基于土壤物理基本参数的土壤导气率推求模型

Soil Air Permeability Model Based on Soil Physical Basic Parameters

土壤气体传输过程复杂,影响因素众多,各因素之间相互影响与制约,且存在严重的空间变异性,其空间分布特征与变异程度同众多影响因素间关系复杂,野外条件下难以准确计算大范围区域内土壤导气率平均值。通过已经获得的土壤样本实测资料,建立土壤物理基本参数与土壤气体传输参数之间的函数模型,结果表明:偏砂质土壤的导气率与饱和度的拟合度较好,决定系数R2达0.95以上,而偏黏性的土壤结构性强,R2在0.69以上;遗传算法程序拟合系数ai、bi,R2均达0.90以上;利用此函数模型,拟合导气率与实测导气率之间的相对误差绝对值小于0.1,效果较好,验证了预测模型的适用性。提出的推求方法简化了土壤气体传输动力学参数在实际应用中繁琐的测算过程,为野外环境下简单、快速获取土壤气体传输动力学参数提供了参考。

The transport process of soil gas is pretty complex. It is influenced by many factors, which are influenced and restricted by each other. It has heavy spatial variation, and the spatial distribution and variation extent present very complex relationship with many factors. So it is very difficult to estimate the average conductivity of soil gas accurately in a large area when this happens in wild. This paper establishes a functional model about soil physical basic parameters and soil air permeability on the basis of data from measured soil samples. The results show that R2, the fitting degree of air permeability and water saturation, is up to 0.95 in sandy soil and more than 0.69 in clayed soil, because the clayed soil has higher soil structuralism. The fitting degrees of genetic algorithm system of the above two kinds of soil are more than 0.90. The absolutely relative error between the fitting air permeability and the measured air permeability is less than 0.1 by using this functional model. Furthermore, this functional model proves applicability and has good effect. The proposed method simplifies complicated calculation process of practical application and provides reference to gain soil gas transportation dynamics parameters quickly and easily.