酸雨作用下红黏土渗透性影响机制及压实度控制

发布时间：2018-03-01 06:22

  本文关键词： 土力学 酸雨作用 红黏土 渗透性 压实度 结构损伤　出处：《岩石力学与工程学报》2016年S1期 　论文类型：期刊论文

【摘要】：酸雨会溶解红黏土中的部分物质,是导致红黏土路基病害的重要因素。研究红黏土在酸雨环境下的渗透机制、提出红黏土路基压实度建议标准对于红黏土地区路基设计具有很强的工程实际意义。设计新型的淋溶仪器,用不同p H值溶液模拟酸雨对原状红黏土进行淋溶后,进行渗透性试验、物相分析试验及电镜微结构扫描试验,深入分析酸雨对桂林红黏土渗透性的影响因素及影响机制;进一步通过试验研究重塑红黏土渗透系数与压实度的变化关系。结果表明:红黏土渗透系数随干密度增大而减小;红黏土中的主要物质成分包括铁、硅、铝和钾4种金属元素的化合物均能被酸性物质溶解,随地下水迁移而流失,造成土体结构孔隙比增大、内部的孔隙连通性增强,酸雨的p H值越小,这些物质的溶解程度越大,对红黏土的渗透性影响越大;当在p H值≥3的酸雨地区用红黏土作为路基填料时,控制路基压实度≥95%可有效预防酸雨对红黏土的不利作用。
[Abstract]:Acid rain dissolves some substances in red clay, which is an important factor leading to roadbed disease of red clay. The permeation mechanism of red clay in acid rain environment is studied. The paper puts forward that the recommended standard of compaction degree of red clay subgrade is of great practical significance for the design of roadbed in red clay area. A new type of leaching instrument is designed, which simulates the leaching of undisturbed red clay by acid rain with different pH values. The permeability test, phase analysis test and electron microscope microstructural scanning test were carried out to analyze the influence factors and mechanism of acid rain on the permeability of red clay in Guilin. The relationship between the permeability coefficient and compaction degree of remolded red clay is studied by experiment. The results show that the permeability coefficient of red clay decreases with the increase of dry density, and the main components of red clay include iron, silicon, silicon, iron and silicon. The compounds of aluminum and potassium can be dissolved by acidic substances, and lose with the migration of groundwater, resulting in the increase of structure / void ratio of soil mass and the increase of internal porosity connectivity. The smaller pH value of acid rain, the greater the dissolution degree of these substances. When red clay is used as subgrade filler in acid rain area with pH 鈮，

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