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循环载荷下煤样声发射特征及渗透率变化规律研究

Study on acoustic emission characteristics and permeability change law of coal samples under cyclic loading

  • 摘要: 为了研究循环载荷下煤样声发射和渗透率变化特征,采用自主研发的三轴应力渗流试验系统,对煤样进行了不同应力水平循环加、卸载的声发射参数及渗透率测试,结果表明:声发射参数变化呈现较为明显的降低-稳定-增长三阶段特征,其与循环次数的关系曲线呈“U”型,随上限应力水平的升高,曲线从“U”型向“V”型发展;煤层渗透率变化呈现较为明显的降低-稳定-增长三阶段特征,其与循环次数的关系曲线也呈“U”型,随上限应力水平的升高,曲线从“U”型向“V”型发展;在煤样循环加载过程中,声发射参数变化与渗透率变化趋势一致,两者具有密切的关系。

     

    Abstract: This paper presents the results of an experimental study of acoustic emission characteristics and permeability of coal samples under cyclic loading. The tests were conducted using self-developed triaxial stress seepage experiment system by tested under different stresses levels. The test results showed that both the acoustic emission and coal permeability followed a pattern of reducing - stabilizing - increasing under cyclic loading. The curves representing the relationship between the acoustic emission and cyclic times and the permeability and cyclic time also had the same pattern. Their pattern showed a “U” shape at first, then developed to a “V” shape as the increase of stress. It is concluded that varieties for the acoustic emission characteristics and permeability of the coal samples are consistent, and associated with each other under cyclic loading.

     

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