土体持水特性及孔隙水分布特性的试验研究

发布时间：2018-05-11 22:28

本文选题：土-水特征曲线 + 非饱和土　；参考：《工程地质学报》2017年01期

【摘要】：采用轴平移技术对砂土、粉质黏土、黏土3种土质的土-水特征曲线进行了测试分析,并结合核磁共振技术测得了试样在不同基质吸力加载步条件下的T_2时间(横向弛豫时间)分布曲线,从细微观角度分析了脱湿过程中孔隙水在土体中赋存分布的情况。实验结果表明:3种土质的体积含水率随着控制吸力的增大而减少,该脱湿曲线可分为边界效应区、过渡区与残余区3个区域。其中,黏土的持水特性明显大于粉质黏土和砂土。核磁共振的试验结果与压力板仪获得的脱湿过程是对应的,从微细观角度展示了土体的排水过程。在排水过程中,总体上具有较大势能的大孔隙水先排出,随后小孔隙开始排水,但这一规律并不绝对,由于土体孔隙结构的复杂性,会出现大小孔隙同时排水以及土样中水分重分布的现象。
[Abstract]:The soil-water characteristic curves of sand, silty clay and clay were measured and analyzed by axial translation technique. The distribution curves of T _ 2 time (transverse relaxation time) of samples under different matrix suction loading steps were measured by nuclear magnetic resonance (NMR) technique. The distribution of pore water in soil during dehumidification was analyzed from a fine and microscopic point of view. The experimental results show that the volume moisture content of the three kinds of soils decreases with the increase of the controlled suction, and the desiccant curve can be divided into three regions: boundary effect zone, transition zone and residual zone. The water holding capacity of clay is obviously larger than that of silty clay and sand. The experimental results of nuclear magnetic resonance are corresponding to the dehumidification process obtained by the pressure plate instrument. The drainage process of the soil is shown from the microcosmic point of view. In the process of drainage, the large pore water with large potential energy is discharged first, and then the small pore begins to drain, but this rule is not absolute, because of the complexity of the pore structure of soil. Large and small pore drainage and water redistribution in soil samples will occur at the same time.
【作者单位】：山东省城乡建设勘察设计研究院;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;桂林理工大学土木与建筑工程学院;
【基金】：国家自然科学基金(11372078,51309055) 含天然气水合物土的关键试验技术与工程力学特性研究(NSFC51239010#)资助
【分类号】：TU43

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