不同矿化度水淋洗对盐碱土电阻率及水盐运移的影响试验

Experimental study on saline surface resistivity and salt transport affected by mineralization degree of leaching water

为了了解各种矿化度水质淋洗盐渍土后土体电阻率的变化和水盐运移规律,利用滨海盐渍土完成室内试验,通过自主研发改进型高密度电阻率探杆监测系统调控不同矿化度淋洗水质、时间、含水率变化三个因素,分别研究了不同矿化度水质淋洗后表层（0-10 cm）土壤电阻率随含水率和时间的变化,以及矿化度对土壤水分运移速率的影响,并获得土体水盐运移的一般规律。试验结果表明：不同矿化度水质淋洗后,随含水率的增加,电阻率均降低,矿化度越高,电阻率总体值越低。不同矿化度水质淋洗后,对土壤表层电阻率随含水率的变化进行拟合,得到均符合指数函数的衰减规律。淋洗后,土壤表层电阻率随时间推移表现出增大的现象。淋洗水质矿化度越高,水盐运移速率越大。不同矿化度水质淋洗后,土体垂向上表现出盐分重新分布的变化规律,表现为土壤电阻率随着深度增大而逐渐减小的趋势。

To better understand the changes of resistivity of saline soil and salt migration characteristics leached by the water with different mineralization degree,in this study we took inshore saline soil for laboratory test,and used the self- made modified resistivity monitoring system to control the three trial factors： mineralization degree of leaching water,water content of soil,and leaching time,to study the change of resistivity of surface layer（ 0 - 10cm）,and the general rules of water and salt migration in the soil. The experimental results proved that： with the increase of water content,the resistivity decreased; the higher the salinity,the lower the overall value of resistivity. In the surface layer of soil,the resistivity declined in an exponential function to water content,and increased with time prolonged. The higher the mineralization degree of leaching water,the higher migration rate for water and salt in the surface soil. The soil would have a new salinity distribution along the vertical section after leached,which were reflected as the resistivity decrease with the increasing depth.