冲击倾向性煤体破坏过程声热效应的试验研究

EXPERIMENTAL STUDY ON ACOUSTIC AND THERMAL INFRARED CHARACTERISTICS OF BUMP-PRONE COAL

介绍自行设计的多系统、同步监测试验机构,并对冲击倾向性煤体分别进行单向加载和循环加载破坏试验。利用系统所具有的红外热像、声发射、应变等监测方式,分析两种加载条件下,冲击倾向性煤体破坏过程的声、热效应及破坏前的异常信息特征。对比研究不同监测方式下,冲击倾向性煤体中同一破坏事件的响应速度以及各自响应的灵敏度;获得冲击倾向性煤体的固有物理力学特性,并发现强冲击倾向性和非冲击倾向性煤体单轴压缩时的最终破坏前兆点分别为0.9和0.7个荷载强度比,也说明强冲击倾向性煤体的失稳破坏更突然、更难于预测。

The acoustic and thermal infrared（TIR） characteristics of bump-prone coal are briefly described with different loading tests. The experimental system is designed, which is composed of the TIR observation system, the stress and strain measurement system and the acoustic emission monitoring system. It can be used to achieve different kinds of forewarning messages before the failure of rock or coal samples. The uniaxial compression loading test and the cyclic loading test are carried out to observe the features of TIR, acoustic emission and strain forewarning messages. Moreover, the response speed and the sensitivity of different monitoring systems to the cracking events in the samples are also studied under different loading conditions; and the physico-mechanical characteristics of bump-prone coal are obtained. The statistical investigation on the forewarning stress points is conducted based on the TIR images, infrared radiation temperature, acoustic emission and strain data. The analytical results show that the stress of ninety percent of strength should be regarded as the stress-caution-point for the failure of bump prone coal, which is much higher than the stress of seventy percent of strength as the stress-caution-point for the general coal samples. So it is more difficult to forecast the failure of the bump-pone coal under different loading conditions.