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该研究在湖北省秭归县花岗岩坡面下部开挖了一长度为 2 .9m ,深度为 2 .2 3～ 2 .6 0m的土壤剖面 ,经现场观察发现土管主要集中分布在B层 (花岗岩分化程度较高的层次 )和C层 (花岗岩分化程度较低的层次 )的过渡带附近 .在坡面下部坡脚部位垂直于坡长方向上 ,每米宽度大约分布有土管 5～ 7个 .近两个降雨季节的多场天然降雨及管流观测结果表明 ,只要有一定强度的降雨出现 ,土壤剖面中就会产生管流现象 .管流出现的时间、管流历时与降雨强度、降雨历时、土壤前期水分含量和土管所处的土壤剖面位置等因素有关 .土壤水分含量高、降雨强度大时 ,在降雨历时 1h前后即有管流出现 .不同土管的管流流量在一场降雨过程中具有相似的水文波形 ,即上升阶段的历时较短 ,其切线方程表现出较大的正斜率 .随降雨过程的停止 ,管流的水文波形呈缓慢的下降趋势 ,其切线方程表现出较平缓的负斜率 .管流流量对降雨雨强变化响应较为敏感 ,在一次降雨过程中 ,雨强的微小变化会导致管流水文波形的明显反映 .尤其是阵雨的出现 ,会使缓慢下降的管流流量水文波形下降得更为缓慢或转而产生小幅度的回升
In this study, a soil profile with a length of 2.2m and a depth of 2.2 ~ 2.06m was excavated in the lower part of the granite slope in Zigui County, Hubei Province. According to the field observation, it was found that the soil mainly concentrated in the B layer (granite differentiation A higher level), and a transitional zone of layer C (a layer with a lower degree of granite differentiation). There are about 5 to 7 soil pipes per meter of width at the foot of the slope at the lower part of the slope perpendicular to the length of the slope. The results of multiple natural rainfall and runoff observations in two rainy seasons show that as long as a certain intensity of rainfall occurs, the phenomenon of pipe flow will occur in the soil profile, the appearance of pipe flow, the duration of pipe flow and rainfall intensity, rainfall duration, Soil moisture content and the soil profile where the soil profile and other factors related to soil moisture content is high, when the rainfall intensity, rainfall occurred in the 1h before and after the pipe flow appears that different soil pipe flow in a rainfall process has The similar hydrological waveforms, that is, the shorter duration of the ascending phase, and the tangent equation of the hydrological wave show a larger positive slope. With the stop of the rainfall process, the hydrological waveform of the pipe flow shows a slow downward trend. The linear equation shows a gentle negative slope.The tube flow is more sensitive to the change of rainfall intensity, and the slight change of rainfall intensity will lead to the obvious reflection of tube flow hydrological waveform in a rainfall process.Especially the appearance of the shower will Slowly decreasing the pipe flow hydrological waveform drops more slowly or in turn produces a small rise