紫色土中砾石夹层对土壤水分入渗的影响

为探究紫色土中砾石夹层对土壤水分入渗的影响因素，通过室内模拟土柱入渗试验，采用一维垂直水头法研究2种砾石粒径（10~20 mm、20~76 mm）和5种砾石含量（0%、10%、20%、30%和40%）分别与累积入渗量、入渗特性和湿润锋进程之间的关系。利用Horton方程和Philip公式验证入渗特性，以及幂函数拟合湿润锋进程。结果表明:① 在相同砾石粒径下，累积入渗量随着砾石含量的增加而减小；对于20~76 mm粒径砾石夹层，20%砾石含量及以上含量对水分入渗的阻碍程度相似。② 当砾石粒径相同时，初始入渗率、平均入渗率、稳定入渗率都随砾石含量的增加而减小；当砾石含量相同时，大粒径砾石夹层的初始入渗率大于小粒径砾石夹层。③ 砾石粒径大小与其对湿润锋的阻碍程度呈负相关。④ Horton方程对累积入渗量变化规律的验证效果要优于Philip公式；幂函数能较好地模拟含砾石夹层土壤中湿润锋的进程。

Rock interbed containment effect on infiltration processes in purple soil regions

In order to explore the influence of the rock interbed on downward soil moisture infiltration, indoor soil column infiltration experiments were conducted to examine the relationship between 2 different gravel particle sizes (10-20 mm and 20-76 mm) and 5 different gravel contents (0%, 10%, 20%, 30%, and 40%), as well as the cumulative infiltration, infiltration characteristics, and the process of the wetting front. The Horton equation and Philip formula were used to verify the variations in the infiltration characteristics, and the power function was used to simulate the wetting front during the infiltration process. The results showed that: ① The cumulative infiltration becomes smaller with the increase in the rock content of the gravel particles of the same size. For particle sizes between 20 mm and 76 mm, the obstructions to the cumulative infiltration were similar above 20% of the rock content. ② The initial infiltration rate, average infiltration rate, and steady infiltration rate showed an obvious decline, along with the increase of the rock content. The initial infiltration rate of the larger-sized gravel particles is greater than that of the smaller-sized gravel particles. ③ There is a negative correlation between the size of the gravel particle and its obstruction to the wetting front. ④ The Horton equation's validation results of the infiltration characteristics were superior to those derived from the Philip formula; the power function had a good fitting result for the elapsed distance of the wetting front over time in a soil-rock mixture.