混凝土构件深浅埋钢筋模拟检测试验与偏移分析

应用地质雷达进行混凝土构件缺陷检测时,浅埋钢筋会对层下钢筋及目标物的探测造成干扰,对其原因进行分析并采取有效的手段去除干扰具有重要意义。通过理论计算设计了检测试验方案,在沙槽中埋设不同埋深钢筋模拟混凝土中钢筋的检测,运用多种偏移手段对检测信号进行处理。结果表明:浅层钢筋对深层钢筋检测的干扰,与地质雷达探测区域覆盖的浅层钢筋的长度有关;相较于绕射叠加偏移、Kirchoff偏移、F-K域偏移等方法,Tau-p域偏移能够更好地对钢筋检测信号进行偏移处理,钢筋的位置被更为准确地识别,偏移后的地质雷达三维图像变得平坦、干净。结合工程实例,对地质雷达数据进行了偏移分析,取得了良好的效果。

Simulation test and migration analysis for detection signal of deep and shallow reinforcement in concrete member

The detections of reinforcement and target are affected by shallow buried reinforcement in concrete member with ground penetrating radar(GPR)testing defects. It is of great importance to study the cause and elimination of the interference. Based on the theoretical calculation, the numerical experimentations were designed, and the reinforcement detection was simulated by embedding reinforcement of different depths in the sand tank. Moreover, the signal was processed by various migration methods. The results show that the interference is relevant with the length of shallow reinforcement within GPR detection area. By comparing with diffraction stack, Kirchoff and F-K migration methods, Tau-p domain migration can deal with the reinforcement detection signal better. The position of reinforcement is more accurately identified. The 3D image of GPR become flat and clean through Tau-p domain migration. Finally,the GPR data in a practical project was well analyzed by Tau-p migration.