长江三峡花岗岩坡面管流产流特性研究

Property of Pipeflow Production on Granite Slope in Three-Gorge of Yangtze River

含有大孔隙的土体 ,如花岗岩风化壳及其上形成的土层水分运动规律并不遵从达西定律 (Darcy L aw) ,大孔隙中运动的水流称为管流 (pipe flow)。在花岗岩地区 ,由于管流的普遍存在 ,从土壤剖面流出的水量远远超出在达西法则定义下流出的水量。为研究土壤水分渗透中非遵从达西定律的土管 (大孔隙 )管流运动规律 ,在位于长江三峡的湖北省秭归县花岗岩坡面进行了管流流量、坡面渗流、地表径流和降雨过程等项目的观测和研究。发现管流在该地区是一种普遍存在的现象 ,管流过程中的水分运动不遵从达西定律 ,其流量在坡面渗流中占的比重约为 10 %～ 30 % ,土管在土壤剖面中所占面积虽然很小 ,但其水分通量远大于相同降雨条件下的土壤剖面水分渗透通量。

The water movement in soil with macropores,for example soil formed from granite weathering crust and above it, doesnt follow Darcy Law. Water flow in macropores is called pipe flow. Because of the universal occurrence of pipe flow, in the granite region, water discharge from soil cross section is much larger than that following Darcy Law(Tsukamoto,1988). In the lower part of the slope in the granite region of Zigui county, Hubei Province, China, we observed discharge of pipe flow, infiltration, surface flow and the process of rainfall in order to study the law applied to pipe flow in macropores. We found that pipe flow is occurred universally in this region. Water movement in soil pipes doesnt follow Darcy Law. Discharge of pipe flow is 10%～30% of the infiltration of the slope.