李喜安, 薛泉, 庞涛, 郭泽泽, 师建锋. 2019: 基于原位渗气试验的黄土潜蚀地层渗气率研究. 工程地质学报, 27(5): 1027-1034. DOI: 10.13544/j.cnki.jeg.2019069
    引用本文: 李喜安, 薛泉, 庞涛, 郭泽泽, 师建锋. 2019: 基于原位渗气试验的黄土潜蚀地层渗气率研究. 工程地质学报, 27(5): 1027-1034. DOI: 10.13544/j.cnki.jeg.2019069
    LI Xi'an, XUE Quan, PANG Tao, GUO Zeze, SHI Jianfeng. 2019: A NEW IN-SITU TEST METHOD OF GAS PERMEABILITY AND IT'S UTILITY ON THE FIELD OF SUFFOSION LOESS. JOURNAL OF ENGINEERING GEOLOGY, 27(5): 1027-1034. DOI: 10.13544/j.cnki.jeg.2019069
    Citation: LI Xi'an, XUE Quan, PANG Tao, GUO Zeze, SHI Jianfeng. 2019: A NEW IN-SITU TEST METHOD OF GAS PERMEABILITY AND IT'S UTILITY ON THE FIELD OF SUFFOSION LOESS. JOURNAL OF ENGINEERING GEOLOGY, 27(5): 1027-1034. DOI: 10.13544/j.cnki.jeg.2019069

    基于原位渗气试验的黄土潜蚀地层渗气率研究

    A NEW IN-SITU TEST METHOD OF GAS PERMEABILITY AND IT'S UTILITY ON THE FIELD OF SUFFOSION LOESS

    • 摘要: 利用改进的渗气仪器对不同地区原位马兰黄土地层及原状马兰黄土试样的渗气率进行了测量。通过新研制的原位渗气率试验装置和已有成熟经验的室内原状黄土试样渗气率试验装置的渗气率测定结果进行对比,对原位渗气率试验结果的可靠性进行了验证;结合两种渗气率试验方法所得的结果综合分析了颗粒粒径、孔隙比、含水率等因素对马兰黄土渗气率的影响规律及其机理;通过原位渗气率试验分析了湿陷裂缝(隙)和潜蚀洞穴对黄土地层渗气率的影响规律及其机理。结果表明:原状黄土试样室内渗气试验与黄土地层原位渗气试验获得的结果基本一致,黄土地层原位渗气率试验结果是可靠的。原位试验因能够最大程度上避免试样取样、运输及室内制样等过程的扰动影响而结果更为精确,且能较好地反映黄土地层的真实情况,室内渗气率试验只适合均匀、无明显节理裂缝(隙)的黄土试样。两种渗气率试验结果均表明:马兰黄土粗颗粒愈多级配愈差渗气率愈大,反之渗气率则愈小;同一地点随深度增加、孔隙比减小、含水率增大,渗气率呈现减小的趋势。潜蚀黄土场地湿陷裂缝(隙)和潜蚀洞穴附近黄土地层因受裂缝(隙)和洞穴扰动,渗气率明显偏大,而远离湿陷裂缝(隙)和潜蚀洞穴的黄土地层渗气率基本接近于非洞穴裂缝(隙)分布区黄土渗气率平均值。原位渗气率测量结果精确,测量过程快速便捷,该方法在评价黄土地层渗透性乃至评价黄土地层结构缺陷(如隐伏节理裂隙、潜蚀洞穴的发育程度)等方面具有广阔的应用前景。

       

      Abstract: The gas permeability values of in-situ and undisturbed Malan loess samples at different areas are measured with improved air permeameter. The reliability of the in-situ gas permeability test is verified by comparing the results of in-suit and indoor gas permeability. The effects of particle size, pore ratio and water content on the gas permeability are compared and analyzed with a method of combining the two kinds of gas permeability. The effects of collapsible cracks(fractures) and suffosion caves on the gas permeability of loess are analyzed with in-situ test. The results show that the indoor and the in-situ gas permeability are basically consistent, the in-situ gas permeability test results are reliable. The in-situ gas permeability test removes the impact of transport disturbances and can be more accurate and reflect the real situation of loess. The indoor gas permeability test is only suitable for the uniform loess sample without obvious cracks. As the coarse particles of the Malan loess increase the gas permeability increases, otherwise the gas permeability decreases. As the loess depth increases, the void ratio decreases, the water content increases, and the gas permeability decreases. As the loess near the collapsible cracks(fractures) and suffosion caves, the gas permeability increases obviously. As the loess far from the collapsible cracks(fractures) and suffusion caves the gas permeability is tend to an average value. The in-situ gas permeability measurement process is fast and convenient. This method has broad application prospects in evaluating the permeability and structural defects in the loess.

       

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