GPR在FAST馈源支撑塔地基探测中的应用

国家重大科学项目500m大射电望远镜(简称FAST)选址贵州平塘,台址地质构造复杂,工程地质条件较差,根据FAST结构的要求,其建在直径为600m圆周上的六个馈源支撑塔基为主要承重部位,为有效地评价塔基的稳定性,治理工程地质病害,本文以地质雷达在FAST馈源支撑塔地基探测为实例,分析了地质雷达技术在这种地形条件较差的环境中应用的可行性,在探测结果与开挖验证的精度对比分析中,总结得出在工程范围较大时,应分区进行现场物性试验,得到更精确的介质相对介电常数,从而提高探测解释的精度,说明了物探技术在岩溶地基探测中发挥的重要作用。随着物探方法研究的不断深入和雷达天线及信号处理技术的迅速发展,GPR技术将能更广泛地服务于工程建设领域,特别是国家重大项目。

Application of GPR in detecting the foundation of the FAST feed supporting tower

The Five-hundred-meter Aperture Spherical Telescope （FAST）, which is a major national scientific project, is sited in Pingtang county of Guizhou province. The geologic structure of thisolocation is complex and the engineering geological condition is very poor. According to the construction plan of the FAST, six feed supporting towers will be built in a circumference of 600 meters in diameter, to function as the main load-bearing spots. As a successful example to the application of GPR in detecting the FAST feed supporting tower foundation, the feasibility of the application of GPR technique in the poor topographic conditions is analyzed. In the comparative analysis on the accuracy of the detection results and the verification of excavating, it is shown that the in-situ physical tests with different sections in a large engineering field should be carried out in order to obtain the more precise dielectric constants, which is proved to be crucial for improving the detection precision. It is also shown that the geophysical exploration technique plays an important role in karst foundation detection. With the progress on the physical detecting methods and the development on the radar antennas and signal processing techniques, it is expected that the GPR system will be more broadly applied to various fields in engineering construction, particularly in the major national projects.