粉质粘土中粘土矿物对冻胀影响试验研究

发布时间：2018-05-29 13:24

本文选题：冻胀 + 粘土矿物　；参考：《中国矿业大学》2017年硕士论文

【摘要】：本文以粘土矿物对冻胀的影响为研究内容,自行设计加工了单向冻结、无压补水的冻胀试验系统。试验采用由蒙脱土、伊利土、高岭土、硅粉与玻璃微珠按照一定比例混合制备而成的人工配比试样,对一定温度、补水条件下试样的冻胀量、补水量以及试样温度变化规律进行了系统研究。与单质粘土冻胀敏感性蒙脱土伊利土高岭土不同,冻胀试验结果表明,相同含量情况下,冻胀量玻璃微珠-蒙脱土类玻璃微珠-伊利土类玻璃微珠-高岭土类,而玻璃微珠-硅粉类均不冻胀。这种差异性不能被忽视,因此在实际工程中,不应只按照工程分类标准判断土体的冻胀敏感性,还需要更多地考虑土中粘土矿物的成分与含量。同时,颗粒级配是影响冻胀的重要因素,因为不同颗粒级配反映了土体矿物成分的差异,而不同粘土矿物间粒径的微小差异则不是影响冻胀的主要因素。综合分析冻胀试验结果,由于玻璃微珠表面疏水,毛细水不发育,因此试样在冻结过程中水分迁移主要来自薄膜水。玻璃微珠-硅粉类试样缺乏持水性,在冻结过程中,部分孔隙水受压向下排出,因此不发生冻胀,而玻璃微珠-粘土矿物类试样中粘土矿物具有较强的亲水性,表面形成结合水,自由水渗流受到结合水粘滞作用产生的阻力,在负温下原位冻结。其中蒙脱土含量20%的试样部分冻胀量来源于薄膜水迁移,其余试样的冻胀量主要来源于土中水的原位冻结。粘土矿物增强了土体的持水能力,但其含量超过30%时,阻碍了水分迁移的通道,同时也增加了未冻水的含量。
[Abstract]:In this paper, the effect of clay minerals on frost heaving is studied, and a unidirectional freezing test system with no pressure rehydration is designed and processed by ourselves. In the experiment, a mixture of montmorillonite, Illite, kaolinite, silica powder and glass microbeads was prepared in a certain proportion. The frost heaving capacity of the sample was measured under certain temperature and rehydration conditions. The changes of water supply and sample temperature were studied systematically. Different from montmorillonite Illite kaolin, the frost heaving test results show that the frost-heaving amount of glass bead, montmorillonite glass bead, Illite glass bead and kaolinite is different from that of montmorillonite. And glass beads-silica fume are not frozen-heaving. This difference can not be ignored. Therefore, the frost heave sensitivity of soil should not only be judged according to engineering classification criteria, but also the composition and content of clay minerals in soil should be considered more. At the same time, particle gradation is an important factor affecting frost heave, because different particle gradation reflects the difference of mineral composition of soil, while the minor difference of particle size between different clay minerals is not the main factor affecting frost heave. Comprehensive analysis of the frost heaving test results show that the water migration of the samples mainly comes from the film water during the freezing process because the surface of glass beads is hydrophobic and the capillary water is not developed. The glass bead silica fume sample is short of water holding capacity. During the freezing process, some pore water is discharged under pressure, so it does not frozen-heave, while the clay mineral in glass bead clay mineral sample has strong hydrophilicity. The free water percolation is subjected to the resistance caused by the binding water viscosity and freezes in situ at negative temperature. Some of the frost heaving of the samples with 20% montmorillonite content comes from the film water migration, and the other samples mainly come from the in situ freezing of the water in the soil. Clay minerals enhance the water holding capacity of soil, but when the content of clay mineral exceeds 30%, it hinders the passage of water migration and increases the content of unfrozen water.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU41

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