Safety Technology Center of Shanxi Coal Mine Safety Supervision Bureau
School of Safety and Emergency Management Engineering, Taiyuan University of Technology

为探究煤体在冷热冲击影响下的渗流规律及力学损伤机制,利用高低温系统、三轴渗流系统,对饱水煤样进行不同温度条件下冲击试验,基于声发射、金相显微图像技术分别对饱水煤样经冷热冲击处理后结构损伤演化进行定位、定量分析。研究结果表明:经不同冷热温度冲击,煤样渗透率均有增加,增幅为20.59%~253.26%,但不同孔隙压力下煤体的渗透率增幅随温度梯度并非正相关,而是呈现低—高—低的趋势;在温度冲击下饱水煤体在热应力及水冰相变产生冻胀力作用下内部结构损伤显著;冷热冲击过程中,温度梯度越大,孔裂隙扩展量越大,煤体结构劣化更为显著;冷热冲击对煤体细观损伤较为复杂,新生成主裂隙呈“S”形分布,对煤层致裂效果显著。

In order to explore the coal seepage law and damage mechanism under the influence of cold and thermal shock, high and low temperature system and triaxial seepage system were used to conduct impact tests on water-saturated coal samples under different temperature conditions. The structural damage evolution of water-saturated coal samples after cold and thermal shock treatment was located and quantitatively analyzed. The results show that the permeability of coal samples increased by different cold and thermal shock temperatures, and the increase range is 20. 59% to 253. 26%. However, the permeability increase of coal body under different pore pressures is not positively correlated with temperature gradient, but shows a low-high-low trend. Under temperature shock, the thermal stress and water-ice phase transition of water-saturated coal body produce frost heaving force. The damage to the lower internal structure is significant. In the process of cold and thermal shock, the greater the temperature gradient, the greater the expansion of pores and fractures, and the more significant deterioration of coal structure. The mesoscopic damage to coal body caused by cold and thermal shock is relatively complex, and the newly formed main fractures are distributed in an “S” shape, which has a significant effect on coal seam cracking.

王珂,戎彦龙,郭志. 冷热冲击条件下饱水煤样渗流及力学特性研究[J]. 矿业安全与环保,2023,50(4):42-46.

WANG Ke,RONG Yanlong,GUO Zhi. Study on seepage and mechanical properties of water-saturated coal sample under the condition of cold and thermal shock[J]. Mining Safety & Environmental Protection,2023,50(4):42-46.