全吸力范围的盐渍土持水特性的试验研究

Experimental study on water retention characteristics of saline soil in the full suction range

盐渍土中含有大量易溶盐,含水率和吸力变化对其工程性质产生重要影响。现有针对盐渍土持水特性的研究较少,尚未得到全吸力范围内统一、明确的土-水特征曲线试验觃律。采用压力板法、蒸汽平衡法和冷镜露点法3种方法测量盐渍土的基质吸力和总吸力,并通过试验手段探究压实度和含盐量对盐渍土持水特性的影响觃律。试验结果表明:在低吸力阶段,随着压实度的增加,土样的饱和体积含水率降低,进气值提高;持水能力随着压实度和孔隙溶液浓度的增加而提高,并且低压实度时孔隙溶液浓度对基质吸力影响明显。在高吸力阶段,含盐量较高时压实度对土样土-水特征曲线的影响明显,并且土体的持水能力随含盐量增加而增强。

Saline soil contains a large amount of soluble salts,and the change of water content and suction has an important effect on its engineering properties.At present,few studies focus on the water retention characteristics of saline soil,and there is no uniform and clear soil water characteristic curve of saline soil in the full suction range.In this paper,the pressure plate method,vapor equilibrium method,and chilled-mirror dew-point technique were used to measure the matric suction and total suction of saline soils.The influences of compaction degree and salt contents on the water retention characteristics of saline soils were studied by experiments.The experimental results showed that in the low suction range,with the increasing of compaction degree,the saturated volumetric water content of the soil sample decreases and the value of air-entry suction increases.The water retention capacity increases with the increase of compaction degree and pore solution concentration,and the pore solution concentration has an obvious influence on the matric suction especially for the soil with low compaction degree.In the high suction range,for the soil with high salt content,the compaction degree has a significant influence on the soil-water characteristic curve,and the water retention capacity of soil increases with the increasing of salt content.