煤与瓦斯突出过程中煤层及巷道温度时空演化规律

    Spatial-temporal evolution law of temperature in coal seam and roadway during coal and gas outburst

    • 摘要: 利用自主研制的多功能煤与瓦斯突出模拟试验系统,开展了不同瓦斯压力条件下煤与瓦斯突出模拟试验,对突出过程中煤层和巷道温度进行了全程监测。分析结果表明:①突出发生后,煤层瓦斯压力快速下降至大气压,煤层温度演化具有一定的滞后性,主要受控于吸附瓦斯的解吸和游离瓦斯的膨胀,呈现急速下降→快速升高→缓慢变化3阶段演化特征,吸附瓦斯压力2.0、0.85、0.35 MPa条件下,煤层温度下降量峰值分别为0.56、0.23、0.11 ℃,平均下降速率分别为0.042、0.015、0.008 ℃/s,即瓦斯压力越高,煤层温度下降量越大、下降速率越快,呈正相关关系;②巷道温度的变化同时受到抛出煤体解吸瓦斯、喷出瓦斯膨胀泄压、冲击波扰动以及与环境热交换等多种因素影响,表现为先短暂上升,随后立即大幅下降,最后升温至环境温度的演化趋势,3次试验中,巷道温度下降量峰值分别为3.19、2.41、1.09 ℃,平均下降速率分别为0.249、0.188、0.094 ℃/s;③煤层和巷道温度在时间演化上具有整体相似性,在变化幅度上具有显著差异性,突出煤体在巷道内的进一步破碎并大量解吸瓦斯,是巷道温度演化的主控因素,也是导致巷道温度下降量较大的主要原因。

       

      Abstract: A multifunctional outburst simulation test system was independently developed to monitor the temperature of the coal seam and roadway throughout the entire outburst process. Outburst simulation experiments under different gas pressures were carried out. The results show that: ① the coal seam gas pressure quickly drops to atmospheric pressure after outburst, however, the temperature evolution of coal seam has a certain lag, which is mainly controlled by the desorption of adsorbed gas and the expansion of free gas; three stages can be seen in the coal seam temperature evolution characteristics: quick decline, rapid increase, and slow change; peak values of coal seam temperature decline are 0.56, 0.23, and 0.11 ℃, respectively, and average decline rates are 0.042, 0.015, and 0.008 ℃/s when the adsorption gas pressure is 2.0, 0.85, and 0.35 MPa; the higher the gas pressure is, the greater the coal seam temperature decline and the faster the decline rate is, which is positively correlated; ② the change of the roadway temperature is simultaneously influenced by various factors such as desorption of gas from the outburst coal, expansion and pressure relief of ejected gas, shock wave disturbance and heat exchange with the environment, showing an evolutionary trend of a brief increase followed by an immediate and significant decrease and finally rise to the ambient temperature; in the three tests, the peak values of roadway temperature drop are 3.19, 2.41 and 1.09 °C, and the average decline rates are 0.249, 0.188 and 0.094 °C/s, respectively; ③ the coal seam and roadway temperatures have overall similarity in time evolution and significant difference in the magnitude of change; the further fragmentation of the outburst coal body in the roadway and the large amount of desorption of gas are the main controlling factors for the evolution of the roadway temperature and the main reason for the large amount of decrease in the roadway temperature.

       

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