赣东北红壤区高速公路边坡土壤侵蚀规律

Erosion Rule of Expressway Side Slope Soil in Red Soil Region of Northeast Jiangxi Province

针对红壤区公路边坡土壤侵蚀规律不明晰的问题,以赣东北地区典型高速公路边坡为研究对象,设置坡面径流小区,通过人工降雨模拟试验,数据统计,分析了赣东北红壤区高速公路边坡在降雨、土壤容重、坡度因子影响下的土壤侵蚀规律。结果表明:在不同雨强下,土层松散边坡的土壤侵蚀速率与雨强变化的趋势呈正相关,压实边坡的土壤侵蚀速率增加的幅度较小;小雨强条件下边坡土壤容重对土壤侵蚀速率的影响较为显著,土壤侵蚀量随容重的增加而增加,当雨强大于1.74 mm/min时,土体表层出现超渗产流,侵蚀速率随容重的增大而减小;坡度对土壤侵蚀速率的影响是随坡度增大而增加,容重对侵蚀产沙过程的影响要比坡度因素大;在红壤区高速公路边坡生态治理过程中,应对坡体进行压实增大坡面容重,降低坡面坡度,以此来降低土壤侵蚀速率,减小水土流失量。

In view of the unclear rule of soil erosion of highway slope in red soil region,taking the typical highway slope in northeast Jiangxi as the study object,setting up the slope runoff plot,through the artificial rainfall simulation test and the data statistical,the rule of soil erosion of expressway slope under the influence of rainfall,soil bulk density and slope gradient is analyzed in the red soil region of northeast Jiangxi province.The result shows(1)that under different rainfall intensities,the soil erosion rate of loose soil slope is positively correlated with the change of rainfall intensity;(2)under the condition of light rain intensity,the influence of soil bulk density of slope on soil erosion rate is obvious,and the soil erosion amount increases with the increase of soil bulk density when the rainfall intensity is more than 1.74 mm/min,the surface layer of soil surface appears the over percolation runoff,and the erosion rate decreases with the increase of bulk density;(3)the effect of slope on soil erosion rate increases with the increase of slope,and bulk density has more influence on the process of soil erosion and sediment yield than that of slope;(4)in the process of ecological control of expressway slope in red soil region,it is necessary to increase the bulk density of slope and decrease the slope gradient,so as to reduce the rate of soil erosion and the amount of soil and water loss.