钢筋混凝土缺陷的探地雷达检测模拟与成像效果

MODELING AND IMAGING EFFECTS OF GPR DETECTION OF REINFORCED CONCRETE DEFECTS

采用时域有限差分方法模拟钢筋混凝土缺陷体的雷达检测,并利用频率域-波数域偏移(F-K)方法进行数据处理。通过F-K偏移削弱钢筋网强干扰信号对缺陷体信号的影响,使钢筋网及缺陷体的反射电磁波信号聚焦归位,从而突出缺陷体及分布范围。研究表明,F-K偏移能很好地把将钢筋网及缺陷体的绕射波聚集归位,有效分离目标体,提高纵向分辨率能力,利于准确解释缺陷体及形态特征。

Ground Penetrating Radar （GPR） has been widely applied in civil engineering and environmental detection as a high resolution and efficient nondestructive testing （NDT） method. For example, it is used to detect the rebar concrete structures. In this paper, the FDTD method was used to simulate the GPR detection of the defects in the reinforced concrete and to migrate with the frequency wavenumber （F-K） migration method. This study shows that the technique can be used to reduce the multiple and diffraction of rebar. With the F-K migration method, the diffraction energy is efficiently focused on rebar and defects, which can not only separate the signals of rebar from those of defects but also improve range resolution. As a result, the distribution and shape of defects can be easily interpreted.