提出了一种室内土壤入渗试验装置,可以直接观测入渗过程中水分在环内土壤中的运动过程。详细描述了该装置的构成、工作原理和试验方法与过程。该装置由可以拆分的土槽和入渗环及可以透视的有机玻璃板组成。将入渗环打击进入土槽内土壤后,用钢板将环内的土壤沿径向切分成两半,移去其中一个半环及其中的土壤。用有机玻璃板封闭和固定另一半环内的土壤,用于进行土壤水分入渗过程的可视化试验,观察环式入渗仪内的水分运动过程。用采自北京的粉壤土进行入渗过程试验,同时根据水量平衡原理计算得到土壤入渗性能曲线。剖切面的湿润过程直观地显示了入渗环内水分的入渗过程存在优先流,不仅影响初始入渗过程,而且对整个入渗过程均产生影响。根据土壤湿润体所指示的土壤入渗特征将整个入渗过程划分为3个阶段:初始入渗阶段、过渡阶段和稳渗阶段。
Studying the effects of preferential flow on the infiltration process is of great importance to increase the accuracy of measurement. An experimental device was suggested to display water movement process in the soil during infiltration. The device consisted of a disassemble soil container, a halved infiltration ring and see-through container surface made of plexiglass plate. After infiltration ring was hammered into soil inside the container, the soil inside the halved ring was cut radially into two halves with a steel plate, part of soil outside the experimental part of the container was removed and a plexiglass plate was used to cover the soil inside infiltration ring for dynamic visualization infiltration experiment. Then the infiltration process in the soil profile within the ring can be observed. The structure of the device, working principle and its application methodologies were detailed. A series of infiltration experiments were conducted to demonstrate the working procedures of the device with silt loam taken from Beijing. The exemplary soil infihrability processes were computed based on the water supplied into the ring during the experiments. The dynamic process of wetted area in the soil profile inside the ring indicated that preferential flow not only influenced the initial infiltration process but also affected the total infiltration process. The whole infiltration process was divided into three stages based on the infiltration characteristics produced by wetting soil, which were initial infiltration stage, transitional stage and steady infiltration stage, respectively.