NaCl溶液对土体持水特性影响的试验研究

发布时间：2018-07-06 20:36

本文选题：盐溶液 + 土-水特征曲线　；参考：《岩土力学》2015年10期

【摘要】：分别采用不同浓度的NaCl溶液对低塑性黏土进行饱和,然后进行压力板和蒸汽平衡法试验,获得整个吸力范围内的土-水特征曲线(SWCC)。分析不同浓度的孔隙溶液对SWCC的影响规律,结果表明:盐分对基质吸力的影响较小,对总吸力影响较大,这主要是因为盐溶液引起的渗透吸力所致。在蒸汽平衡法试验中,随着含水率的降低,孔隙浓度增大,渗透吸力增大。然而,基质吸力随着含水率的减小迅速增大,使得渗透吸力所占的比例逐渐减小。在非饱和土中,总吸力包括基质吸力和渗透吸力;基质吸力包括毛细部分和吸附部分,当土体中含水率较低时,主要是吸附效应在起作用;渗透吸力与溶液浓度有关。根据试验结果深入分析了吸附水膜和土颗粒之间的相互作用,得出由于溶质的存在对分子间吸附力的影响规律。根据表面化学原理,建立了分子间作用力和吸附水膜厚度之间的关系,以描述处于吸附状态的土-水特征曲线。
[Abstract]:The low plastic clay was saturated with NaCl solution of different concentrations, and then the soil-water characteristic curve (SWCC) in the whole suction range was obtained by the test of pressure plate and steam equilibrium method. The effects of different concentrations of pore solution on SWCC were analyzed. The results showed that the salt had little effect on the matrix suction and a greater influence on the total suction, which was mainly caused by the permeation suction caused by the salt solution. In the steam equilibrium test, with the decrease of water content, the pore concentration increases and the permeability suction increases. However, the matrix suction increases rapidly with the decrease of moisture content, which makes the proportion of permeable suction decrease gradually. In unsaturated soil, the total suction includes matrix suction and permeation suction, and the matrix suction includes capillary part and adsorption part. When the moisture content in soil is low, the adsorption effect is the main factor, and the permeation suction is related to the concentration of solution. Based on the experimental results, the interaction between adsorbed water film and soil particles was analyzed in depth, and the influence of solute on the intermolecular adsorption force was obtained. According to the principle of surface chemistry, the relationship between the intermolecular force and the thickness of the adsorbed water film was established to describe the soil-water characteristic curve in the adsorption state.
【作者单位】：中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室;
【基金】：国家自然科学基金(No.11502276,No.11372078)
【分类号】：TU411

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