大坝面板脱空地质雷达波场数值模拟与瞬时属性分析  

Numerical simulation of dam face disengaging ground penetrating radar wave field and instantaneous attribute analysis

作　　者：徐浩[1,2] 刘江平[1] 余信江 XU Hao;LIU Jiangping;YU Xinjiang(Institute of Geophysics and Geomatics,China University of Geosciences(Wuhan),Wuhan 430074,China;Changjiang River Scientific Research Institute,Wuhan 430010,China)

机构地区：[1]中国地质大学(武汉)地球物理与空间信息学院,湖北武汉430074 [2]长江科学院,湖北武汉430010

出　　处：《中南大学学报（自然科学版）》2021年第2期489-497,共9页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(51709015)。

摘　　要：针对不同类型大坝面板存在的脱空问题,依据实际面板组成结构与物性参数,采用时间域有限差分法,对无钢筋、单层与双层钢筋面板脱空模型进行雷达波场数值模拟与瞬时属性提取,分析不同脱空情况下雷达波场响应特征。研究结果表明:当面板出现脱空隐患时,脱空区域出现能量较强的反射波,脱空反射波相位与面板底部反射波相位相反,脱空反射同相轴出现明显的"下拉"现象,脱空厚度越大,脱空反射同相轴"下拉"幅度越大;当面板内部存在钢筋时,脱空反射同相轴连续性变差,随着面板内部钢筋层数增加、钢筋间距减小,脱空反射波形态与反射同相轴"下拉"现象逐渐消失;在雷达数据信噪比较低且从雷达剖面图无法识别脱空存在的情况下,需借助瞬时属性来识别脱空隐患。According to the composition structure and physical parameter of dam penal,radar wave field of different types of dam panel disengaging was taken through the finite-difference time domain,including inexistence reinforcement,single and double reinforced.Then the simulation and instantaneous attribute extracted by Hilbert Transform were analyzed.The results show reflected wave with strong energy can be recognized and the phase of the disengaging reflection wave is opposite to that of the bottom of the panel.Disengaging reflection events stretch down in the range of disengaging as long as disengaging appears under the panel.The greater thickness of the void,the greater amplitude of void reflection events stretching down.When there is reinforcement in the panel,the continuity of reflection events becomes worse.Disengaging reflected wave form and reflection events variation cannot be resolved with the increase of layers of reinforcement and the decrease of the spacing of reinforcement.Disengaging needs to be identified by means of instantaneous attribute when signal-to-noise ratio of radar data is low and disengaging cannot be recognized through radar profile.

关 键 词：地质雷达 面板脱空 时间域有限差分法 瞬时属性 反射同相轴 

分 类 号：P631[天文地球—地质矿产勘探]