论天然沉积砂卵石粒度分布的分形结构
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摘要
根据分形几何学理论，研究了我国黄河及陕西省的石头河、冯家山古河道河床天然沉积砂卵石的粒度成分特征，发现在双对数坐标下粒度含量与粒径之间呈直线关系，表明粒度分布具有分形结构，根据直线的斜率ｂ，由公式Ｄ＝３－ｂ可求得相应的分维。计算所得的分维在２．５５～２．８７之间，并讨论了分维与粗粒土级配的关系，提出了以分维Ｄ代替不均匀系数Ｃｕ和曲率系数Ｃｃ作为表征粗粒土级配的指标
The granularity characteristics of matural sedimentary sandy graval cobble under Yellow river and Stone River.Fengjiashan Ancient River in Shaanxi Province are studied according to the fractal geometry.It is found that there is a linear relationship between the accumulative granularity content and the grain size in log-log plot,and it's slope b can be used to calculate the relative fractal dimension D by the equation D=3-b.Results show that the D of natural sedimentary sandy gravel cobble under River changes from 2.55 to 2.87.Gorrelations between fractal dimension and gradation of coarse grained soil are discussed.It is conclued that the fractal dimension can be used as one index instead of both uniformity coefficient (C u) and coefficient of currature (C c)to describe the gradation of coarse grained soil.
The granularity characteristics of matural sedimentary sandy graval cobble under Yellow river and Stone River.Fengjiashan Ancient River in Shaanxi Province are studied according to the fractal geometry.It is found that there is a linear relationship between the accumulative granularity content and the grain size in log-log plot,and it's slope b can be used to calculate the relative fractal dimension D by the equation D=3-b.Results show that the D of natural sedimentary sandy gravel cobble under River changes from 2.55 to 2.87.Gorrelations between fractal dimension and gradation of coarse grained soil are discussed.It is conclued that the fractal dimension can be used as one index instead of both uniformity coefficient (C u) and coefficient of currature (C c)to describe the gradation of coarse grained soil.
引文
1］高安秀树，分数维，常子文等译，北京，地震出版社．1989年［2］刘松玉、方磊、陈浩东等论我国特殊土粒度分布的分形结构，岩土工程学报1993，15（1）23～30［3］水利电力部土工试验规程（SD128－84）［4］用大型直剪仪测定特大粒径砂卵石抗剪强度的试验研究，陕西省石头河水利工程指挥部、陕西省水利科学研究所，1979年6月［5］冯家山水库水电站边坡古河道砂卵石层原位抗剪试验报告，陕西省水电设计院地勘队1982．5［6］张济忠著，分形清华大学出版社1995年8月［7］冯国栋主编，土力学水利电力出版社，1986年5月
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