节点文献
探地雷达系统优化及在隧道地质超前预报中的应用研究
Improvement of Ground Penetrating Radar and Its Application into the Predication of Geological Conditions in Tunnel Engineering
【作者】 石刚;
【导师】 谢永利;
【作者基本信息】 长安大学 , 道路与铁道工程, 2009, 博士
【摘要】 隧道前方地质情况的预报是国内外工程地质和隧道工程界关注而又没有得到很好解决的难题,而探地雷达是近几十年发展起来的一种无损探测技术,与其它常规的探测方法相比,具有高效、快速、连续、无损、抗干扰能力强、操作方便、低成本和高分辨率成像等特点,关于探地雷达的研究一直是学术界和工程界的热点之一。本文根据雷达探测理论,从探测能力、参数设置、剖面解释技术等方面分析了探地雷达应用于公路隧道不良地质超前预报的可行性;基于电磁波在介质中的传播理论,建立了电磁波的波动方程、偶极子天线的电磁场、电磁波的时间场与空间场等,研究了雷达波在非均匀介质中传播的反射、折射、透射与散射绕射等基本规律,总结了高频电磁场下岩土介质的电磁特性以及雷达波在不同岩层中的传播与衰减规律;针对隧道内探测环境的特点,对雷达探测的数据采集和显示模式进行分析,并给出波形修正、时变增益、噪声抑制处理、直达去除等数据处理的原理和方法;开发了SIR-20型号探地雷达的数据读取接口,并针对隧道内周围环境对雷达信号的特殊干扰,把小波分解去噪和K-L变换成功地应用到探地雷达信号的后处理;基于探地雷达电磁波在介质传播中波动性质,从成像的原理和算法上进行分析,建立了克希霍夫积分法、有限差分法和频率波数域法的实时雷达剖面成像技术,并实现了实时应用。论文结合山西大运公路介休至霍州段改建工程第三合同段灵石隧道,应用探地雷达对该隧道施工过程进行全线跟踪检测。结果表明:探地雷达技术能够适应多变的地质条件,对于预报隧道前方不良地质比较可靠。
【Abstract】 Prediction of geological conditions is a highly concerned but hard to deal with problem before excavation of tunnel in engineering geology and tunnel engineering both at China and aboard. Ground penetrating radar is a newly developed nondestructive detection technique. Compared with routine detections, it is effective, fast, continuous, non-destructive, and easy for operation with good anti-interference, low cost and high resolution imaging. Ground penetrating radar has become one of the most important fields for study in engineering.Based on the radar detection theory, from its detection capability, parameters setting, and profile explanation, this paper studied the feasibility for application of ground penetrating radar into the prediction of unfavorable geological conditions in highway tunnel construction. The theoretical principle of ground penetrating radar is the propagation of electromagnetic wave through media. According to this theory, electromagnetic wave equation, electromagnetic field of dipole antenna and time field and space field of electromagnetic wave were all established. This paper also studied the reflector, refraction, transmission, scattering and diffraction of radar wave propagation through inhomogeneous media. It summarized the electromagnetic properties of electromagnetic field of high frequency through the medium of ground, and the propagation and weakening of radar wave through different terranes. For the special detection circumstance of tunnel construction, analyses at the data and display mode were performed. Date reading interface of SIR-20 ground penetrating radar was developed. As to the interference to the radar signals by surrounding of tunnel, wavelet resolution for noise suppression and K-L transforming were successfully applied in post treatment of ground penetrating radar signals. Based on electromagnetic wave properties of ground penetrating radar through media, analysis was performed on the imaging theory and arithmetic to establish kirchnoff integral method, finite-difference method and frequency-wave-number domain method. Its real time application also came true.Based on the detection with ground penetrating radar for whole Lingshi tunnel construction, which is a section of highway reconstruction from Jiexiu to Huozhou. The results show that ground penetrating radar can be used in various geological conditions. It is reliable for the unfavorable geological disaster prediction in front of tunnel face.
【Key words】 tunnel engineering; ground penetrating radar; unfavorable geological condition; wave transform; imaging;