西北寒旱区盐渍土水盐迁移规律研究

Study on Water and Salt Transfer Law of Asphalt Road in Cold and Drought Saline Area in Northwest China

我国盐渍土分布广泛,盐渍土地区道路结构深受硫酸盐盐胀性影响,尤其是路基的盐胀现象会日益明显。为了探究西部盐渍土地区水分、硫酸盐迁移规律,通过对南疆典型路段设置湿度传感器并取样勘测水泥稳定基层,观测路基含水量及含盐量的变化;同时模拟南疆地区自然环境,以及在室内进行水分、硫酸盐迁移特性的研究,分析了两种情况下水盐迁移规律。试验结果表明:新疆地区由于蒸发量较大,降雨量较小,路基含水量最大的时期不在雨季,而是在自然环境下蒸发量较小的4月、5月、6月;一定含量的Na2SO4会使水稳基层产生某种膨胀作用;水分和硫酸盐的迁移具有相似的特性,都是从试样的底部向顶部迁移。对于相同含水率、不同硫酸盐含量的盐渍土而言,盐分梯度是影响水盐迁移的主要因素;而对于硫酸盐含量相同、含水率不同的盐渍土,含水率的差别是水盐迁移的主要动力。

The saline soil is widely distributed in China,and the road structure in saline soil areas is greatly affected by the salt swell of sulfate,especially the swelling of the roadbed is becoming more and more obvious.In order to explore the rules of water and sulfate migration in western saline soil area,through setting the humidity sensor on the typical section of southern Xinjiang,sampling the water-stable base sample and observing the change of water content and salinity of the subgrade,at the same time simulating the natural environment of southern Xinjiang,and studying the characteristics of water sulfuric acid migration indoors,the rule of water and salt migration in two scenarios are analyzed.The experimental results show that:in Xinjiang,due to more evaporation and less rainfall,the period of maximum water content of the subgrade is not in the rainy season,but in April,May and June with less evaporation in the natural environment;a certain content of Na2 SO4 cause some expansion of the waterstable base;the migration of water and sulfate has similar characteristics,all moving from the bottom to the top of the sample.For the saline soil with the same water content and different sulfate content,the salt gradient is the main factor affecting the migration of water and salt.For the same salt content of sulfate,when the water content is different,the difference of water content is the main driving force of water and salt migration.