模拟上方来水对工程开挖面冲刷的试验研究

工程开挖面是生产建设项目水土流失的主要来源之一,开挖面下垫面改变剧烈,产生的水土流失既有传统水土流失的共性,又有其自身的特殊性。其中有汇水影响开挖面占总开挖面数量的94%。通过人工开挖坡面小区及放水冲刷试验模拟汇水影响,研究上方来水条件下开挖面水土流失规律,以期为开挖边坡水土流失预测及防治提供理论基础和科学依据。结果显示:放水冲刷试验过程中基本没有初损历时,径流系数普遍偏大;侵蚀外营力放水流量、下垫面因素坡度、坡长等对开挖面土壤侵蚀均有重要的影响,均与单位面积土壤流失量呈极显著相关;新旧开挖面土壤流失量差异显著,其倍数与坡度呈极显著幂函数负相关关系;随放水流量增大,各小区径流量、单位面积产沙量均呈增大趋势;同一放水流量,不同坡长小区产流产沙差异不明显;同一放水流量,不同坡度小区之间单位面积产沙量差异显著,但径流量差异不明显。

Experimental Study on Erosion of Engineering Excavated Slope by Simulating Up-slope Runoff

Engineering excavated slope is one of the main causes of water and soil loss in production and construc-tion projects.The water and soil loss in excavated slope caused by violent changes in underlying surface has con-ventional features and also has its own unique characteristics.The excavated slope affected by up-slope runoff ac-counts for 94% of the total number of excavated slopes.In this paper the effect of up-slope runoff on the regularity of water and soil loss is researched through scouring experiments on artificial excavated slope.Results show that there is no initial abstraction duration in general,and runoff coefficient is high.Flow rate,slope gradient and slope length are in significant correlation with soil loss per unit area,indicating that these factors have important effect on the soil erosion of excavated slope.Furthermore,there is apparent difference between the soil loss of newly excava-ted slope and previously excavated slope.This difference is in significant negative power regression relation with slope gradient.With the rise of flow rate,runoff and per unit sediment yield increase accordingly.In the presence of the same flow rate,there is slight difference in runoff and sediment yield among different plots with different slope lengths,but when the slope gradient is different,there is obvious difference in sediment yield rather than in runoff.