不同降雨强度下滨海盐渍土水盐运动规律模拟实验研究

采用原状土柱 ,对滨海盐渍土的水盐运动进行了室内模拟研究。结果表明 :7,14和 2 8mm的雨量下 ,滨海盐渍土土壤剖面的水分运动规律基本相似 ,水分运动的整个过程可分为两个阶段 ,即入渗控制阶段和蒸发控制阶段。第 1阶段经历的时间很短 ,第 2阶段经历的时间较长 ,其水吸力随时间变化趋势符合对数方程 ,达到极显著水平。剖面上盐分运动规律却具有明显的差异性 :小雨时土体中的盐分再分布十分缓慢 ,甚至基本没有变化 ;中雨和大雨时土体中的盐分明显发生再分布 ,且也可以分成两个阶段 ,即盐分迅速下降阶段和盐分缓慢上升阶段。中雨和大雨第 2阶段盐分随时间的变化趋势也符合对数方程 ,达到极显著水平。就脱盐效果而言 ,小雨很难使土体脱盐 ;中雨能使土体在短时间内部分脱盐 ,但长期而言 ,整个剖面脱盐效果不理想 ;大雨能使整个土壤剖面长期处于脱盐状况 ,因此脱盐效果好

Simulation on water and salt movement in seashore saline soil under different rainfall intensities

Simulation was conducted to study the relative movement of salt and water in seashore saline soil in three undisturbed soil columns.Under different rainfall intensities,water movement in seashore saline soil was basically similar, and the whole process of water movement was divided into two phases,namely rapidly decreasing phase of water suction and slowly rising phase of water suction.The first phase in time was experienced more quickly,while the second more slowly.Meantime,the relationship between water suction and time could be expressed by a logarithmic equation,and its value amounted to significant lever in this experiment.And significant differences also happened in those of salt movement.With different rainfall intensities,light rain had a great difficulty to make the salt move in three soil columns,but moderate and heavy rain could induce the salt to move from the upper layers to sub layers.The whole process of salt movement could also be divided into two phases:the first was a rapidly decreasing phase of salt,the second was a slowly increasing phase of salt and the second phase could also be expressed by a logarithmic equation.In conclusion,light rain(7 mm)had no effect on desalination while moderate rain(14 mm)and heavy rain(28 mm)had a certain and great effect on desalination,respectively.