中文摘要：

提出一种环式入渗试验装置,可以在入渗进行一段时间后,通过观测初始入渗水在土壤剖面的分布,估量初始入渗的过程。该入渗环为可拆分的两个半环,以便通过观察入渗水分在土壤剖面的分布估计初始入渗特性。论述了环的构成和测量过程与方法。同时用有机玻璃圆管装填土样,对比观察模拟真实一维入渗过程。用采自北京的粉壤土和该试验装置进行土壤入渗试验。试验分为3种入土打击能量：1、2、4 kg铁锤,自1 m高处自由落体打击入渗环入土。土壤干体积容积密度分别为：1.2、1.3、1.4 g/cm^3。每次试验均向环内注入2 L水,每组试验进行2次重复。入渗环内土壤湿润土体表明,实际发生的土壤入渗为由环壁向环内土壤的径向入渗和由地表向下垂直入渗构成,环壁与土壤剖面间产生的优先流极大地影响了初始土壤入渗率的测量精度。在初始入渗阶段,由环壁向土体的水平径向入渗宽度和由地表向土体的垂直入渗深度近似相等,垂直入渗深度是水平径向入渗宽度的1.001倍。环式入渗仪测得的土壤初始入渗率为模拟真实一维入渗率的3.3倍。研究结果可为环式入渗仪测量结果的评估提供参考。

英文摘要：

The initial soil infiltration rate affects and determines rainfall runoff,hydrological processes and soil erosion process.A new experimental method and device were suggested to test the initial infiltrability of soil under ring infiltrometer.The water distribution in the soil profile as made by the initial infiltrated water was visually observed and the initial process of soil infiltration was estimated.The specially constructed ring could be disassembled into two halves so as to conveniently observe the distribution of the infiltrated water.The detailed structure of the special designed ring and its application methodologies were detailed.An infiltration ring made of plexiglass was used to comparatively observe the1-D infiltration process with refilled soil of the same density.The diameter of the disassemble ring was35 cm,as the standard.A series of infiltration experiments were conducted with silt loam taken from Beijing.The experiment involved three soil bulk densities,1.2 g /cm^3,1.3 g/cm^3,and 1.4 g/cm^3 and three hammering energy levels,determined by the weights of hammers of 1 kg,2 kg,4 kg,freely falling down from 1 m height.Two liters of water were used for the observations in every experiment,with two replicates.The wetted soil volume in the ring showed that the actually wetted soil column by the infiltrated water consisted of the radial /horizontal infiltration caused by the gaps between the ring wall and soil and the vertical infiltration from the ground surface.The preferential flow between the ring wall and the soil significantly influenced the accuracy of the measured infiltration rate.The errors increased with the increase of soil bulk density.The observed initial infiltration,in terms of the radial infiltration width and the vertical infiltration depth was approximately equal.The depth of vertical infiltration was 1.001 times of radial infiltration width.The initial infiltration rate measured was 3.3 times of the simulated 1-D initial infiltration rate.This study will supply a method for assessing