模拟降雨条件下坡面细沟形态演变与量化方法

Evolution and quantization methods of rill morphology on the slope under rainfall simulation

为探明坡面土壤侵蚀过程中细沟的演变规律,研究细沟形态特征量化方法是非常重要的。利用室内土槽模拟降雨试验,对比了45 mm/h、87 mm/h和127 mm/h雨强下容重分别为1.30 g/cm3和1.05 g/cm3两种黄土在20°陡坡坡面细沟发育形态的差异,并分别采用分形维数、拓扑参数对细沟沟网的形态特征进行量化描述,引入地貌信息熵理论进行坡面地貌信息熵计算,然后对各量化参数的敏感性进行了分析。结果表明,分形维数作为整体性的量化参数,对描述发育成熟的细沟形态差异不够灵敏;坡面地貌信息熵能够反映侵蚀过程中侵蚀程度的变化,对细沟发育程度的描述较为灵敏;细沟沟网的拓扑特征参数较好地体现了沟网内部结构的差异,可用于描述沟网内部结构特征的较灵敏参数。

The quantitative methods of rill morphology evolution were studied,which employs the indoor soil bin rainfall simulation experiment of two bulk density of loess soil（ 1. 30 g / cm3,1. 05 g /cm3） under the rainfall intensities of45 mm / h,87 mm / h and 127 mm / h with 20° slope gradient. In the research,the fractal dimension and topological parameters were respectively calculated by different methods. Besides,the parameter of slope geomorphologic comentropy for geomorphology was also applied. Then the sensitivity of the quantization parameters was analyzed. The results show that the fractal dimension as an integrity parameter was not provided sensitively for describing the maturity rill networks. But the slope geomorphologic comentropy was a sensitive method to express erosion degree,and the topological parameters could reflect the diversity of rill network structures with preferable sensitivity.