急倾斜坚硬岩柱动态破裂“声–热”演化特征试验

ACOUSTIC EMISSION AND TEMPERATURE VARIATION IN FAILURE PROCESS OF HARD ROCK PILLARS SANDWICHED BETWEEN THICK COAL SEAMS OF EXTREMELY STEEP

急倾斜坚硬岩柱稳定性预测对科学采矿具有重要意义。以乌鲁木齐矿区急倾斜特厚煤层安全开采为背景,基于平面组合加载试验平台,构建急倾斜坚硬岩柱动态破裂"声–热"演化特征模型试验,采用岩石破裂声发射和红外热像综合监测方法,揭示开采扰动作用下岩柱破裂过程中的声发射与温度演化规律。研究表明:坚硬岩柱破裂过程中红外热像呈现温度辐射区(可分为低温边界区、中温过渡区和高温中心区);岩柱破裂经历弹性变形、微破裂至破裂失稳过程,该过程中温度辐射区温度逐渐降低,AE能率呈持续性增长;动态破裂"声–热"演化实质为热弹效应和摩擦热效应。这对急倾斜特厚煤层安全开采具有科学意义。

Stability analysis of hard rock pillars is significant for hazards prediction to the mining of thick coal seams of extremely steep. Modeling the hard and extremely steep rock pillar experimentally was accomplished with the composite-loading facility. The temperature and acoustic emission(AE) parameters were recorded with the infrared thermal instruments and AE sensors. Areas of heat radiation on the surface of rock pillar were found to emerge with a low temperature area near the boundary,a middle temperature area between boundaries,and a high temperature area across the boundary. The hard rock pillars experienced different stages including the elastic deformation,the micro ruptures and the fracturing instability. The accumulation ratio of AE energy was increased continuously and the temperature in the radiation area was decreased gradually. The reasons of AE and temperature variation during the hard rock pillar failure were the thermo-elastic transformation effect and thermo-friction effect.