乌拉山废弃矿区坡长对客土坡面产流产沙与沟蚀特征的影响

Effects of Slope Length on the Characteristics of Runoff and Sediment Yield and Gully Erosion on Alien Soil Slopes in the Abandoned Mining Area of Wula Mountain

为研究不同坡长客土坡面产流产沙及沟蚀特征差异变化,通过设计2个坡度(15°,20°)下不同坡长(2,4,6,8,10 m)的野外径流小区进行冲刷试验。结果表明:(1)初始产流时间变化范围与产流停止时间均随坡长增加而增大,产流率初期快速增加,达到初次峰值后呈现不规律波动,累积产流量随坡长增加而增多;产流率、累积产流量与坡长、产流时间及其交互作用呈极显著相关(p<0.01),累积产流量在2种坡度下均与坡长、产流时间呈幂函数相关。(2)产沙率初期快速增加,达到初次峰值后随冲刷时间逐渐下降,其均值随坡长增加而增大,总累积产沙量随坡长增加而增多;累积产沙量与坡长、产流时间的交互作用呈极显著相关(p<0.01),累积产沙量在2种坡度下均与坡长、产流产流时间呈幂函数相关。(3)侵蚀沟平均横截面积自顶端呈现沿坡面减小,以及减小—增加—再减小2种趋势。累积产沙量与估算沟蚀量具有极显著相关性(p<0.01),其差值随坡长的增加而增加,其比率随坡长增加呈先上升后下降趋势,最大值出现在6 m坡长。研究结果为矿山修复客土坡面水土流失防治及侵蚀模型建立提供技术支持。

In order to study the variation of runoff and sediment yield and gully erosion characteristics on alien soil slopes with different slope lengths in the abandoned mining area of Wula mountain, scouring tests were conducted by designing field runoff plots with different slope lengths(2, 4, 6, 8 and 10 m) under two slope gradients(15° and 20°). The results showed that:(1) The variation range of initial runoff generation time and runoff generation stop time both increased with the increasing of slope length. The runoff rate increased rapidly at the beginning and fluctuated irregularly after reaching the initial peak value. The cumulative runoff increased with the increasing of slope length. The runoff rate and cumulative runoff were highly significant(p<0.01) correlated with slope length and runoff generation time and their interaction, and cumulative runoff showed a power function correlation with slope length and runoff generation time under the two slope gradients.(2) The sediment rate increased rapidly at the beginning and reached the initial peak value, then decreased gradually with the increasing of scouring time, and its mean value increased with the increasing of slope length, and the total cumulative sediment yield increased with the increasing of slope length. The cumulative sediment yield was significantly correlated with slope length, runoff generation time and their interaction(p<0.01), and the cumulative sediment yield was related to the slope length and runoff generation time as a power function under the two slope gradients.(3) The average cross-sectional area of erosion ditch from the top showed two trends of decreasing along the slope and decreasing-increasing-decreasing again. The cumulative sediment yield and the estimated gully erosion volume had a highly significant correlation(p<0.01), and their difference increased with the slope length, and their ratio tended to increase firstly and then decrease with the increasing of slope length, and the maximum value appeared at 6 m slope length. The research results could provide technical support for erosion control and erosion model establishment of alien soil slopes in mine rehabilitation.