基于一维水平入渗确定土壤水分扩散率的迭代法  

Iterative Method for Determining Soil Water Diffusivity Based on One-dimensional Horizontal Infiltration

作　　者：熊臻 龙平[1] 王观石[1,2] 黄颖 罗嗣海[2] 熊紫彦 XIONG Zhen;LONG Ping;WANG Guanshi;HUANG Ying;LUO Sihai;XIONG Ziyan(School of Civil and Surveying Engineering,Jiangxi University of Science and Technology,Ganzhou,Jiangxi 341000,China;Jiangxi Provincial Key Laboratory of Environmental Geotechnical and Engineering Disaster Control,Ganzhou,Jiangxi 341000,China)

机构地区：[1]江西理工大学土木与测绘工程学院,江西赣州341000 [2]江西省环境岩土与工程灾害控制重点实验室,江西赣州341000

出　　处：《土壤》2024年第6期1371-1380,共10页Soils

基　　金：江西省自然科学基金项目(20212BAB211012);国家自然科学基金项目(52364015)

摘　　要：本文先采用Van Genuchten模型(VG)描述土壤水分扩散率,预设模型参数,再通过Philip法计算不同体积含水率对应的Boltzmann参数(θ-λ数据),与θ-λ数据的测试值进行比较,进而采用内点法优化确定模型参数,以此建立确定土壤水分扩散率的迭代法,并通过Hydrus-1D模拟和文献数据验证方法的可行性。结果表明:当体积含水率存在10%以内的测试误差时,土壤水分扩散率计算结果的决定系数均能大于0.9950。对于分析体积含水率随时间变化的数据(θ-t数据)时,受边界效应影响的临界含水率对计算结果影响较小,即使临界含水率小于0.280 m^(3)/m^(3),其计算结果的决定系数也大于0.9970。与现有方法进行比较发现,当测试数据为θ-t数据时,本文建立的方法可以弥补现有方法难以准确确定高体积含水率区间的土壤水分扩散率的缺点。由此可见,本文建立的方法可以准确确定土壤水分扩散率,且受测试误差和临界含水率的影响较小,可以为非饱和水分运动的研究提供可靠参数。This study employed the VG model to characterize soil water diffusivity,predefined model parameters,and utilized the Philip method to calculate Boltzmann parameters corresponding to varying water content(θ-ldata).Compared to the test values,the interior point method was used to determining model parameter.Consequently,an iterative method for determining soil water diffusivity was proposed.The applicability of the proposed method was verified through the Hydras-1D simulation and existing literature data.Results revealed that with a testing error of less than 10%in water content,the determination coefficients of the calculated soil moisture diffusivity consistently exceeded 0.9950.When analyzing data on temporal water content variations(θ-t data),the critical water content which was influenced by boundary effects exerted minimal impact on the calculated outcomes,and even if it was below 0.280 m^(3)/m^(3),the determination coefficient of the calculated results remained above 0.9970.By contrast with existing methods,this method can offset difficulties of accurately determining soil water diffusivity in high water content ranges when the test data isθ-t data.Therefore,it is evident that the proposed method can accurately determine soil water diffusivity,with minimal influence from testing errors and critical water content.These above findings can provide reliable values for soil water diffusivity,aiding in the simulation of soil water movement.

关 键 词：RICHARDS方程 Hydrus-1D模拟 水平入渗 土壤水分扩散率 Philip法 

分 类 号：S152.7[农业科学—土壤学]