(1. 中南大學(xué) 地球科學(xué)與信息物理學(xué)院，長(zhǎng)沙 410083；
2. 華東有色地質(zhì)勘查局，南京 210007；
3. 廣東省有色金屬地質(zhì)勘查局 地質(zhì)工程中心，廣州 510080)
摘 要: 基于Maxwell方程組，得到滿足Debye關(guān)系的頻散介質(zhì)探地雷達(dá)有限元波動(dòng)方程，推導(dǎo)有限單元法的離散格式，并編制正演模擬MATLAB程序。選取一典型地電模型，分別對(duì)考慮頻散與不考慮頻散，頻散介質(zhì)中同一模型不同頻率天線的雷達(dá)探測(cè)結(jié)果進(jìn)行分析。結(jié)果表明：雷達(dá)波在頻散介質(zhì)中傳播時(shí)，具有波形嚴(yán)重畸變、能量迅速衰減的特性，如果不考慮介質(zhì)對(duì)波吸收衰減的探地雷達(dá)正演，其結(jié)果與實(shí)測(cè)的雷達(dá)波形存在較大的偏差。并把該結(jié)論應(yīng)用到廣東省某高速公路的圓管涵實(shí)際資料解釋中，有效地解答了實(shí)測(cè)資料解釋中遇到的問(wèn)題，并對(duì)GPR工程實(shí)測(cè)過(guò)程中天線頻率的選取提出了有益建議。
關(guān)鍵字: 探地雷達(dá)；頻散介質(zhì)；有限單元法；正演；高速公路；圓管涵
（1. School of Geosciences and Info-Physics, Central South University, Changsha 410083, China;
2. East China Mineral Exploration and Development Bureau, Nanjing 210007, China;
3. Center of Geological and Engineering, Geology Bureau for Nonferrous Metals of Guangdong Province,
Guangzhou 510080, China）
Abstract:Based on the Maxwell equations, we obtained the GPR wave equation satisfying the Debye relationship in dispersive media, deduced the finite element discretization format of this equation, and made a GPR forward simulation program by MATLAB. Choosing a typical geoelectric model, we analyzed the dispersive media GPR results in different frequencies while we considered dispersion and no dispersion, separately. The results show that the characteristics and rules of GPR waveform wave propagation process often produce distortion and attenuation in dispersive medium, and there is a discrepancy between the GPR forward modeling results without considering the attenuation of the medium and the measured radar waveform. We applied these conclusions to interpret the actual data of pipe culvert in a highway of Guangdong Province, China, which explained the measured data effectively, and made a good suggestion to select the antenna frequency in GPR measurement process.
Key words: ground penetrating radar; dispersive medium; finite element method; forward simulation; highway; circular culvert
