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为探究粗颗粒硫酸盐渍土含水率单次递减条件下的盐胀特性,利用自主设计的多功能盐胀试验装置,开展了粗颗粒硫酸盐渍土盐胀率随4因素(孔隙比、含盐量、温度、初始含水率)变化规律的试验研究。试验结果表明,硫酸盐渍土的体积变化受两种效应的影响:含水率递减引起的干缩效应以及土体中硫酸钠相态变化引起的盐胀效应。含水率单次递减过程中硫酸盐渍土的失水速率与硫酸盐渍土的孔隙比、试样温度、初始含水率呈正相关关系;而与硫酸盐渍土的含盐量呈负相关关系。试验结果中部分试样的盐胀率达到了9%,这表明粗颗粒硫酸盐渍土在含水率单次递减条件下引发的盐胀不容忽略。其研究结果可为西北地区高含盐量的残余型硫酸盐渍土的盐胀性评价提供参考依据。
In order to explore the salt expansion characteristics of single-desiccated coarse-grained sulfate saline soils, the salt expansion of coarse-grained sulfate saline soils with four factors (porosity ratio, Salt content, temperature, initial water content). The experimental results show that the volume change of sulfate saline soil is affected by two effects: the shrinkage effect caused by decreasing water cut and the salt expansion effect caused by the change of phase state of sodium sulfate in soil. The rate of water loss of sulphate saline soil during the single descending process of moisture content is positively correlated with the porosity ratio, sample temperature and initial moisture content of sulphate saline soil, but negatively correlated with the salt content of sulphate saline soil. In the test results, the salt expansion rate of some samples reached 9%, which indicates that the salt swollen of coarse-grained sulfate soil should not be neglected under the single-descending water cut. The results of this study can provide a reference for the evaluation of salt expansion of high salinity residual sulphate soils in Northwest China.