泥石流堆积区粒度分布及分形结构特征

The Characteristics of Grain-size Distribution and Fractal Features in Debris Flow Accumulation Area

为研究泥石流堆积物粒度分布及分形结构特征,通过对泥石流堆积区现场调查和颗粒分析试验,采用统计图解法和粒度分维法分析泥石流堆积区堆积特征、粒度分形结构特征及与颗粒级配的关系。结果表明:泥石流堆积区具有集中性的特点;泥石流堆积区颗粒具有很好的分形特征,堆积区中右侧分维值均值与堆积区分维值均值接近;泥石流堆积形成由晚至早分维值逐渐减小;堆积物土粒大小级配连续性较好,分维值与不均匀系数和曲率系数均呈正相关。可见泥石流堆积区粒度的相关研究对研究泥石流形成机理及指导泥石流防治具有重要的意义。

For the purpose of studying the particle size distribution and fractal structure characteristics of debris flow deposits,field investigation and particle analysis experiments were employed and the accumulation characteristics,particle size fractal structure and correlation of particle size distribution were analyzed using the statistical graphical method and particle size fractal dimension method.Results show that concentration is the nature of the debris flow accumulation area.The particles in debris flow accumulation area have good fractal characteristics.In the accumulation area,the average fractal dimension along the right axis is close to the average fractal dimension.The fractal dimension of debris flow accumulation gradually decreases from late to early stage.The size gradation of the deposits is continuous,and the fractal dimension is positively correlated with the nonuniform coefficient and curvature coefficient.This study focusing on the grain size of debris flow accumulation area is significant for the investigation of the formation mechanisms of debris flow and for the guidance of the prevention and control of debris flow.