长江科学院院报 ›› 2018, Vol. 35 ›› Issue (3): 110-115.DOI: 10.11988/ckyyb.20171083

• 岩土工程测试与监测 • 上一篇    下一篇

基于地质雷达法的非饱和黄土介电特性及界面反射机理研究

吕高a,b, 杨杰a,b, 李宁a, 胡德秀a,b   

  1. 西安理工大学 a.水利水电学院; b.省部共建西北旱区生态水利国家重点实验室,西安 710048
  • 收稿日期:2017-09-19 出版日期:2018-03-01 发布日期:2018-03-16
  • 作者简介:吕 高(1986-),男,陕西西安人,博士后,主要从事地质雷达探测、岩土工程数值模拟等方面的研究工作。E-mail:lvgao116@xaut.edu.cn
  • 基金资助:
    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)

Research on Dielectric Property and Interface Reflection Mechanism of Unsaturated Loess by Ground Penetrating Radar

LÜ Gao1,2, YANG Jie1,2, LI Ning1, HU De-xiu1,2   

  1. 1. Institute of Water Resources and Hydro-electric Engineering, Xi’an University of Technology,Xi’an 710048,China;
    2.State Key Laboratory of Eco-hydraulics in Northwest Arid Region of China, Xi’an University of Technology, Xi’an 710048,China
  • Received:2017-09-19 Published:2018-03-01 Online:2018-03-16

摘要: 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。

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

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.

Key words: unsaturated loess, ground penetrating radar, relative permittivity, moisture content, finite-different time-domain forward, interface reflection

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