土石混合崩积体坡面细沟径流流速试验研究

Experimental Study on Rill Runoff Velocity on the Slope of Soil-rock Mixed Colluvium

为了探究土石混合崩积体坡面细沟流速的变化特征,设置不同的流量(2,4,8,12 L/min)和砾石质量含量(0,10%,30%,50%),采用径流冲刷试验,分析崩积体坡面细沟径流流速的变化过程,研究流速对流量和砾石含量的响应。结果表明:流速在初始阶段(前5 min)减小幅度较大,随着冲刷进行,流速变化趋于平缓,二者呈幂函数关系,纯土坡面的流速衰减趋势大于含砾石的坡面;流速随着流量的增加呈幂函数增加,而随着砾石含量的增加呈对数函数递减;流量与砾石含量对流速的影响均达到显著水平,且流量的作用大于砾石含量,可用流量和砾石含量的二元对数表达流速(NSE=0.78)。研究结果深化了对崩积体坡面细沟侵蚀水动力过程的认识。

To explore the change characteristics of rill flow velocity on the soil-rock mixed colluvial deposit,the scouring experiment was carried out.Four flow rates(2,4,8,12 L/min)and four gravel mass contents(0,10%,30%and 50%)were set up.The change characteristics of rill flow velocity on the soil-rock mixed colluvial deposit were analyzed,and the response of flow velocity to flow rate and gravel content was studied.The results showed that the velocity decreases exponentially with scouring time,and the velocity attenuation trend of pure soil is larger than that of gravel-containing slope.The velocity of flow increased as a power function with the increase of flow velocity and decreased as a logarithmic function with the increase of gravel content.The effect of flow velocity and gravel content on flow rate was significant,and the effect of flow rate was greater than that of gravel content.Flow rate can be expressed by binary logarithm of flow rate and gravel content(NSE=0.78).The research results deepen the understanding of hydrodynamic process of rill erosion on colluvial deposit slope.