摘 要 ：以三峡库区王家桥小流域为研究区，通过野外调查选择了5个典型路段，在1.0 mm min-1模拟降雨条件下研究了土质道路降雨-径流-泥沙关系。结果表明，土质道路被高度压实，但使用强度和管护方式差异致使容重、路面浮土、杂草盖度、饱和导水率等差异显著。土质道路仅需1~3 mm降雨就能产生地表径流，7~10 mm的降雨使径流趋于稳定，径流系数超过60%，特别是车流量较大干道的径流系数超过70%，平均和峰值径流量达0.69 mm min-1和0.84 mm min-1。土质路面大量浮土致使初始径流含沙量高，然后快速下降并趋于稳定。由于路面浮土量大和在降雨过程中能形成人工细沟的车辙等导致较大车流量干道的土壤流失率是其它路段3~4倍。土质道路的容重和路面浮土与径流系数和土壤流失量呈显著正相关，饱和导水率则呈显著负相关；路面杂草能显著减少径流，防治路面侵蚀。
Abstract:Unpaved roads are common in mountainous areas. This study examined the characteristics of surface runoff and sediment production from unpaved roads in Wangjiaqiao watershed of the Three Gorges Area of China using a simple portable rainfall simulator. 5 road segments were selected for rainfall simulation. Fifteen rainfall simulation experiments with an intensity of 1.0 mm min-1 were carried out on 5 road segments. Cumulative rainfall to runoff was recorded 1-3 mm. The runoff rate generally increased quickly and reached steady level in the first 7-10 min. The runoff coefficient was above 60%, with higher than 70% on the intensively used road segment. The average runoff rate and peak runoff rate were 0.69 mm min-1 and 0.84 mm min-1, respectively. The greatest erosion was found on the intensively used road, where sediment yield average was 14.38 g L-1 and soil loss rate was 12.22 g m-2 min-1. The sediment concentration increased in the first 1-4 min from the beginning of the rainfall and then decreased steadily due to the loss of fine soil surface particles and porosity changes. The soil loss rate of the intensively used road was 3 and 4 times higher than those from the infrequent traffic road. There is a relationship between sediment yield and the intensity of road usage, due to the creation of artificial rills by vehicles in the rainy periods. Statistical analysis shows that bulk density, saturated hydraulic conductivity, and dust on road surface have significant effects on runoff and soil loss. Stone cover may increase surface runoff, but vegetation cover is very effective in erosion control and runoff reduction.