经典BRUTSAERT模型应用于土壤水分检测的适用性探讨  

Applicability of BRUTSAERT’s model in soil moisture detection

作　　者：徐岩 吕猛[1] 桂晶晶 李君 张东霞 XU Yan;LYU Meng;GUI Jingjing;LI Jun;ZHANG Dongxia(College of Automotive Engineering,Guangdong Polytechnic of Industry and Commerce,Guangzhou 510510,China;Guangdong Laboratory for Lingnan Modern Agriculture,Guangzhou 510006,China;College of Engineering,South China Agricultural University,Guangzhou 510642,China)

机构地区：[1]广东工贸职业技术学院汽车工程学院,广州510510 [2]岭南现代农业科学与技术广东省实验室,广州510006 [3]华南农业大学工程学院,广州510642

出　　处：《农业工程学报》2023年第21期54-65,共12页Transactions of the Chinese Society of Agricultural Engineering

基　　金：广州市科技计划项目(2023A04J0126);岭南现代农业实验室科研项目(NZ2021040);现代农业产业技术体系项目(CARS-32)。

摘　　要：BRUTSAERT理论模型是非饱和土壤介质中弹性波传播的理论模型,主要用于描述声波纵波声速与农业土壤饱和度之间的关系。为探究BRUTSAERT理论模型应用在土壤水分检测中的可行性,该研究系统介绍了BRUTSAERT理论模型,分析了其在土壤含水量检测中的适用条件,并在经典BRUTSAERT模型中引入了适当的简化和假设,推导出在不同物理条件下各农业土壤的纵波声速值与土壤水分关系曲线,以及进行土壤声速测量的合适声频。结果表明,1)当声波发射器和拾音器之间的距离为0.2 m时,且声波频率范围固定在380~708 Hz之间,在任何土壤类型中BRUTSAERT理论模型都是有效的。2)前人关于BRUTSAERT模型中复合流体体积模型公式存在争议,该研究表明复合流体体积模型的定义公式不会对其结果产生大的影响。3)经典BRUTSAERT模型中土壤泊松比为固定值(0.20),然而干燥土壤和饱和土壤之间的泊松比有明显差异,对于非饱和多孔集料(如土壤和砂土),使用固定且与饱和度无关的泊松比是值得怀疑的。该研究可为BRUTSAERT理论模型在土壤水分检测领域的应用研究提供参考。The acoustic detection technology has shown its advantage in the field of soil moisture detection.The recent soil moisture detection methods mainly rely on the acoustic-based strategy,which explores the influence of the unsaturated soil moisture content on the pressure wave velocity(PWV)and the attenuation coefficient and analyzes the impact of soil moisture content on the acoustic parameters.It focuses on modeling the soil moisture content and the acoustic parameters.However,the agricultural soil holds the complicated components and has many types.Moreover,it exists the unmatched spatial-temporal distribution,causing that the structural and initial saturation of the soil is undetermined.Hence,these existing methods have challenges,giving rise to the unreliable results.The BRUTSAERT’s model is such a theoretical model that demonstrates the propagation of elastic waves in the unsaturated soil.It mainly focuses on the relationship between PWV and the soil saturation.In BRUTSAERT’s model,different soil textures result in difference of both PWV and soil saturation.Yet,it avoids the negative impact of soil structural and initial saturation on the model.Inspired by this,this study theoretically analyzed:1)the application condition with inertia viscosity coefficient of soil was less than 1,and the sound wave frequency≤708 Hz was suitable for any soil texture,which can be viewed as a superior;2)the propagation of the sound waves in soil should be approximate to a plane,and this resulted in a lower boundary.The minimum frequencies of sound waves were 796,380,266,199,and 160 Hz when the distances between the sound wave transmitter and the acoustic adapter were 0.1,0.2,0.3,0.4,and 0.5 m.Besides,the relationships between PWV and the soil moisture,with different conditions were discussed.BRUTSAERT indicated that the speed of sound wave propagation in soil relied on tree aspects:the total density of the measured soil,soil stress,and the soil particle gap parameter.This stduy proved that the three aspects were related to

关 键 词：土壤 模型 水分 声速 BRUTSAERT理论 

分 类 号：S277.9[农业科学—农业水土工程] TH837[农业科学—农业工程]