水泥路面脱空区域GPR信号的时频域分析

Time-frequency Domain Analysis of GPR Signal in Cement Void Area

水泥路面脱空是导致路面板块断裂的主要因素,若能及早确定脱空区域的范围,则可为水泥路面结构安全性的力学分析提供依据。以水泥路面脱空病害为研究对象,采用正演模拟方法研究了不同脱空形状以及不同填充物质对GPR(探地雷达)响应信号的影响;采用编程软件设计了探地雷达(GPR)信号处理模块,使用连续小波变换(CWT)提取脱空区域的信号特征,对病害区域进行了3D重构;并将上述方法在构建的室内脱空模型上进行了验证。结果表明,设计的后处理软件可实现GPR信号的后处理功能,为正演和反演数据的信号分析提供有效工具;经过CWT处理后的脱空与正常路面的GPR信号在时频域差异明显,CWT图谱能量集中区域可表征脱空的深度和范围,CWT结果还可用于3D可视化分析,为解译脱空区域范围以及判断是否含水提供参考,这为GPR信号解译提供了新的处理手段。

Void is the main factor leading to the fracture of cement slab,the early location of void area can provide a basis for the slab structural safety analysis.Void area in the cement pavement was taken as the target,and its influence factors,including void shape and filling medium,were considered and analyzed with FDTD method.CWT(continuous wavelet transforms)method was adopted to process the GPR signal.To obtain the original parameters of GPR signal,a GPR signal processing module was designed.Our proposed void feature extraction method was tested both in simulated and lab model.The results indicate that the designed software can realize the post-processing function of GPR signal,the normal and void area have significant difference in time-frequency domain after CWT process.The energy concentration area of CWT map can represent the depth and range of void area,which could be also viewed in the CWT 3D image and used to determine the void area whether contain water or not.Our method provides a foundation for GPR signal processing.