包头市区粉土受盐酸污染的室内试验研究

发布时间：2018-04-27 06:39

本文选题：污染土 + 模拟试验　；参考：《内蒙古科技大学》2015年硕士论文

【摘要】：近些年，，随着经济的持续发展，在土木工程领域的生产实践过程中，发现因土体受污染而导致工程建设方面的问题越发增多。然而，我国目前对于受污染土体的性质变化规律及成因的研究仍有不足，尤其是酸污染粉土土性变化的机理方面的研究存有空白。针对这种情况，本文选取包头市区粉土，通过0%（清水）、1%、4%、8%、12%浓度盐酸的浸泡试验，模拟粉土受酸溶液污染，并通过土工试验、矿物成分分析、电镜扫描，对受污粉土物理、力学性质、组成成分、微观结构几方面进行研究，在一定程度上解释了粉土受酸溶液污染后，土性的变化特征和成因，研究的主要结论如下：（1）土体内次生矿物中的粘土矿物、水溶性盐中的难溶盐和有机质会与盐酸作用发生化学溶蚀、沉淀、羧酸根与氢离子结合等反应，生成新的矿物成分：粘土矿物氧化镁、难溶盐碳酸钙及有机质含量，都伴随盐酸溶液浓度的增大而减少。（2）分析盐酸污染后粉土试样的电子显微镜照片可以发现，土的微观结构亦随着盐酸浓度增加呈现如下变化：土颗粒表面平滑化、大颗粒的粒径变小、小颗粒数量减少、孔隙变大且加深、土颗粒间的接触方式改变、有新物质产生。（3）粉土的物理性质也发生改变。随着盐酸浓度的增加，土体的外观颜色加深，变得有腐蚀性气味。质量、干密度、比重减小，含水率、孔隙比增大。同时土的液限减小，塑限增大，塑性指数减小。（4）粉土的基本力学性质也发生变化。压缩系数变大、压缩模量减小，土体的压缩指数、体积压缩系数和回弹指数变大。同时土体的粘聚力增加，内摩擦角减小。
[Abstract]:In recent years, with the sustainable development of economy, in the process of production practice in the field of civil engineering, it is found that the problems in engineering construction are more and more caused by soil pollution. However, there are still some deficiencies in the study of the properties and causes of the contaminated soil in China, especially in the study of the mechanism of the acid-contaminated silt. In view of this situation, the silt of Baotou urban area was selected in this paper, and the soaking test with 12% hydrochloric acid concentration was carried out to simulate the contamination of silt by acid solution, and through geotechnical test, mineral composition analysis, scanning electron microscope, the physics of contaminated silt was studied. The mechanical properties, composition and microstructure of silt are studied in this paper. To some extent, the characteristics and causes of soil properties change after the silt is polluted by acid solution are explained. The main conclusions of the study are as follows: Clay minerals in secondary minerals in soil, insoluble salts and organic matter in water-soluble salts react with hydrochloric acid by chemical dissolution, precipitation, reaction of carboxylic acid with hydrogen ions, and formation of new mineral components: clay mineral magnesium oxide, The content of insoluble calcium carbonate and organic matter decreased with the increase of hydrochloric acid concentration. (2) the microstructures of silt samples after hydrochloric acid contamination were analyzed by electron microscopy. The microstructure of the soil changed as follows with the increase of HCl concentration: the surface of soil particles was smooth, the size of large particles became smaller, and the number of small particles decreased. The porosity becomes larger and deeper, the contact mode between soil particles changes, and new materials are produced. The physical properties of silt also changed. With the increase of hydrochloric acid concentration, the appearance color of soil deepened and became corrosive smell. Mass, dry density, specific gravity decrease, water content and porosity ratio increase. At the same time, the liquid limit of the soil decreases, the plastic limit increases and the plastic index decreases. The basic mechanical properties of silt also changed. The compression coefficient increases, the compression modulus decreases, and the compression index, volume compression coefficient and springback index increase. At the same time, the cohesion of soil increases and the angle of internal friction decreases.
【学位授予单位】：内蒙古科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU411

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