大孔隙扭曲度对土壤水分入渗的影响

Effect of Macropore Tortuosity on Soil Infiltration

[目的]探究大孔隙扭曲度对土壤水分入渗的影响,为深入了解大孔隙扭曲度影响优先流的物理机制提供理论依据。[方法]采用室内含大孔隙土柱的定水头入渗试验,以长武地区黑垆土为研究对象,分析大孔隙不同扭曲度对土壤湿润锋运移、累积入渗量和水分穿透时间的影响。[结果]大孔隙的形状深刻影响入渗湿润锋的形状,对湿润锋纵向、横向运移具有引导作用;大孔隙扭曲度减小可加速湿润锋运移,增加累计入渗量;水分穿透土柱的时间随扭曲度的增大而增加,穿透时间与扭曲度可用对数关系描述;湿润锋运移深度、累积入渗量与时间均呈明显的乘幂关系,其函数式的参数取决于土体中大孔隙扭曲度。[结论]大孔隙扭曲度对水分入渗影响深刻,是研究大孔隙流的重要因素。

[Objective] The effect of macropore tortuosity on infiltrition was examined in order to provide theoretical basis for how tortuosity influenced preferential flow transport. [Methods] The laboratory soil column infiltration experiments were conducted with man-made macropore in Heilu soils under different initial tortuosity. The effects of macropore tortuosity on wetting front migration, cumulative infiltration and penetration time were determined. [Results] The macropore tortuosity considerably influenced the shape of the wetting front migration and its movement in vertical and lateral directions; the decrease of macropore tortuosity could accelerate the migration of wetting front and increase the cumulative infiltration; the time for water to penetrate the soil column increased with the rise of macropore tortuosity; the depth of wetting front migration and the amount of cumulative infiltration had the exponential relationship with time. The parameters in these functions depended on the macropore tortuosity. The relationship between penetration time and macropore tortuosity could be described by a logarithmic function. [Conclusion] The macropore tortuosity extensively impacted some factors of infiltrition, and was one of the most important factors in studying preferential flow.