黄土粒度分维在公路自然区划中的应用探讨  

The Application of Loess Grain Size Fractal Dimension in Regional Classification by Natural Features for Highways in China

作　　者：侯春梅[1,2] 刘小伟[1] 梁收运[1] 谌文武[1] 

机构地区：[1]兰州大学土木工程与力学学院,甘肃兰州730000 [2]中国科学院资源环境科学信息中心,甘肃兰州730000

出　　处：《中国沙漠》2009年第5期828-834,共7页Journal of Desert Research

基　　金：交通部西部交通建设科技资助项目(2001-318-000-18)资助

摘　　要：针对当前黄土地区公路自然区划宏观程度高、实际难应用等问题，研究新的区划方案、寻找理想的区划指标意义重大。以分形理论为基础，分析了甘肃黄土粒度分布的分形结构特征。结果显示，黄土具有良好的统计自相似性，其分维值介于2.15-2.705之间；黄土的粒度分维值可定量表征黄土的物理、力学和水理性质及差异，即黄土的粒度分维值越大，其干密度、比表面积、粘聚力、内摩擦角越大，微、小孔隙含量越高，但其平均孔径、孔隙比、湿陷系数和渗透系数越小，其工程地质性质愈稳定；在空间上，黄土粒度分维值存在显著的区域性变化规律，反映了甘肃黄土地区二级公路自然区划的5个二级区的差异。认为黄土粒度分维值可作为公路自然区划的主要指标之一，参与三级区的划分，为公路工程的设计、施工提供科学依据。Highway construction greatly develops in China nowadays, but the regional classification of high-ways is highly macroscopical and the classification standards are hard to employ, especially in the loess areas of China. The study aims to search for the idea classification scheme and standards. Results of analysis on the fractal dimension （D） of the grain size of loess in Gansu province show that loess has close statistical self-correlation, with fractal dimension values from 2.15 to 2. 705. The fractal dimension （D） of soil grain size can not only reflect the sediment environment but also decide the soil physical, mechanical and hydraulic properties. That is, the higher fractal dimension the higher dry density is, also the higher specific surface area, the higher soil cohesion and the higher internal friction angle is; simultaneously, the more micropores are. Whereas, the higher fractal dimension indicates the smaller average aperture, smaller void ratio, smaller collapsibility coefficient and smaller permeability coefficient, thus the stable engineering geology nature of soil. Analyzing results also show that the fractal dimension （D） of loess grain size has obvious spatial variation law, well reflecting the differentiation among the five sub-regions of Gansu second-grade highway classification. All these suggest that the parameter of fractal dimension （D） of the soil grain size could serve as an index for highway regional classification same as the indexes of topography, landform, hydrology, climate and etc.

关 键 词：黄土 分维 粒度分布 公路自然区划 

分 类 号：P642[天文地球—工程地质学]