煤体电荷感应信号评价冲击危险性试验研究

为完善冲击地压矿井的冲击危险性评价方法,提高冲击危险性预测的准确率,应用自主研制的煤岩电荷监测系统,选择典型冲击地压矿井的煤样,开展了煤体单轴压缩冲击危险性测试与电荷感应监测试验研究。基于冲击地压扰动响应失稳理论,将应变软化阶段产生的电荷信号变化作为预测冲击地压发生的前兆信息,得到了煤体冲击危险性指标的临界软化系数Kρ、临界应力系数Kp及其冲击危险的等级分类标准,分析了煤体电荷感应信号的电荷事件数CSJ和电荷事件的平均幅值CFZ参量与冲击危险性指标Kρ和Kp之间的量化关系。结果表明:煤样破裂应力峰后,冲击倾向性K与电荷事件数CSJ呈指数递减关系,与CFZ呈指数递增关系;随着Kρ或Kp的增大,煤样应力峰后CSJ呈幂函数关系递增,应力峰后电荷平均幅值CFZ呈一次函数关系递减,以此可预测煤体的冲击危险程度,最后得到了河南某矿煤层冲击危险性的应力峰后冲击危险等级的CSJ和CFZ判据与划分标准。煤体冲击危险性电荷感应信号评价方法为冲击地压矿井冲击危险性评价提供了一种新的方向,对现场煤层冲击危险性评价具有指导作用,但也还需要开展大量现场试验对其进行不断修正和完善。

Experimental study and the evaluation of the burst risk of the induction charge signal of the coal body

The given paper is to present the author’s own selfdeveloped charge monitoring system for coal and rock burst risk under the uniaxial compression and the charge induction signal with the chosen typical rock burst coal samples so as to improve the evaluation method and the prediction accuracy of the rock burst risk.And,then,to improve the evaluation method and the prediction accuracy of the rock burst risk,the said paper has taken the change of the charge signal generated in the strain softening stage as the precursory information to predict the occurrence of the rock bursts and the rock burst risk indexes based on the instability theory of disturbance response to the said burst,including the critical softening coefficient Kρ and the critical stress coefficient Kp,as well as the classification standard of the rock burst risk grade that can be forecast and gained.What is more,the quantitative relationship between the charge induction signal parameters of the charge events CSJ and the average amplitude of the charge events CFZ have also be analyzed and confirmed along with the rock burst risk indexes Kρand Kp.The results of the above research findings prove that there lies an exponential decreasing relationship between the rock burst tendencies K and CSJ,as well as an exponentially increasing relationship between the rock burst tendencies K and CFZ due to the rupture of the stress peak of the coal sample.On the other hand,with the increase of Kρor Kp,the number of charge events CSJ after the stress peak of the coal sample also tends to increase in accordance with the power-law function,whereas the charge average amplitude CFZ tends to decrease in accordance with a linear function as is followed by the stress peak,which can help to forecast the risk extent of the rock burst.And the CSJ and CFZ criteria and classification standard of the rock burst risk grades for the coal seam impact risk next to the stress peak can also be gained in a certain coal mine of Henan.Thus,the charge induction signal evaluation method of the rock burst risk can also provide us with a new criteria for the rock burst risk assessment in such rock burst mines.And,so,it can be expected that an instructive role in the said field can be deduced from the coal seam rock burst risk assessment,though it remains necessary to conduct a great number of field tests to modify and optimize it further.