降雨条件下砒砂岩区淤积层垂直入渗特征试验研究

Experimental Study on the Vertical Infiltration Characteristics of the Silting Layer in the Siltstone Area under the Condition of Rainfall

为研究降雨条件下淤积层的降雨入渗规律及评价淤积水量,基于内蒙古达拉特旗哈他土沟砒砂岩区淤积层为研究对象,开发一套模拟降雨条件下一维土柱的入渗装置,对淤积土柱做了4组不同降雨强度下的一维垂直入渗试验,得到不同降雨强度下垂直土柱的入渗率时程曲线、浸润峰深度时程曲线及监测点体积含水率的变化规律。结果表明:1) 降雨强度对垂直土柱的入渗影响较大,当降雨强度小于土柱最小入渗能力时,入渗率等于降雨强度;当降雨强度大于土柱最小入渗能力时,入渗率时程曲线呈无压入渗、有压入渗和饱和入渗三阶段变化。2) 不同降雨强度下,土柱出现积水点和饱和点的历时不同,降雨强度越大出现积水点和饱和点的时间越短,有压入渗阶段越长。3) 在同一降雨强度下,监测点距土柱上表面越远,其体积含水率时程曲线越密集;而同一监测点,降雨强度越大,其体积含水率时程曲线越稀疏。

In order to study the rainfall infiltration law of siltation layer under rainfall condition and evaluate the siltation water quantity, a set of one-dimensional soil column infiltration device was developed based on the siltation layer in Hathagou soft rock area of Dalat Banner, Inner Mongolia. Four sets of tests were carried out to the unsaturated disturbed loess column under the different rainfall intensities. The time curves of the infiltration rate, the depth of the wetting front and the volumetric water content at the monitoring points were obtained. The rainfall intensity has great impact on the vertical infiltration in soil column. The infiltration rate equals the rainfall intensity when the rainfall intensity is less than the minimum infiltration capacity of soil column. When the rainfall intensity is greater than the minimum infiltration capacity, the curve of infiltration rate can be divided into three stages, the non-compressive infiltration, the compressive infiltration and the saturated infiltration. The moment of occurrence of the dropsy point and the saturation point are different under different rainfall intensities;the greater the rainfall intensity, the earlier the dropsy point and saturation point appear, and the longer the stage of compressive infiltration. Under the same rainfall intensity, the farther the monitoring point is from the upper surface of the soil column, the denser the time history curve of the volume moisture content is. For the same monitoring supervisor, the larger the rainfall intensity, the sparser the time history curve of volume moisture content.