张浪. 突出煤体变形破坏过程声发射演化特征综合分析[J]. 煤炭学报, 2018, 43(S1): 130-139. DOI: 10.13225/j.cnki.jccs.2018.0269
引用本文: 张浪. 突出煤体变形破坏过程声发射演化特征综合分析[J]. 煤炭学报, 2018, 43(S1): 130-139. DOI: 10.13225/j.cnki.jccs.2018.0269
ZHANG Lang. Comprehensive analysis of acoustic emission evolution characteristics during deformation and failure process of outburst coal[J]. Journal of China Coal Society, 2018, 43(S1): 130-139. DOI: 10.13225/j.cnki.jccs.2018.0269
Citation: ZHANG Lang. Comprehensive analysis of acoustic emission evolution characteristics during deformation and failure process of outburst coal[J]. Journal of China Coal Society, 2018, 43(S1): 130-139. DOI: 10.13225/j.cnki.jccs.2018.0269

突出煤体变形破坏过程声发射演化特征综合分析

Comprehensive analysis of acoustic emission evolution characteristics during deformation and failure process of outburst coal

  • 摘要: 对阳煤新元矿3号突出煤层的原煤和型煤进行载荷控制方式下的变形破坏试验,研究不同类型煤样变形破坏过程中声发射特征及其差异。研究结果表明,煤体破裂过程经历了3个阶段:非裂纹发展阶段、裂纹的稳定发展阶段和非稳定发展阶段。原煤在裂纹的稳定发展阶段及其以后,体应变速率的增大伴随着声发射指标的增大,且体应变的突降伴随着声发射指标的激增。原煤的裂纹非稳定发展阶段出现在峰值应力之前,表现出峰后的脆性变形特征,声发射指标峰值也出现在峰值应力之前;而型煤的裂纹非稳定发展阶段出现在峰值应力以后,表现出峰后塑性流动的延性变形,声发射指标峰值也出现在峰值应力以后。原煤破裂过程中呈现出两种体应变-时间曲线形态,既有较为平滑的曲线形态,也有在裂纹的稳定发展阶段就开始出现短时突降的体应变-时间曲线形态;而型煤仅呈现出平滑的曲线形态。原煤的声发射参数与应力之间总体上呈正相关关系,且在裂纹的非稳定发展阶段或者稳定发展阶段的中期以后,声发射参数具有较高的数值;而型煤声发射参数的演化分为两个阶段,峰前的平静期和峰后的爆发期,由峰前较为稳定的低值跃升到峰后较高水平的最大值,其破坏的声发射参数具有突增性。原煤声发射强度包括平均强度和峰值强度均远大于型煤的声发射强度,这主要是原煤强度较高容易积聚较高的弹性潜能且内部结构相对破碎所致。

     

    Abstract: To study the acoustic emission characteristics and differences during the deformation and failure process of different type coal samples, the raw coal samples and briquette samples from 3 outburst coal seam in Xinyuan coal mine, Yangquan Coal Group, are compressed under the load control method. The results show that during the test, the coal samples undergo three stages: the non-crack development stage, the stable development and unstable development stage of the crack.During the stable development and unstable development stages of the crack, the acoustic emission index increases with the volumetric strain rate of the raw coal samples, and the acoustic emission index violently increases with volumetric strain sharp drop.For the raw coal samples, their unstable development stage of the crack oc-curs before the peak stress, which indicates the brittle deformation after the peak, and the peak of acoustic emission index also occurs before the peak stress. Conversely, for the briquette samples, their unstable development stage of the crack occurs after the peak stress, which indicates the ductile deformation of plastic flow after the peak, and the peak of acoustic emission index also occurs after the peak stress.Two kinds of volume strain-time curves are presented during the raw coal samples test.One is smoother curve, the other is with short-time sudden drop in the stable development stage of the crack.But for the briquette samples, there is merely smoother curve. For the raw coal samples, there is a positive correlation between the acoustic emission parameters and the stress, and the acoustic emission parameters have a higher value during the unstable development stage or after the middle stages of the stable development stage of the crack.Nevertheless, for the briquette samples, the evolution of the acoustic emission parameters can be divided into two stages, the quiet period before the peak and the outbreak period after the peak.Acoustic emission parameters rise from a relatively stable low value before the peak to the maximum value of the higher level after the peak, which indicates a sudden increase in the process of the briquette samples failure. Due to the higher strength of the raw coal samples, which can easily accumulate higher elastic potential energy, and the relatively broken internal structure, the acoustic emission strength of the raw coal samples, including the average strength and the peak strength, is far greater than that of the briquette samples.

     

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