降低强膨胀土膨胀率提高抗剪强度的复合改良剂筛选

为减小膨胀土对土木工程设施和农业生态环境的严重危害,该文进行复合改良膨胀土方法的室内试验。利用离子交换、高分子成膜作用,使用不同配比的石灰（CaO）、氯化钾（KCl）、聚乙烯醇（polyvinyl alcohol,PVA）、聚丙烯纤维组合对膨胀性土壤进行复合改良。通过54组自由膨胀率试验筛选出自由膨胀率低于40%且性价比高的改良组合（改良剂以质量分数计,下同）：0.8%PVA＋5%KCl、0.8%PVA＋4%CaO。最后根据2种组合设计5组（天然膨胀土、添加0.6%聚丙烯纤维、0.8%PVA＋5%KCl、0.8%PVA＋5%KCl＋0.6%聚丙烯纤维、0.8%PVA＋4%CaO）三轴压缩剪切试...

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Bibliographic Details
Published in农业工程学报 Vol. 33; no. 2; pp. 109 - 115
Main Author 沈泰宇 邢书香 汪时机 程明书 黄伟
Format Journal Article
LanguageChinese
Published 西南大学工程技术学院,重庆,400716 2017
Subjects
复合改良方法
成膜效应
抗剪强度
聚丙烯
聚乙烯醇
膨胀土
自由膨胀率
shear strength
film-effect
polypropylenes
抗剪强度
composed improvement methods
膨胀土
复合改良方法
free swelling ratio
expansive soil
聚乙烯醇
聚丙烯
polyvinyl alcohols
自由膨胀率
成膜效应
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ISSN1002-6819
DOI10.11975/j.issn.1002-6819.2017.02.015

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Summary:为减小膨胀土对土木工程设施和农业生态环境的严重危害,该文进行复合改良膨胀土方法的室内试验。利用离子交换、高分子成膜作用,使用不同配比的石灰（CaO）、氯化钾（KCl）、聚乙烯醇（polyvinyl alcohol,PVA）、聚丙烯纤维组合对膨胀性土壤进行复合改良。通过54组自由膨胀率试验筛选出自由膨胀率低于40%且性价比高的改良组合（改良剂以质量分数计,下同）：0.8%PVA＋5%KCl、0.8%PVA＋4%CaO。最后根据2种组合设计5组（天然膨胀土、添加0.6%聚丙烯纤维、0.8%PVA＋5%KCl、0.8%PVA＋5%KCl＋0.6%聚丙烯纤维、0.8%PVA＋4%CaO）三轴压缩剪切试验,测定抗剪强度并比较改良效果。自由膨胀率试验、三轴压缩剪切试验结果表明复合改良方法效果显著。经过0.8%PVA＋5%KCl的混合溶液改性,并添加0.6%聚丙烯纤维改良后的土样自由膨胀率由130%降至27%,三轴抗剪强度提高15%;经过0.8%PVA＋4%CaO的混合溶液改性的土样自由膨胀率由130%降至33%,三轴抗剪强度提高110%。研究表明：PVA的成膜效应能强化KCl、CaO对膨胀土水化膨胀的抑制作用;KCl、PVA对聚丙烯纤维提高抗剪强度有抑制作用;聚丙烯纤维能有效减少膨胀土裂隙的萌生,提高抗剪强度。该文提出的强膨胀土复合改良方法的有效性得到了室内试验的验证,可以为今后工程建设中膨胀土的改良、水土流失防治等提供参考。
Bibliography:11-2047/S
shear strength; polyvinyl alcohols; polypropylenes; film-effect; composed improvement methods; expansive soil; free swelling ratio
More than 5 billion dollars economic loss is caused by expansive soil each year around the world. Soil chemical amelioration is better than the other methods, but better effect and higher safety cannot be achieved by a single ameliorant. In order to weaken serious damages to civil engineering facilities and agricultural ecological environment induced by expansive soils, composed ameliorants to improve the expansive soil were tested in laboratory tests in this paper. The low free swelling ratio（no more than 40%） and the high shear strength were required for the soil amendment. Expansive soil used for testing was collected from Handan in Hebei province in China. It was a strong expansive soil with 130% free swelling ratio（more than 90%） and contained large hydrophilic minerals. Based on the physical-chemical effect of ion exchange（to decrease thickness of hydration shell）, p
ISSN:1002-6819
DOI:10.11975/j.issn.1002-6819.2017.02.015