Abstract The swelling behavior of clayey materials has been studied for many years, and the influence of pore size distribution and suction has been found to be significant. Swelling tests with suction control have been commonly and successfully performed on highly expansive clayey materials, but such work has not always included materials with small percentages of expansive clay minerals. In this study, compacted bentonite (Be), clayey material (C) from claystone, and mixtures of bentonite with clayey material (BeC) and sandy material (BeS) were subjected to swelling tests by the constant volume method in both conventional oedometers with water hydration (water wetting) and oedometers with suction control by relative humidity imposed by NaCl solutions (vapor wetting). The C samples at the optimal moisture content showed no swelling pressure by the vapor wetting method, even for an initial suction of 40,000 kPa. The BeC mixtures showed a lower swelling pressure with the vapor wetting method than with the water wetting method for samples with less than 70% bentonite, whereas the BeS mixtures showed similar swelling pressures in both methods. The BeC and BeS samples had a maximum swelling pressure that was directly proportional to the percentage of bentonite added when tested by the water wetting method. Mixtures with the same percentage of bentonite showed an increase in the swelling pressure that was directly proportional to the initial suction imposed before the tests. Pore size distribution (PSD) curves generated before the swelling tests showed that the greater the initial interaggregate porosity difference among the BeC and BeS mixtures, the greater the swelling pressure difference among the BeC mixtures tested by the water wetting method and the BeS mixtures tested by the vapor wetting method for the same percentages of bentonite. The PSD analysis also showed that the mixtures with higher volumes of entrapped air had higher swelling pressures, mainly during testing by the water wetting procedure. Therefore, the results of the swelling tests are highly dependent on the initial sample suction and the clay mineralogy, but the swelling tests with the vapor wetting method may lead to measurements lower than actual swelling pressures when clayed materials with reduced percentages of expansive clays are tested.

中文翻译：

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压实膨润土/粘土和膨润土/砂混合物的孔径分布和膨胀行为

摘要 黏土材料的溶胀行为已被研究多年，发现孔径分布和吸力的影响是显着的。具有吸力控制的膨胀测试已普遍且成功地在高膨胀粘土材料上进行，但此类工作并不总是包括具有小百分比膨胀粘土矿物的材料。在这项研究中，压实的膨润土 (Be)、粘土质粘土材料 (C) 以及膨润土与粘土材料 (BeC) 和砂质材料 (BeS) 的混合物在两种常规固结仪中通过恒体积法进行溶胀试验。水合作用（水润湿）和通过 NaCl 溶液（蒸汽润湿）施加的相对湿度控制吸力的固结仪。即使初始吸力为 40,000 kPa，处于最佳含水量的 C 样品也没有通过蒸汽润湿法显示出膨胀压力。对于膨润土含量低于 70% 的样品，BeC 混合物在蒸汽润湿法下的溶胀压力低于水润湿法，而 BeS 混合物在两种方法中的溶胀压力相似。当通过水润湿法测试时，BeC 和 BeS 样品的最大溶胀压力与添加的膨润土百分比成正比。具有相同百分比膨润土的混合物显示膨胀压力的增加，这与测试前施加的初始吸力成正比。溶胀试验前生成的孔径分布 (PSD) 曲线表明，BeC 和 BeS 混合物之间的初始聚集体孔隙率差异越大，通过水润湿法测试的 BeC 混合物和通过以下方法测试的 BeS 混合物之间的溶胀压力差异就越大。相同百分比的膨润土的蒸汽润湿法。PSD 分析还表明，夹带空气量较大的混合物具有较高的溶胀压力，主要是在通过水润湿程序进行测试期间。因此，溶胀测试的结果高度依赖于初始样品吸力和粘土矿物学，但是当测试膨胀粘土百分比降低的粘土材料时，使用蒸汽润湿法进行的溶胀测试可能导致测量值低于实际溶胀压力.