不同母质红壤坡面产流产沙特征比较

The Characteristics of Runoff and Sediment Yield of Red Soil Slope with Different Parent Materials

采用人工模拟降雨的方法,研究花岗岩、第四纪红黏土、红砂岩3种母质发育的红壤坡面产流产沙特征差异。结果表明:(1)地表产流方面,3种母质红壤地表产流时间为花岗岩红壤<红砂岩红壤<第四纪红壤,总径流量和场均产流速率均为花岗岩红壤>红砂岩红壤>第四纪红壤,其中45mm/h条件下花岗岩红壤的地表径流量为红砂岩和第四纪红壤的1.79~2.47倍,场均产流速率为后者的1.58~2.32倍。(2)地表产沙方面,在45mm/h条件下,场均泥沙浓度为第四纪红壤>花岗岩红壤>红砂岩红壤;135mm/h条件下,场均泥沙浓度为花岗岩红壤>红砂岩红壤>第四纪红壤。雨强对红壤坡面产沙的影响较大,135mm/h条件下的泥沙浓度为45mm/h条件下的8.31~11.32倍。(3)径流组成方面,3种母质红壤中壤中流所占径流比最高为第四纪红黏土发育的红壤,在2种雨强条件下为8%~44%。雨强越大,地表汇流越明显;135mm/h条件下,红壤坡面地表径流量可达到总径流的79%~90%。(4)壤中流产流方面,壤中流产流时间顺序与地表产流一致,均为花岗岩红壤<红砂岩红壤<第四纪红壤,花岗岩红壤的壤中流量最小,仅为第四纪红壤的53%~67%,峰值为后者的42%~52%;对于红壤而言,停雨后的壤中流消退过程可以用指数函数方程进行预测,在所有试验条件下,其决定系数均在0.82以上,表明具有较好的预测性。

In this paper,the artificial simulated rainfall combined with the indoor backfill soil trough was used to study the difference among the characteristics of the runoff and sediment yield in the red soil slopes with different parent meterials：granite,quaternary and red sandstone.Results showed that the order of surface runoff time of the three parent materials was granite〈red sandstone〈quaternary,averaging runoff rates and the total amount of runoff were granite〉red sandstone〉quaternary,where the runoff amount of granite red soil under 45 mm/h rainfall was 1.79-2.47 times of those of red sandstone and quaternary,and the averaging runoff rate was 1.58-2.32 times of those of the latter two.Under the rainfall conditions of 45 mm/h,the sediment concentration of the field was the quaternary〉granite〉red sandstone,while,it was granite〉red sandstone〉quaternar under 135 mm/h.The rain intensity had a greater influence on the sediment yield of red soil slope,and the sediment concentration under 135 mm/h was 8.31-11.32 times of 45 mm/h.As for the runoff composition,the proportion of interflow in runoff was highest in quaternary red soil among the materials,which was about 8% -44% in the two rain intensities.The larger rain intensity,the more obvious effect of the surface confluence,which could reach up to 79%-90% of the total runoff under 135 mm/h.The runoff time of interflow was same as that of the surface runoff：granite〈red sandstone〈quaternary,the interflow of granite red soil was smallest,accounting for only 53%-67% of the quaternary,and even 42%-52% at the peak runoff.After the rainfall,the regression of interflow could be predicted by an exponential function,all the decision coefficients were above 0.82 for all conditions,showing agood predictability.