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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。
Aiming at low, medium and high dry densities of low liquid limit and high liquid limit compacted clay, comparative study on permeability and pore structure undergoing wetting and drying cycles was carried out. The results show that under the same liquid-liquid conditions, the increase of permeability coefficient of high-pressure solid clay is higher than that of low-pressure-solid clay under the same liquid-tight conditions. Under the same dry density, the increase of permeability coefficient of high- Limited clay. During the wet-dry cycle, the effect of pore structure damage on permeability coefficient increases with the increase of compaction degree and liquid limit. The influence of fracture development on permeability coefficient increases with the increase of compaction degree and liquid limit Lower. During the wet-dry cycle, the low-liquid-content compacted clay samples only shrink without cracking, while the cracks in high-liquid-limited clay develop evidently. Small size infiltration samples can not fully reflect the influence of fracture development on the permeability coefficients, and the permeability coefficients change more Is caused by the change of pore structure. It is suggested that the permeability of different liquid-limit clays under wet-dry cycling should be further investigated by field penetration test or large-size indoor penetration test.