摘要
随着城市化建设步伐加快,如何快速准确地确定地下管线的埋设情况及管道材质种类成为工程地质勘探重要的研究课题.本文通过时域有限差分法(FDTD),对地质雷达探测地下管线的成像进行正演模拟,分析了介电常数影响下金属管线与非金属管线的成像特征.在此基础上,进一步分析了地层与不同介电常数管线分界处的波幅特征,研究了不同介电常数情况下管-土分界面的波幅规律.在相同埋藏条件下,把不同目标体(管道)分界点的波幅与特定材质管道(介电常数为1)分界点的波幅A1的比值定义为相对波幅.根据相对波幅大小,可以分类判别地下管线材质,对于金属管线而言,相对波幅大于1.5,而对于非金属管线,相对波幅小于1.据此,提出了地质雷达探测地下管线时对金属材料与非金属材料地下管线进行分类判别的一种方法,并通过现场试验验证了该方法的有效性.
With the accelerating pace of urbanization, how to quickly and accurately determine the buried underground pipeline layout and pipeline types has become an important research topic for engineering geological exploration. In this paper, the Finite Difference Time Domain（ FDTD） method is used to perform forward simulation of the imaging of underground pipelines detected by GPR. The imaging characteristics of metal pipelines and nonmetallic pipelines under the influence of dielectric constants are analyzed,The greater the difference between the dielectric constant of the target body and the geological background,the clearer the image is,the easier it is to be detected,and the more significant the amplitude is. On this basis,the amplitude characteristics of the interface between the stratum and the different dielectric constant pipelines are further analyzed,and the amplitude law of the tubesoil interface at different dielectric constants is studied. When the dielectric constant of the pipeline is not changed,the amplitude value at the demarcation point increases with the increase of the dielectric constant of the stratum,but the increase speed is slower;the difference between the dielectric constants of different pipeline materials is larger,and the amplitude at the demarcation point is greater. In order to classify different material pipelines according to the difference value in amplitude,when the burial conditions is same,the ratio of the wave amplitude at the boundary point of different target bodies（ pipes） to the amplitude A1 at the demarcation point of the specific material pipeline（ dielectric constant 1） is defined as relative amplitude A0. For metal pipelines,the relative amplitude is greater than 1. 5,and for nonmetallic pipelines,the relative amplitude is less than 1. Based on this,a method for classifying discriminating buried underground pipelines of metal materials and non-metallic materials during the detection of underground pipelines by geological radars is proposed.Finally,as an exampl
作者
姚显春
闫茂
吕高
李宁
YAO Xian-chun;YAN Mao;LU Gao;LI Ning(Institute of Geotechnical Engineering,Xi＇an University of Technology,Xi＇an 710048,China)
出处
《地球物理学进展》
CSCD
北大核心
2018年第4期1740-1747,共8页
Progress in Geophysics
基金
国家自然科学基金"复杂地质条件下水工隧洞围岩稳定性分析与支护结构设计理论研究"(51179153)国家自然科学基金"岩体旋切式触探机理与现场力学参数快速测试研究"(51779207)资助
