紫色丘陵区不同弃土弃渣下垫面产流产沙试验研究

Experimental Study on Water Runoff and Sediment Yield of Different Underlying Surfaces of Waste Soil and Residue in Purple Hilly Area

采用野外放水冲刷试验法研究紫色丘陵区不同弃土弃渣下垫面产流产沙规律。结果表明:(1)不同下垫面条件的产流量、产沙量均随放水流量增大而增大;放水流量为5,10,15,20,25L/min时,产流量随时间推移均呈先增加后趋于平稳的变化,产沙量呈先增加后减小的变化,二者均存在波动现象,而产沙过程波动更为剧烈,呈现出多峰多谷特点。(2)土石比对产流量、产沙量的影响随放水流量增大而增强;相同条件下坡度越大,则产流量越大,产沙量亦越大;放水流量从5L/min增加到25L/min时,土质下垫面平均径流率、平均产沙率增加量均达到最大,而土石混合质下垫面增加量最小。(3)在产流量、产沙量与放水流量的经验方程中,25°土质下垫面产流量、产沙量增长率最大,分别为51.883,18.770,而35°土石混合质的增长率最小,分别为7.270,2.325。

Field scouring experiment was studied to explore the dynamic process of runoff and sediment generation on the underlying surfaces of waste soil and residue in purple hilly area.The results showed that：（1）Both water runoff and sediment yield were increased with increasing the flow discharge.Water runoff increased firstly and then changed stably when flow were 5,10,15,20,25 L/min,however,sediment yield increased firstly,and then decreased with the lapse of time.There was fluctuation phenomenon in both runoff and sediment yield process,and the fluctuation of sediment was stronger than runoff,presented the characteristic of multi-peak multi-valleys.（2）Soil-stone ratios’ effect on water runoff and sediment yield was increased with increase of flow discharge;both water runoff and sediment yield were increased with increasing slope gradient under the same condition.The increasing amount of the average water runoff and sediment yield rate of the underlying surface with soil reached the maximum when flow was from 5 L/min to 25 L/min,however,the soil-stone mixed was the least.（3）It could be seen from the fitting linear equations of runoff and flow discharge,the growth rate of runoff and sediment yield of the 25° underlying surface with soil reached the maximum（51.883,18.770） respectively,however,both of the 35° underlying surface with soil-stone mixed were 7.270,2.325 respectively,which were the least.