不同加载条件下原煤力学渗流特性试验研究

    Experimental Study on Mechanical and Seepage Characteristics of Raw Coal Under Different Loading Conditions

    • 摘要: 以潞安集团常村煤矿煤样为研究对象,利用WYS-800微机控制电液伺服三轴试验装置研究不同加载条件下原煤的力学渗流特性。结果表明,三轴压缩煤样的极限抗压强度和弹性模量均大于单轴条件下的相应值;随着围压的不断增大,煤样抗压强度和弹性模量也会增大,且弹性模量呈现很好的线性;循环加卸载轴压应力-应变曲线在一定程度上受制于常规三轴压缩试验相应曲线,峰值强度降低;煤岩应力-体应变曲线,在低围压试验下表现出扩容机制;在高围压条件下,从峰前至峰后,煤样体积始终呈压缩状态。三轴压缩条件下含瓦斯煤的渗透率与轴向应变呈斜“V”字型走势;循环加卸载轴压试验,随着加卸载次数的增加,煤样渗透率整体降低,但降低梯度减小。

       

      Abstract: Taking the coal sample from Lu’an Group Changcun Coal Mine as the research object, we researched the mechanical and permeability characteristics of coal containing gas by using WYS-800 microcomputer control electro-hydraulic servo triaxial test device under different loading conditions. The results show that the ultimate compressive strength and elastic modulus of compression of coal in three axial compression are larger than the corresponding value of uniaxial conditions; with the increasing of confining pressure, the compressive strength and elastic modulus of coal will also increase, and the elastic modulus shows good linearity; stress-strain curve under cyclic loading and unloading tests is subject to the corresponding curves of conventional triaxial compression tests in a certain extent, and the peak strength decreases; the stress body strain curve of coal rock showed expansion mechanism under low confining pressure; however, under higher confining pressure, the coal sample body is always in a compressed state in pre-peak and post-peak. The relation between the permeability of coal containing gas and the strain presents a trend of inclined letter “V” under triaxial compression. With the increase of loading and unloading times in cyclic loading and unloading axial compression test, the permeability of coal sample decreases, but the decreasing gradient decreases.

       

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