of upper horizontal goaf exist in roadway excavation. The stress between the front of the heading face and the bottom of the roadway squeezed by the roof and floor strata is concentrated and the energy accumulation is remarkable. With the increase of the heading depth of the roadway, the stress concentration and energy accumulation are further enhanced, which is easy to induce dynamic disasters such as rock burst. The prevention and control strategies of rock burst was established through comprehensive analysis, which consist of face blasting pressure relief, roadway drilling pressure relief and reinforcement support, and scaffolding in complex areas. Combined with the temporal and spatial precursory anomalies of rock burst, it provides an opportunity to strengthen the unloading pressure in time. Through the pressure relief of working face and roadway, the accumulated microseismic energy of more than 1×105 J per day did not occur during the excavation. After the support was optimized and the complex area was protected, the daily average microseismic energy of roadway excavation decreased to 2.2 kJ, and the proportion of microseismic events above 1 kJ decreased, and the overall section of roadway was flat.

     

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