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为解决探地雷达(GPR)检测桥面隐性病害时钢筋层下方病害因被钢筋层干扰和屏蔽而无法准确检测的问题,研究了信号屏蔽机理,提出了相应的解决方法。基于雷达波传播原理,研究了钢筋层下方病害信息被屏蔽的原因,在此基础上,对比了VV和HH两种极化方式的散射特性,分析了钢筋间距和直径对天线散射特性的影响,进而研究了钢筋层下部病害的图谱特征,并用F-K偏移算法还原了病害位置。结果表明:钢筋直径和间距是影响雷达波散射特性的主要因素,直径越大,间距越小,雷达波经过后的散射宽度越大,越不利于检测钢筋下方信息;天线极化方式影响雷达波经过钢筋后的散射宽度,HH极化较VV极化对钢筋散射宽度大,适用于检测钢筋位置,而VV极化方式可有效削弱钢筋的散射强度,能检测到50mm间距的钢筋层下方的孔洞病害,F-K法可有效还原孔洞和钢筋的位置,这为辨识桥面和其他建筑物钢筋层下方的隐性病害提供了一种有效方法。
In order to solve the problem that the disease under the reinforcement layer can not be accurately detected due to the interference and shielding of the reinforcement layer when the ground penetrating radar (GPR) detects the hidden disease of the bridge deck, the signal shielding mechanism is studied and the corresponding solutions are proposed. Based on the principle of radar wave propagation, the reason why the disease information is shielded beneath the reinforcement layer was studied. Based on this, the scattering characteristics of the two polarization modes of VV and HH were contrasted. The influence of spacing and diameter of reinforcement on the scattering characteristics was analyzed. Then the characteristics of the lower part of the reinforcement layer were studied, and the location of the disease was restored by FK migration algorithm. The results show that the diameter and spacing of rebar are the main factors that affect the scattering characteristics of the radar. The larger the diameter and the smaller the spacing, the larger the scattering width after the radar passes. The less it is to detect the information under the rebar. The polarization of the antenna affects the radar wave The scattering width of the steel after reinforcement, HH polarization VV polarization of the scattering width of the steel is large, suitable for detecting the location of steel, and VV polarization mode can effectively weaken the scattering intensity of steel, can detect the hole 50mm spacing below the reinforcement layer Disease, FK method can effectively restore the location of holes and rebar, which provides an effective method for identifying the hidden diseases under the steel deck of bridge deck and other buildings.