影响地质雷达工作的因素分析  

Analysis of factors affecting ground-penetrating radar

作　　者：董延朋[1] 孔祥春[2] 

机构地区：[1]山东省水利科学研究院,山东济南250013 [2]北京鑫衡运科贸有限责任公司

出　　处：《物探装备》2007年第2期130-133,155,共5页Equipment for Geophysical Prospecting

摘　　要：广泛用于工程勘查、水文调查、考古探测领域的地质雷达技术日趋成熟。针对不同的勘察目标、不同的地下介质,科学地设计其探测深度和分辨率是技术应用的关键。为此,必须分析、掌握雷达工作的三个重要参数:环境电导率、介电常数和探测频率。环境电导率σ是表征介质导电能力的参数,它决定了电磁波在介质中的穿透深度,其穿透深度随电导率的增加而减小,并与土壤中的含水量有密切的关系;当σ<10-7S/m,并满足介电极限条件时,电磁波衰减小,最适宜发挥地质雷达应用效果。介电常数是影响应用效果的另一个重要因素,高频电磁波在介质中的传播速度主要取决于介质的相对介电常数,而反射信号的强弱取决于介电常数的差异。探测频率不但是制约探测深度的一个关键因素,同时也决定了探测的分辨率;探测频率越高,探测深度越浅,探测的垂直分辨率和水平分辨率越高。Ground-penetrating radar(GPR) technique widely used for engineering,hydrologic and archaeological surveys is ripe day by day.The key of technical application is to scientifically design the survey depth and resolution according to different surveyed targets and underground medium.For that reason,it should analyze and handle three important parameters of radar work:environmental conductivity,dielectric constant and surveying frequency.Environmental conductivity σ is the parameter representing the conducting ability of medium,which determines the penetrating depth of electromagnetic wave in medium that decreases with conductivity increasing and has close relationship with moisture content of soil;when it is less than 10-7S/m and meets the extreme dielectric condition,the attenuation of electromagnetic wave is reduced,which is suitable to display the GPR application effects.The dielectric constant is other important factor affecting the application effects.The propagation velocity of high-frequency electromagnetic wave mainly depends of the relative dielectric constant of medium and amplitude of reflection signals depends upon the difference of dielectric constants.The surveying frequency not only is key factor restraining the surveying depth,but also determines the surveying resolution;the higher the surveying frequency,the shallower the detective depth and the higher the detective vertical and horizontal resolutions.

关 键 词：地质雷达 环境电导率 介电常数 探测频率 

分 类 号：P627[天文地球—地质矿产勘探]