基于地质雷达方法研究非饱和黄土的介电性能,以及地质雷达波在空气-黄土界面中的反射机理及规律,利用地质雷达等对非饱和黄土相对介电常数与电导率进行系统试验研究,分析了黄土混合相对介电常数与其固、气、液各相的相对介电常数的内在关系;提出不同压实度与含水率与黄土相对介电常数的数理关系,以及不同地质雷达天线频率对黄土含水率-相对介电常数物理关系的影响规律。分析结果表明:非饱和黄土相对介电常数与黄土含水率和压实度呈正相关的数理关系;相同的黄土试样测试的相对介电常数与地质雷达天线主频的大小正相关;不同含水率的非饱和黄土界面反射数值模型表明,含水率越大,地质雷达回波强度越大。以上结论对非饱和黄土工程的地质雷达法探测工作具有指导作用。
Abstract
The dielectric property of loess and the reflection mechanism and law of ground penetrating radar (GPR) wave are studied in this article. Through tests on the relative permittivity and conductivity of unsaturated loess, the inner relation between relative permittivity and three phases (gas, liquid, and solid) is analyzed. Moreover, the mathematical-physical relations of relative permittivity versus compaction degree and moisture content are obtained. The influence of GPR antenna frequency on the moisture content-permittivity relation is also analyzed. Results suggest that relative permittivity of unsaturated loess is positively related with moisture content and compaction degree; given the same loess sample, relative permittivity is positively related with antenna frequency. In addition, the interface reflection numerical model of relative permittivity versus moisture content is built, indicating that echo intensity of GPR grows with the increase of moisture content. The above conclusions are of guiding significance for GPR detection of unsaturated loess engineering.
关键词
非饱和黄土 /
地质雷达 /
相对介电常数 /
含水率 /
时域有限差分方法 /
界面反射
Key words
unsaturated loess /
ground penetrating radar /
relative permittivity /
moisture content /
finite-different time-domain forward /
interface reflection
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
参考文献
[1] 赵永虎,刘 高,毛 举,等.基于灰色关联度的黄土边坡稳定性因素敏感性分析[J].长江科学院院报, 2015, 32(7): 94-98.
[2] 孙 强,赵俊平,王媛媛,等.基于摩擦学原理的土质边坡稳定性分析[J].长江科学院院报,2008,25(5):111-114.
[3] TRAN A P, VANCLOOSTER M, ZUPANSKI M. Joint Estimation of Soil Moisture Profile and Hydraulic Parameters by Ground-Penetrating Radar Data Assimilation with Maximum Likelihood Ensemble Filter[J]. Water Resources Research, 2014, 50(4): 3131-3146.
[4] THRING L M, BODDICE D, METJE N. Factors Affecting Soil Permittivity and Proposals to Obtain Gravimetric Water Content from Time Domain Reflectometry Measurements[J].Canadian Geotechnical Journal,2014,51(11): 1303-1317.
[5] MARUYAMA Y, NUMAMOTO Y, SAITO H, et al. Complementary Analyses of Fractal and Dynamic Water Structures in Protein-Water Mixtures and Cheeses[J]. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2014, 440: 42-48.
[6] URBAN T M, LEON J F, MANNING S W, et al. High Resolution GPR Mapping of Late Bronze Age Architecture at Kalavasos-Ayios Dhimitrios, Cyprus[J]. Journal of Applied Geophysics, 2014, 107: 129-136.
[7] 巨兆强. 中国几种典型土壤介电常数及其与含水量的关系[D]. 北京:中国农业大学, 2005.
[8] 孙宇瑞.非饱和土壤介电特性测量理论与方法的研究[D]. 北京:中国农业大学, 2000.
[9] 胡庆荣. 含水含盐土壤介电特性实验研究及对雷达图像的响应分析[D]. 北京:中国科学院研究生院, 2003.
[10]朱安宁, 吉丽青, 张佳宝, 等. 不同类型土壤介电常数与体积含水量经验关系研究[J]. 土壤学报, 2011, 48(2): 263-268.
[11]LORENTZ H A. Electromagnetic Phenomena in a System Moving with Any Velocity Smaller than That of Light[M]. New York: Springer, 1937.
[12]葛德彪. 电磁波理论[M]. 北京:科学出版社, 2011: 56-92.
[13]曾昭发, 刘四新, 冯 晅, 等. 探地雷达原理与应用[M]. 北京:电子工业出版社, 2010: 44-45.
[14]TOPP G C, DAVIS J L, ANNAN A P. Electromagnetic Determination of Soil Water Content: Measurements in Coaxial Transmission Lines[J]. Water Resources Research, 1980, 16(3): 574-582.
[15]LAURENS S, BALAYSSAC J P, RHAZI J, et al. Non-destructive Evaluation of Concrete Moisture by GPR: Experimental Study and Direct Modeling[J]. Materials and Structures, 2005, 38(9): 827-832.
[16]DOBSON M C, ULABY F T, HALLIKAINEN M T, et al. Microwave Dielectric Behaviour of Wet Soil Part II: Dielectric Mixing Models[J]. IEEE Transactions on Geoscience and Remote Sensing, 1985, GE-23(1): 35-46.
基金
中国博士后自然科学基金项目(2017M613175);国家自然科学基金项目(11572246);国家重点实验室培育基地基金项目(2016ZZKT-8);陕西省自然科学基金青年项目(2018JQ5203)
PDF(5164 KB)
