基于响应能量和无响应时间的冲击危险性 动态评价技术
Dynamic evaluation technology of rock burst based on response energy and non-response time
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摘要: 煤岩冲击危险性评价的研究在煤矿安全生产领域引起广泛关注,已有多种静态评价方法指 导现场防冲工作。 一方面,对于冲击地压的致灾机理和影响因素目前尚未完全掌握;另一方面,伴 随着开采活动,煤岩冲击危险性是动态变化的,因此静态评价方法不足以解决井下煤岩冲击危险性 评价的问题。 而基于现场监测的冲击危险性动态评价技术对于井下安全生产活动具有更强的参考 性。 依据统计损伤力学原理,对煤岩受载条件下的能量演化行为进行分析,发现累积能量释放速率 对时间的响应具有临界敏感性,即在煤岩临近灾变时,累积能量释放速率会激增。 此外,依据统计 学原理,复杂系统处于正常状态(无危险性)的行为应该占据较大概率,非正常状态(有危险性)的 行为应该占据较小概率,故某一时刻系统行为偏离正常状态的程度实际上反映了其自身所处危险 状态的变化。 基于以上原理,初步建立了以响应能量异常系数和无响应时间异常系数为指标的冲 击危险性动态评价的微震技术,对短期预警或临震预警展开尝试。 最后在典型冲击地压矿井已有 微震数据基础上,进行了现场验证。 研究结果表明,微震累积能量释放速率可直接反映煤岩所处冲 击危险状态;缺震时间频次分布规律满足正偏态分布;在此基础上构建的两个异常系数指标相互结 合能够实现对现场冲击危险性的实时连续评价;基于统计学原理,随着开采活动的进行,对冲击危 险性指标的阈值进行动态修正,保证动态评价结果更为灵敏、准确,这一思想可应用于其他动态评 价技术中。Abstract: The research on the evaluation of rock burst hazard has attracted extensive attention in the field of safe pro- duction in mines and many static evaluation methods have been proposed to guide the control of rock burst. On the one hand,the mechanism and influencing factors of rock burst are not yet fully understood;on the other hand,the hazard is dynamically changed along with mining activities,so the static evaluation methods are not enough to solve this prob- lem. The dynamic evaluation technology based on field monitoring has a stronger reference for safe production in mines. According to the principle of statistic damage mechanics,the energy evolution behavior of coal rock under load- ing conditions is analyzed. It is found that the cumulative energy release rate has a critical sensitivity to the response of time,that is,the cumulative energy release rate will increase sharply when coal rock is approaching catastrophe. In ad- dition,according to the statistical principle,the behavior of a complex system in a normal state (no hazard) should oc- cupy a large probability,and the behavior in an abnormal state (hazardous) should occupy a small probability,so the deviation from the normal state at a certain moment actually reflects the change of its dangerous state. Based on the above,a microseismic technology for the dynamic evaluation of rock burst hazard is preliminarily established,which takes the response energy anomaly coefficient and the non-response time anomaly coefficient as indicators. It is an at- tempt to carry out short-term or imminent shock early warning. Finally,on the basis of microseismic data of a typical rock burst mine,field verification is carried out. The results show that the microseismic cumulative energy release rate could directly reflect the dangerous state of coal rock. The frequency distribution law of microseism calm time satisfies positive skew distribution. The combination of two indicators constructed on this basis can realize the real-time and continuous evaluation of the rock burst hazard. With the development of mining activities,the threshold of indicators should be dynamically revised on the basis of statistical principle to ensure that the results of evaluation are more sen- sitive and accurate. This study can be applied to other dynamic evaluation methods.