不同应力路径下含瓦斯煤岩渗流特性与声发射特征实验研究

 对含瓦斯煤岩进行常规三轴路径和卸围压路径的渗流特性与声发射特征实验，研究2种路径下煤岩失稳破坏过程中渗流特性和声发射特征的差异。结果表明：常规三轴路径和卸围压路径下含瓦斯煤岩的应力、瓦斯流量与声发射信号均具有较好的相关性，2种路径下含瓦斯煤岩的流量曲线具有相似的变化规律，常规三轴路径下瓦斯流动困难点存在滞后性，卸围压路径下瓦斯流动困难点与卸围压起始点相对应。与常规三轴路径相比，卸围压路径下含瓦斯煤岩失稳破坏过程中产生的累积损伤要大，从卸围压起始点开始声发射累积振铃数曲线斜率明显增大，且在失稳破坏点出现了急剧增大的拐点。2种路径下含瓦斯煤岩的声发射幅值曲线变化规律不同，与常规三轴路径相比，卸围压路径下含瓦斯煤岩的声发射幅值曲线呈现出以卸围压起始点为界的双峰状态。

EXPERIMENTAL STUDY OF CHARACTERISTICS OF SEEPAGE AND ACOUSTIC EMISSION OF GAS-FILLED COAL UNDER DIFFERENT STRESS PATHS

A series of tests on characteristics of acoustic emission(AE) and seepage have been performed on gas-filled coal under conditions of conventional triaxial path and unloading confining pressure path. The difference in characteristics of AE and seepage of coal during failure process under two paths is studied. The results show that characteristics of AE and seepage change with stress paths. In the two paths tests，stress，gas flow and AE signal of gas-filled coal have good correlations；and the curve of gas flow has the similar change rules. The suffering point of gas flow lags in conventional triaxial path，but also an obvious and direct correspondence exists between the suffering point of gas flow and starting point under the unloading confining pressure path. Compared with the conventional triaxial path，the cumulative damage is bigger under the unloading confining pressure path. The curve slope of AE cumulative ringing from unloading confining pressure starting point increases obviously，and experiences a sharp increase in failure point. In the two paths tests，AE amplitude curves have different variations；and AE amplitude curves of gas-filled coal show a bimodal state bounded by the starting point under unloading confining pressure path.