干湿循环作用下高低液限黏土防渗性能对比研究  

A comparative study of anti-seepage performance of clays with high and low liquid limits under drying-wetting cycles

作　　者：赵立业[1,2] 薛强[1,2] 万勇[1] 刘磊[1] 

机构地区：[1]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,湖北武汉430071 [2]中国科学院武汉岩土力学研究所湖北省固体废弃物安全处置与生态高值化利用工程技术研究中心,湖北武汉430071

出　　处：《岩土力学》2016年第2期446-452,464,共8页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.51279199);国家重点基础研究发展计划项目(973项目)(No.2012CB719802);国家重大水专项课题(No.2011ZX07104-002-02)~~

摘　　要：针对低、中、高3种干密度的低液限和高液限压实黏土,开展经历干湿循环过程的渗透系数和孔隙结构变化特征对比研究。结果表明:经3次干湿循环后,相同液限条件下,高压实黏土渗透系数增加比例高于低压实黏土;相同干密度条件下,高液限黏土渗透系数增加比例高于低液限黏土。干湿循环过程中,压实黏土孔隙结构损伤对渗透系数影响随着压实度和液限的提高而加大,而裂隙的发育对渗透系数影响随着压实度的增加和液限的降低而降低。干湿循环过程中低液限压实黏土试样只收缩不开裂,而高液限黏土裂隙发育明显,小尺寸渗透试样无法完全反映裂隙发育对渗透系数的影响,其渗透系数的变化更多是孔隙结构的变化所致,建议通过现场渗透试验或室内大尺寸渗透试验对干湿循环作用下不同液限黏土渗透系数的差异作进一步研究。The changes of permeability coefficient and pore structure of clays with high liquid limit and low liquid limit after drying-wetting cycles are compared. For each clay three densities are examined. The results show that after three drying-wetting cycles a larger increase in permeability coefficient is observed in clay with high degree of compaction than that with low degree of compaction when the liquid limits are the same. At the same dry density, the clay with high liquid limit exhibits larger increase in permeability coefficient than low liquid limit clay after drying-wetting circles. During the drying-wetting process, the influence of pore structural damage on permeability coefficient increases as compactness and liquid limit increase. The influence of cracks on permeability coefficient, however, decreases when the compactness increases and the liquid limit decreases. In contrast to low liquid limit clay which does not crack but shrinks after drying-wetting cycles, high liquid limit clay forms significant cracks. The change in permeability coefficient of the samples of the small size is mainly caused by the pore structure, and cannot reflect the influence of cracks. It is suggested that further research on the difference between permeability coefficients of clays with different liquid limits under drying-wetting cycles be carried out through permeability test on site or indoor large-size permeability test.

关 键 词：填埋场 压实黏土 液限 渗透系数 孔隙结构 

分 类 号：TU442[建筑科学—岩土工程]