非饱和土壤水分水平运动分形Richards模型的实验验证和分析  

EXPERIMENTAL VERIFICATION AND ANALYSIS OF FRACTAL RICHARDS’EQUTATION MODEL IN DESCRIBING HORIZONTAL WATER TRANSPORT IN UNSATURATED SOIL

作　　者：樊祥旗 郭观林[2] 孙洪广[1] 郝笑笑 FAN Xiang-qi;GUO Guan-lin;SUN Hong-guang;HAO Xiao-xiao(State Key Laboratory of Hydrology Water Resources and Hydraulic Engineering,The College of Mechanics and Materials,Hohai University,Nanjing 210098,China;Chinese Research Academy of Environmental Sciences,Beijing 100012,China)

机构地区：[1]河海大学力学与材料学院水文水资源与水利工程科学国家重点实验室,南京210098 [2]中国环境科学研究院,北京100012

出　　处：《环境工程》2019年第12期212-217,共6页Environmental Engineering

基　　金：国家自然科学基金(11572112,11772121,11811530069);水文水资源与水利工程科学国家重点实验室开放研究基金面上项目(2017490911)

摘　　要：合适的数学模型在探究非饱和土壤水分运动规律的中起着极其重要的作用。基于水平土柱非饱和土壤中水分运动实验,利用实验中观测到的非Boltzmann尺度律现象,对影响非Boltzmann尺度律参数大小的因素进行分析整理。在扩散系数与含水率呈指数函数关系条件下,采用分形导数Richards模型(FRE)对水平土柱非饱和土壤水分运动实验中含水率的空间分布及含水率穿透曲线结果进行模拟。结果表明:土壤颗粒级配不均性、较高的实验水头等会增大非Boltzmann尺度律参数;无论非Boltzmann尺度律参数>0.5还是<0.5,分形导数Richards模型的拟合效果均优于经典Richards模型(CRE)。因此,分形导数Richards模型对水分运动规律的描述是有效的,可以为非饱和土壤中水分运动模拟提供模型参考。Appropriate mathematical model plays an important role in exploring water transport in unsaturated soils.Based on the laboratory scale experiments of water transport in horizontal unsaturated soil column,the non-Boltzmann scale law observed in the experiment was used to analyze the affecting factors of non-Boltzmann scale law.When we assumed the diffusion coefficient was an exponential function,the water content snapshots and breakthrough curves in the horizontal unsaturated soil column,could be well characterized by using fractal Richards’equation model(FRE).The fitting results showed that the index of non-Boltzmann scale law increased with the heterogeneity of soil grains and the head.The experimental data fitting results illustrated that the fractal Richards’equation model was better than the classical Richards’equation models(CRE),regardless the non-Boltzmann scale law parameter was higher or less than 0.5.In conclusion,the fractal Richards’equation model could well capture the water transport process,which could be regarded as an available method for the simulation of water transport in unsaturated soil.

关 键 词：非饱和土壤 水分运动 非Boltzmann尺度律 穿透曲线 分形导数Richards模型 

分 类 号：S152.7[农业科学—土壤学]