公路建设引起的人为加速侵蚀对生态环境造成很大影响,为摸清道路边坡的侵蚀规律,在青藏公路边坡布设了自然径流观测小区,降雨过后进行采样,获得径流深和侵蚀模数数据。对所得数据整理分析表明:(1)次径流深、次侵蚀模数与降雨量和降雨强度的乘积有很好的线性相关,相关系数分别为0.802和0.554。次径流深与次侵蚀模数之间的相关系数达到0.771;(2)产流产沙随坡长增加有减少的趋势,但其规律还有待进一步研究;(3)随着时间的推移,产流产沙有所下降,小区坡面的干扰得到了恢复,因此,时间是公路边坡水土流失的重要影响因素;(4)公路边坡的年侵蚀模数,包括降雨侵蚀和冻融侵蚀,共计11991.41 t/km2,属于极强度侵蚀。
There is extremely fragile ecosystem in the Tibetan Plateau in China because of its severely natural conditions. Once destroyed, it is very hard to get recovered. Especially it is main headwaters for famous rivers such as the Yangtze River, the Yellow River, etc. However, in recent years, China government has been conducting great road construction in the area. These road constructions would cause erosion more and more serious, and sediment from road would destroy aquatic ecology. Now it is necessary to find road erosion principles so as to take scientific and effective measures to reduce or control road erosion adverse effects on aquatic ecology, so we took two years to observe by setting up natural runoff plots on road sideslope (fill slope) of Qinghai-Tibet highway. When each rain was over, we sampled and attained runoff depth and soil loss. Siphonal Automated Record Rain Gauge recorded the rainfall process. After analyzing these data, we get the following results: (1) The product of rainfall and average rainfall intensity (PI) is well correlated to both runoff depth and sediment yield per rainfall event. In addition, the correlation coefficient between runoff depth and sediment yield per event also can get to 0.771. (2) Runoff depth and sediment yield decrease as slope length increases. (3) Runoff and sediment decrease over time, and the disturbance to plots got recovered during the past two years, so time is a very important factor to affect road erosion. (4) According to the existing datasets, soil losses of road sideslope is 119.91 t /(ha穉), including rainfall erosion and freezing and thawing erosion. The results of this study show us that the idea of USLE (Universal Soil Loss Equation) in America can be used for road erosion prediction after revised under specific conditions. Overall, this study explored the factors influencing road erosion and how they affect, so it is significant not only to make road erosion prediction model, but also to protect environment especially for watershed ecology.
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