土壤膨胀性对降雨入渗产流影响试验

The Soil Swelling on Effects of Rainfall Infiltration Tests

入渗产流是水循环的重要环节,膨胀性土会改变土壤水分运动参数,从而对降雨入渗产流过程产生影响。以具有膨胀性的黄绵土和娄土为研究对象,在室内模拟降雨条件下,研究了土壤膨胀性对4种厚度(分别为10、20、30、40cm)的土壤容重、累积入渗量、径流强度等土壤水分运动参数的影响,并采用Philip公式、Kostiakov公式和Horton公式对土壤水分运动特征曲线拟合。结果显示:各种厚度的膨胀性土壤受到膨胀力和重力双重作用均导致表层0~10 cm土壤平均干容重相对减小,10 cm以下深度土壤干容重随深度增加而相对增加。随着土壤厚度增大,黄棉土和娄土的土壤累积入渗量变小。径流强度随历时增加而增加,然后稳定,且因不同土层土壤颗粒稳定性不同影响波动幅度。Philip公式拟合效果不理想,Kostiakov公式只适用于土壤饱和段的拟合,而Horton公式考虑到膨胀土体积变化影响土壤饱和过程中土壤水入渗速率,适用于初始入渗至稳定入渗的过程。

Rainfall infiltration runoff is an important part of hydrologic cycle.Swelling soil will change soil water movement parameters,which will influence the rainfall runoff process.In this paper,the soil swelling effects on soil water movement parameters,including soil bulk density,cumulative infiltration and runoff intensity,are studied by the indoor artificial rainfall system with the Loessial soil and Lou soil,which are typical expansive soil.4 kinds of thickness（ 10,20,30,40 cm,） of expansive soils are designed.And the Philip the formula,Kostiakov formula and Horton formula are used to fit the water retention curve.The results show that all the expansive soils of different thickness are affected by both expansion force and gravity.The average dry bulk density of 0 ～ 10 cm soil decreases,and the dry bulk density of 10 cm increases with depth.With the increase in soil thickness,the cumulative infiltration rate of the soil and the soil of the Lossial soil and Lou soil become smaller.The runoff intensity increase with the increase in diachronic time,and then is stable,and the fluctuation amplitude is influenced by the different soil particle stability in different soil layers.The Philip formula is not ideal.The Kostiakov formula is only suitable for fitting the soil saturation section.Horton formula also takes account of the volume change of expansive soil,which affects the infiltration rate of soil water in the process of soil saturation,and is suitable for initial infiltration to stable infiltration process.