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采用稳态渗透法对破碎砂岩、破碎泥岩和破碎煤矸石进行渗透试验,分析粒径、有效应力和孔隙度对破碎岩石渗透性参量(渗透率、非Darcy流β因子)的影响.试验岩样粒径为0~2.5 mm、2.5~5 mm、5~10mm、10~13 mm和0~13 mm,通过轴向位移分别为4 mm、8 mm、10 mm、12 mm和14 mm控制孔隙度.试验结果表明:渗透液压越大,有效应力越大,渗透越快,流量越大;破碎岩样的有效应力与渗流速度可用线性关系拟合,并给出了有效应力直接估计渗透率的公式;破碎岩样随孔隙度增加,其渗透率增加,非Darcy流β因子减少,孔隙度大于0.4左右时,渗透率增加幅度变大,而当孔隙度小于0.35左右时,非Darcy流β因子变化较大;相同粒径的不同岩样,随孔隙度的增加,不同岩性岩样的渗透率变化程度和变化趋势不同,且孔隙度对不同岩性岩样的渗透率影响程度不同.
Permeability tests of broken sandstone, broken mudstone and broken coal gangue were carried out by steady infiltration method, and the influence of particle size, effective stress and porosity on the permeability parameters (permeability, non-Darcy flow β factor) of broken rock was analyzed. The particle sizes are 0 to 2.5 mm, 2.5 to 5 mm, 5 to 10 mm, 10 to 13 mm and 0 to 13 mm, and the controlled porosity is 4 mm, 8 mm, 10 mm, 12 mm and 14 mm, respectively, through axial displacement The experimental results show that the bigger the hydraulic pressure is, the larger the effective stress is, the faster the infiltration is and the higher the flow rate is. The effective stress and seepage velocity of the fractured rock can be fitted by the linear relationship, and the formula of the effective stress to directly estimate the permeability ; The permeability of the fractured rock samples increases with porosity, and the non-Darcy flow β factor decreases. When the porosity is greater than 0.4, the increase of permeability increases. When the porosity is less than 0.35, the change of β-factor of non-Darcy flow With the increase of porosity, the permeability and variation tendency of different lithology samples are different, and the influence of porosity on the permeability of different lithology samples is different.