小雨条件下入渗土壤中水—气运移规律试验

探明非饱和土壤水分入渗中水—气运移的规律及相互关系,有利于促进水分入渗规律和溶质运移规律的深化研究。基于室内土柱试验,研究了在小雨量(15mm/d)连续降雨入渗条件和土中气相影响条件下水分入渗的变化规律。结果表明,土中水分入渗能力随时间和深度递减;气压势与含水率呈负相关,与基质吸力呈正相关;多项式和对数函数对土—水特征曲线的拟合较为理想;入渗系数随剖面深度加大而减少。试验结果较好地解释了试验过程中出现的积水现象,对深入研究非饱和土壤水分入渗规律意义重大。

Experimental Study on Soil Water-Air Infiltration Law under Slight Rain

Finding out the mutual relations between water and air in the unsaturated soils can contribute to the further research on the law of water infiltration and solute migration. Based on the indoor soil column experiment, this paper has researched the soil infiltration considering the influence of the air phase under the continuous slight rainfall (15 mm/d). As a result, water infiltration capacity in soils is decreasing over time. Air pressure potential is negatively correlated with water content and functions which give more relatively rational results are proposed as a reference to fit the soil-water characteristics. The infiltration coefficient is decreasing with the deeper profile depth. Meanwhile, the results analysis has better explained the phenomenon that there is water accumulated in the surface during the test period, which has a great deal of significance on the study of the water infiltration rule in the unsaturated soils.