Fractal Model for Predicting the Curves of Unsaturated Soil Water Retention along the Mainstream of the Tarim River
Fractal Model for Predicting the Curves of Unsaturated Soil Water Retention along the Mainstream of the Tarim River
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发表时间：
2004
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通讯作者：
Z. Zhan
中科院分区：
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作者：
Z. Zhan
大量研究表明，土壤粒径和重量的分布是分形的，一般用分形几何来描述。本文对塔里木河干流沿线土样地采集的6个土壤样品进行了分析。利用 Van Genuchten 模型建立了预测非饱和土壤持水曲线的分形模型。利用塔里木河干流6种不同土壤土壤保水曲线的试验数据，计算了土壤保水曲线的分形维数。并将土壤保水率曲线的分维数与根据土壤颗粒累积质量分布计算得到的土壤粒径分布分维数进行了比较。结果表明，随着粘土含量的增加或砂含量的减少，土壤保水性和土壤粒径曲线的分形维数逐渐增大。土壤持水量曲线的分形维数与粒径分布曲线的分形维数略有不同，且分形维数之间存在线性关系。利用分形模型对土壤保水曲线进行了预测，结果表明，土壤保水曲线的模拟值与实测值较为接近。这表明土壤保水曲线可以用分形模型来预测。
Numerous studies have revealed that the distribution of soil particle sizes and weights is fractal, which are generally described with fractal geometry. In this paper, an analysis on six soil samples sampled from the soil plots along the mainstream of the Tarim River is carried out. A fractal model for predicting the curves of unsaturated soil water retention is developed with Van Genuchten model. The fractal dimensions of the curves of soil water retention are calculated with the experimental data for soil water retention curves of six different kinds of soils along the mainstream of the Tarim River. And the fractal dimensions of the curves of soil water retention are compared with the fractal dimensions of distribution of soil particle sizes, which are calculated on the basis of accumulative mass distribution of soil particles. The results show that the fractal dimensions of the curves of soil water retention and soil particle sizes increase gradually with the increase of clay content or decrease of sand content. The fractal dimensions of the curves of soil water retention are slightly different form that of particle size distribution, and there is a linear relation between their fractal dimensions. The curves of soil water retention are predicted with the fractal model, and the results show that the simulated values of soil water retention curves are quite similar to the observed values. This reveals that the curves of soil water retention can be predicted with the fractal model.