雨强和坡度对嵌套砾石工程边坡侵蚀特征的影响

Influence of Rainfall Intensity and Slope on Erosion of Embedded Gravel Engineering Slope

为探究不同雨强和坡度对西南高山-亚高山地区急陡、高砾石含量工程边坡土壤侵蚀的影响.采用室内模拟降雨及人工配置土壤等方法,在5种雨强(25,40,45,65,85 mm/h),5种坡度(35°,40°,45°,50°,60°)条件下进行模拟实验.研究结果表明:工程坡面产流率随着雨强的增加呈对数增加.不同雨强下坡面平均产流率变化过程随着坡度的变化差异性具有统计学意义.随着雨强的增加,同一坡面工程边坡侵蚀率明显增多.当雨强为40 mm/h时,工程坡面侵蚀率随坡度变化较小(<0.015 g/s);当雨强为65 mm/h时,同一坡面的侵蚀率随着坡度的增加而减少.工程坡面溅蚀率整体呈现出迅速增长至峰值后缓慢下降的趋势.同一边坡随着雨强的增加,坡面击溅侵蚀率在产流前和产流时都有明显的增加,不同粒径土壤增速具有明显差异,同一坡面随着坡度的增加,坡面泥沙溅蚀率存在临界值(40°~45°).降雨强度与土壤侵蚀相关性有统计学意义,不同雨强下坡度与径流过程和侵蚀过程的相关性具有明显差异性.结论:工程边坡中砾石具有增加下渗率和抗侵蚀作用,工程坡面土壤侵蚀率随降雨历时逐渐下降;坡度的增加在增大坡面流速的同时会降低坡面实际承雨面积,工程坡面土壤侵蚀率随坡度的增加呈非线性关系.

In order to explore the effect of different rainfall intensity and gradient on soil erosion of steep and high gravel engineering slope in the southwest alpine-subalpine region.By adopting the method of indoor simulation rainfall and artificial soil configuration,the five kinds of rainfall intensity(25 mm/h,40 mm/h,45 mm/h,85 mm and 65 mm/h),5 kinds of slope(35°,40°,45°,50°,60°)under the condition of simulated experiment.The results show that the runoff yield increases logarithmically with the increase of rainfall intensity.The change process of average runoff yield on slopes with different rainfall intensities was significantly different with the change of slope.With the increase of rain intensity,the erosion rate of the same slope increases obviously.When the rainfall intensity is 40 mm/h,the engineering slope erosion rate changes little with the slope(<0.015 g/s).When the rain intensity is 65 mm/h,the erosion rate of the same slope decreases with the increase of the slope.The spatter erosion rate of engineering slope shows a trend of rapid increase to the peak and slow decline.The same slope with the increase of rainfall intensity,slope splash erosion rate in front of the runoff yield and runoff yield increase obviously,soil of different size growth has obvious differences,the same slope with the increase of slope,slope sediment splash erosion rate is critical value(40°to 45°).There was a significant correlation between rainfall intensity and soil erosion.It is concluded that the gravel in the engineering slope has the effect of increasing the infiltration rate and anti-erosion,and the soil erosion rate on the engineering slope decreases gradually with the duration of rainfall.The increase of slope increases the velocity of slope and decreases the actual rain-bearing area of slope.The soil erosion rate of engineering slope is nonlinear with the increase of slope.