The effect of the coal seam water infusion to reduce dust is directly related to the development degree of the coal structure under the action of the effective stress. Therefore, this paper first summarizes several basic effective-stress models and proposes the effective-stress model considering the capillary force. Thereafter, the nuclear magnetic resonance (NMR) experiment system high-voltage seepage module is used to achieve the saturation coal sample T[Formula: see text] and water infusion coal sample T2 test under different mechanical environments. And the fractal dimension was calculated based on the results of porosity and pore size test. Finally, the parameters were sequentially substituted into effective-stress models. The calculation results were compared and analyzed. The results show that the saturation levels of the irreducible fluid of Sample DLT and Sample XLZ are 92.93% and 93.66%, respectively, indicating that these samples are dense porous media structures. Meanwhile, the porosity test shows the overall porosity with the water infusion pressure and confining pressure changes being consistent with the conventional law; the partial porosity caused a slight fluctuation due to different sensitivities of different pores to stress. The effective stresses of the capillary force and the calculated effective stress of the body are closest to the fractal effective stress, so the difference between the two values is negligible due to the small capillary force, which indicates that during the high-pressure water infusion, the capillary force in the meso-structure hardly affects the mechanical environment. Based on the theoretical research results, this paper can provide a theoretical reference for the determination of water infusion parameters under different on-site mechanical environment during the process of coal seam water infusion, which is conducive to the popularization and application of this technology, thus, providing the scientific basis for safe mining of the deep coal seam and ensuring the safe and efficient production of mines.

中文翻译：

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基于分形理论的煤层注水过程有效应力动态演化规律研究

煤层注水降尘效果与煤层结构在有效应力作用下的发育程度直接相关。因此，本文首先总结了几种基本的有效应力模型，提出了考虑毛细力的有效应力模型。此后，利用核磁共振（NMR）实验系统高压渗流模块实现饱和煤样T[公式：见正文]和注水煤样T2在不同的机械环境下进行测试。并根据孔隙率和孔径测试结果计算分形维数。最后，将参数依次代入有效应力模型。计算结果进行了对比分析。结果表明，样品DLT和样品XLZ的束缚流体饱和度分别为92.93%和93.66%，表明这些样品为致密多孔介质结构。同时，孔隙度试验表明，整体孔隙度随注水压力和围压变化符合常规规律；由于不同孔隙对应力的敏感性不同，部分孔隙度引起了轻微的波动。毛细管力的有效应力和计算的本体有效应力最接近分形有效应力，因此由于毛细管力较小，两者之间的差异可以忽略不计，这表明在高压注水过程中，细观结构中的毛细力几乎不影响力学环境。基于理论研究成果,本文可为煤层注水过程中不同现场力学环境下注水参数的确定提供理论参考,有利于该技术的推广应用,从而，为深部煤层安全开采提供科学依据，保障矿山安全高效生产。由于毛细力较小，两者的差异可以忽略不计，说明在高压注水过程中，细观结构中的毛细力几乎不影响力学环境。基于理论研究成果,本文可为煤层注水过程中不同现场力学环境下注水参数的确定提供理论参考,有利于该技术的推广应用,从而，为深部煤层安全开采提供科学依据，保障矿山安全高效生产。由于毛细力较小，两者的差异可以忽略不计，说明在高压注水过程中，细观结构中的毛细力几乎不影响力学环境。基于理论研究成果,本文可为煤层注水过程中不同现场力学环境下注水参数的确定提供理论参考,有利于该技术的推广应用,从而，为深部煤层安全开采提供科学依据，保障矿山安全高效生产。细观结构中的毛细力几乎不影响力学环境。基于理论研究成果,本文可为煤层注水过程中不同现场力学环境下注水参数的确定提供理论参考,有利于该技术的推广应用,从而，为深部煤层安全开采提供科学依据，保障矿山安全高效生产。细观结构中的毛细力几乎不影响力学环境。基于理论研究成果,本文可为煤层注水过程中不同现场力学环境下注水参数的确定提供理论参考,有利于该技术的推广应用,从而，为深部煤层安全开采提供科学依据，保障矿山安全高效生产。