含砾石锥状工程堆积体坡面径流侵蚀特征

Characteristics of Slope Runoff Erosion on the Cone Shaped Engineering Accumulation with Gravel

以关中地区的重质土壤为试验材料,利用自制的堆积平台模拟散乱锥状工程堆积体的堆积过程及形态建造实体模型,在人工模拟降雨的条件下,研究了4个降雨强度下(1.0,1.5,2.0,2.5mm/min)不同砾石质量分数(0,10%,20%,30%,40%)锥状工程堆积体坡面的径流产沙特征。结果表明:(1)径流率和流速随时间呈现出先快速增加后缓慢增长至稳定的变化趋势,雨强和砾石含量对径流率和流速均有显著性影响,其中雨强对两者的贡献率较大,起决定性作用;(2)平均径流率和平均流速随雨强的增大而增加,与雨强呈极显著的正相关关系,随砾石含量的增加而减小,与砾石含量呈极显著的负相关关系;(3)雨强为1.0mm/min时,侵蚀速率先快速增加后逐渐趋于稳定;雨强≥1.5mm/min时,侵蚀速率呈持续增长的变化趋势,雨强为2.0,2.5mm/min时,在降雨中后期侵蚀速率突变式增加;(4)侵蚀总量随雨强的增大呈指数型增加的趋势,随砾石含量的增加呈负对数型减小的趋势。

In order to study the characteristics of slope runoff and sediment yield on the cone shaped engineering accumulation,a self-made platform was used to simulate the three-dimensional pyramidal engineering accumulation,and indoor artificially simulated rainfall experiments with different rainfall intensities（1.0,1.5,2.0 and 2.5 mm/min）were carried out.The heavy soil in Guanzhong area was used as test material,and different mass percentages of gravel（0,10%,20%,30%,and 40%）were set.The results showed that：（1）The runoff rate and flow velocity increased rapidly first and then slowly increased to the stable with the time trend,the rainfall intensity and gravel content both had significance influence on runoff rate and flow velocity,and the rainfall intensity played a decisive role;（2）The mean runoff rate and flow velocity had very significant positive correlation with rainfall intensity and very significant negative correlation with gravel concentration;（3）When the rainfall intensity was 1.0 mm/min,the erosion rate first increased rapidly and then tended to be stable,when the rainfall intensity was greater than 1.5 mm/min the erosion rate showed a trend of continuous growth,while when the rainfall intensities were 2.0 and 2.5 mm/min,the erosion rate increased abruptly in the middle and late stages of rainfall;（4）The total amount of erosion showed an exponential increase trend with the increasing of rainfall intensity and a logarithm decrease trend with the increasing of gravel content.