中文摘要：

土壤入渗率的测量受到广泛关注与研究。环式入渗仪是目前广泛应用的土壤人渗性能测量仪器之一。模拟降雨法和双环法是目前测量土壤入渗的常用方法，圆盘入渗仪多用于测量土壤的饱和导水率。大量测量结果表明，环式人渗仪测量得到的最可靠结果是土壤稳定人渗率，但结果远高于人工降雨测量结果，说明环式人渗测量方法并不准确。环式入渗仪入土过程中，环与土壤间的缝隙为土壤水入渗，提供优先路径是造成测量结果远高于土壤本身人渗性能的重要原因。环式入渗仪测量过程中采用的时间步长偏大是产生入渗率偏大的另一原因。采用数值计算方法分析了计算人渗赋值方式和时间步长对测量得到的土壤入渗性能曲线的影响，具体估算了不同时间步长和赋值方式下，在人渗初期可能引起的入渗测量误差。

英文摘要：

The measurement of soil infiltration has long been a great concern of scientific researches and applicants. Ring infihrometeris a widely-applied instrument for soil infiltration measurement. Rain simulator and double ring methods are the common methods for measuring soil infiltration, but the disc infihrometer is widely for determination of saturated hydraulic conductivity. Numerous reports indicated that the most reliable results measured by the ring infiltrometer in the saturated hydraulic conductivity. This indicates the drawbacks of the ring infihrometer. The gaps between the ring and the soil during the ring being inserted into soil produces a passage for preferential flow to cause much higher infiltration rate. The relative long time interval between each measurement is another reason to produce higher measured infiltration rates, which is illustrated by numerical computational procedures. Both the time moment at which the computed infiltration rate is assigned to and the length of time step have their impacts on the measured soil infiltration curve. The errors caused by these factors, especially at the beginning of infiltration are illustrated.