基于冲击启动过程的近场围岩冲击危险性电磁波CT评估方法

Electromagnetic wave CT evaluation method for rock burst hazard in near field based on rock burst start-up process

近年来,随着开采深度和强度的逐渐增大,冲击地压灾害发生频率逐年升高,严重威胁矿井的安全生产。针对目前基于现场实测的冲击危险性评价方法仅从能量聚集角度进行危险性判别,导致评价结果不能反映现场全部冲击危险情况的问题,考虑了冲击启动过程经历的"能量释放→能量传递→冲击显现"3个阶段,分析了基于冲击启动过程的冲击危险性评估原理,通过理论研究,构建了包括能量集中指数、屈服接近指数、能量传递衰减指数和支护损伤指数等4个指标,设定了各指标的权重,包括根据各指标量值差异程度设定的属性权重,以及根据各指标危险等级设定的等级权重;由此,以电磁波CT探测系统为平台,建立了能够划分近场围岩冲击危险区域及危险等级的电磁波CT评估方法,并将该方法编程实现。应用此方法对亭南煤矿207工作面现场实测数据进行处理,发现区段煤柱内布置巷道大幅升高了相邻煤柱区的应力集中程度及支护损伤程度,进而增大了相邻煤柱区的冲击危险性。通过钻屑法验证了基于冲击启动过程的冲击危险性评估方法的有效性。该方法依据冲击启动过程将评估体系细化,能够有效提升对冲击危险区域及危险等级的辨识度,为巷道冲击地压治理提供了更为准确的依据,尤其能为煤柱区冲击地压防治提供借鉴。

In recent years,with the gradual increase of mining depth and intensity,the frequency of rock burst disaster increases year by year,which seriously threatens the safety of mine production.Currently,the risk assessment method is based on field measurement only accounting for energy accumulation,which leads to the failure of the evaluation results to reflect all rock burst hazards in the field.In this study,three stages of energy release,energy transfer and shock appearance were considered. On the basis of the electromagnetic wave CT detection platform,through theoretical research,a rock burst start-up probability of the four indexes was proposed,including the fusion energy concentration index,the support damage index,the yield close index and the energy transfer attenuation index,by combining the yield proximity and unloading coupling theory with the impact pressure theory. Also,the weight of each index was determined,including attribute weight set according to the difference degree of each index value,and grade weight set according to the risk level of each index.A multi-factor comprehensive evaluation model for rock burst hazard was established,and then a multi-factor evaluation method for near-field surrounding rock burst hazard was established,and the method was implemented by programming.In the 207 return airway of Tingnan Mine in China,it was found that the arrangement of roadway in the section of coal pillar greatly increased the stress concentration of the coal pillar area,which leads to the higher degree of support damage and the larger plastic zone,and has a higher impact risk.Using this method,the field measured data of 207 working face in Tingnan Coal Mine were processed,which was found that the distribution of roadway in the section of coal pillar increased the degree of stress concentration in the coal pillar area,and leaded to the higher degree of support damage.The larger plastic zone range,and the higher rock burst hazard.The drilling cuttings method was used to verify the effectiveness of the impact risk assessment method based on impact start-up process.Compared to the rock burst hazard assessment method of surrounding rock in the past,the rock burst startup probability evaluation method proposed comprehensively considered the influence of multiple factors,improved the identification degree of the rock burst hazard area,and provided a more accurate basis for the roadway rock burst control.Especially,for the coal pillar area,it is of significance in application.