点状不良地质体钻孔雷达响应特征的形状效应正演分析  

Borehole radar response characteristics of point unfavorable geo-bodies——Forward simulation on its geometric effect

作　　者：钟声[1,2] 王川婴[2] 吴立新[3] 吴育华 王清远[1] 

机构地区：[1]四川大学建筑与环境学院,成都610065 [2]中国科学院武汉岩土力学研究所岩土力学与工程国家重点试验室,武汉430071 [3]北京师范大学减灾与应急管理研究院,北京100875 [4]中国文化遗产研究院,北京100029

出　　处：《岩土力学》2011年第5期1583-1588,共6页Rock and Soil Mechanics

基　　金：科技部973课题(No.2011CB707102);教育部创新团队项目(No.IRT0640)

摘　　要：针对钻孔地质雷达探测工作中常见的空洞、岩溶和地下埋藏物等点状不良地质体,利用时域有限差分数值模拟方法,对岩土体内不同形状和不同埋深的目标地质体进行了雷达响应正演模型研究,并分析了这些模型的实际分辨能力和应用条件。结果表明,对于不同的探测任务,应根据感兴趣目标体的几何尺寸、分辨率要求等来选择合适的天线频率;不同几何形状的点状不良地质体所呈现的雷达剖面形式各异,且雷达反射信号强弱也不同;同一频率天线其探测分辨能力随空洞埋藏深度而变化,同一埋深下,天线频率越高,高度分辨能力效果越好。研究结果可为钻孔雷达用于岩体工程勘察、灾害隐患探测提供模拟图像认知和数据判读支持。Borehole radar can probe deep underground geoenvironment through arranging a dipole antenna in a borehole,and it is a good logging tool to obtain the electrical signals of geologic formation.According to the common point unfavorable geo-bodies in borehole radar exploration,such as cavities,karst caves and buried objects etc.,the electrical response of the tool to point unfavorable geo-bodies of different geometry and buried depth is investigated.The application conditions and resolution response capabilities of the simulation models are analyzed.It reaches that the proper antenna frequency should be chosen according to the physical dimension of object-of-interest and resolution requirement of the exploration task;and that the radar cross section of geo-bodies with different geometry appears various characteristic.The resolution capacity of borehole radar antenna varies with the buried depth of geo-bodies;and the borehole radar with higher frequency antenna can obtain reflected signals of higher resolution.However,the reflected signals detected by the borehole radar with a higher frequency will attenuate faster than one with lower frequency antenna.The results provide visualized perceptual knowledge and abundant interpretation support for borehole radar using in geologic survey and potential disaster detection,and help to improve the accuracy of geological interpretation.

关 键 词：钻孔地质雷达 FDTD 形状效应 点状不良地质体 

分 类 号：TN95[电子电信—信号与信息处理] P58[电子电信—信息与通信工程]