土壤水分特性曲线的分形模拟  

Modeling soil water retention curve with fractal theory

作　　者：黄冠华[1] 詹卫华[1] 

机构地区：[1]中国农业大学水利与土木工程学院,北京100083

出　　处：《水科学进展》2002年第1期55-60,共6页Advances in Water Science

基　　金：国家自然科学基金项目 ( 5 98790 2 8) ;霍英东青年教师基金 ( 71 0 2 7)~~

摘　　要：应用Menger海绵结构模型 ,推导出包含有分形维数的土壤水分特征曲线的解析模型 ,该模型与Brook Corey ( 1 96 4 )及Campbell ( 1 974 )经验模型的结构相似。通过对不同地区所采集的1 0种土壤样本利用压力薄膜仪实测得到水分特性曲线资料反求得到相应的分形维数 ,分析了分形维数与土壤质地、结构之间的关系 ,结果表明分形维数随土壤粘粒含量的增大而增大 ,随砂粒含量的增大而减小。同时对土壤水分特性曲线模型的分形维数与基于质量的土壤颗粒分布分形维数进行了比较 ,结果表明 ,两者十分接近 ,而且具有良好的线性相关关系。根据上述关系 ,利用易测得的土壤粒径分形维数结合所推导的解析模型 ,对土壤水分特性曲线进行了预测 ,预测值与实测值具有良好的一致性。A three-dimensional fractal model for soil water retention curve (SWRC) is derived with Menger Sponge model on the basis of Tyler and Wheatcrafts'theory, which is related to the intrinsic nature of the fractal porous structure. The fractal dimension is calculated with experimental data for soil retention curve of ten soils. And the fractal dimension of SWRC is then compared to the fractal dimension of particle-size distribution (PSD) which is calculated on the basis of accumulative mass distribution of soil particles. The results indicate that the fractal dimension of SWRC increases with clay content but decreases with sand content, and the fractal dimension of SWRC shows slightly difference and is linear related to the fractal dimension of PSD. This implies that the soil water retention curve can be predicted by the power-law function incorporating with the mass based fractal dimension of PSD. It can be seen that the predicted soil water retention curve agrees well with the measured data.

关 键 词：土壤 水分 分形维数 颗粒分布 

分 类 号：S152.7[农业科学—土壤学]