衬砌脱空雷达波数值模拟与定量解释

地质雷达是隧道衬砌脱空病害检测主要方法,常规探测理论是以菲涅尔带半径为最终空间分辨率,小于该半径的脱空不能识别,而大于该半径的脱空在定量解释上也存在困难。针对隧道脱空检测常用900 MHz天线,采用时域有限差分对不同脱空量的模型进行雷达波数字模拟计算,并合成雷达记录剖面。在分析脱空区域顶、底反射叠加波形特征及振幅变化的基础上,给出不同脱空量模型的波形双峰极值点幅度变化规律,提出基于极值点振幅比反演脱空量的解释策略,并给出反演结果的拟合算法。该策略不仅为脱空区脱空量分析提供一条途经,同时为地质雷达在脱空定量解释方面提供有效的技术手段。

Simulation of Lining Void Area by Radar Waves and Explanatory Strategy

Application of the ground pentrating radar is the dominant method in detecting the tunnel lining void disease.By conventional analysis,the Fresnel Zone Radius is the limited spatial resolution for detected objects.When the void is smaller than the Radius,the void can not be identified;when the void is bigger than the Radius,quantitative analysis is difficult.By the finite difference time domain,the radar time sections of different void models are constructed with the usually used 900 MHz antenna.On the basis of analyzing the variety of characteristics and swings of waves,the law of varying double peak values between the top and bottom of the void is gaven.The explanatory strategy and arithmetic of quantitative interpretation are brought forward,that provides the new technique and good means to detect voids by GPR data.