介绍了地质雷达检测桥面层厚度的原理, 应用美国GSSI公司生产的Handy scan手持地质雷达对京珠高速公路某段的三座大桥进行了无损检测, 对实测采集到的地质雷达信号应用专业处理软件Radan进行数字信号处理, 处理的内容包括压制随机的和规则的干扰, 滤频及以最大分辨率显示实测图像, 获得了桥面各层厚度变化的连续清晰图像, 提取反射波参数计算了桥跨多点的各层检测厚度, 得到每跨各层的检测平均厚度, 同时进行了钻孔取芯检测, 应用研究发现, 采用中心频率为1 GHz的地质雷达在混凝土结构中可探测的深度为20 cm左右, 属浅层地质雷达, 可测得桥面结构前三层的厚度, 应用效果较好; 对于第四层结构, 由于其距离表面较深, 雷达波的衰减较为明显, 检测效果不明显, 可采用更低中心频率的地质雷达进行进一步的检测工作。地质雷达对于前三层结构厚度的检测结果是可信的, 可作为工程质量评价的依据。

Principle of deck thickness radar detecting was introduced. Non-destructive test of three bridges in the Beijing-Zhuhai expressway was carried out by use of Handy scan ground penetrating radar produced by GSSI company of the United States. Radar signal processing software Radan was used for digital signal processing to the detected radar image, including suppression of random and regular interference, filtering frequency, improving the resolution. The processed continuous and clear image showed that the deck thickness changed along the test line. Useful parameters in the reflected wave were extracted for the layers thickness calculation of multi-point of each span. Average thickness of three layers of each span was calculated. The application research showed that the ground penetrating radar with center frequency of 1 GHz could detect the depth about 20cm in concrete structures, which was shallow detecting ground penetrating radar. It can detect three layers of the bridge deck. The test result was not obvious for the fourth layer because of its long distance from the surface. Radars with lower center frequency are recommended to detect the fourth layer of the bridge deck. The test result of thickness of bridge deck by the ground penetrating radar is reliable and can be the basis for evaluation of the project quality.