New Technology Study Of GPR On Tunnel Quality Nondestructive Detection

There is a difficult problem how rapidly and accurately nondestructive detects the tunnel quality which is concerned by technical engineers because tunnel structural has big span and long distance features. Ground penetrating radar is a new nondestructive technology which transmitting rules is accord with Maxwell equation group and Wave equation, using ultra high short-pulse electromagnetic waves transmit and reflect in the medium can quickly get the detailed information about the survey area. GPR is the best nondestructive equipment to detect the tunnel quality with the high resolution, high efficiency and nondestructive features.This paper firstly introduced the development and principle of GPR, and then discussed its application on tunnel quality test. Focusing on the probably existed quality problems, we mainly carry on the study on the three aspects which are parameters setup and technical keys of data collection, filters setup of data process and data interpretation in laboratory and real field test ways. Finally, we can solve the following quality problems of tunnel lining quality.The thickness of lining concreteThe position of reinforcement or steel grate archThe cementing condition of lining concreteThe cavities that located between lining concrete and surrounding rockArray antenna radar uses one control unit and multi-antennas which is the same or different frequencies to collect multi-channels data at the same time. Its data collection modes generally are monostatic and bistatic, the first is well in the object which is perpendicular to the scan line, and the second is good at the target which is inclining to the scan direction. It is a development trend for radar technology because array antenna radar can greatly improve the detection precision and efficiency.Radar has obviously advantages over other steel detecting equipments to locate double layer steels. For example, single-side survey, bigger depth and higher resolution. This paper further studied the features of radar section and trace window together and improved the location precision of steels, especially for the second layer steels. Moreover, the method of detecting double layer steels also provides a reference for other field application, for instance, civil engineering and so on.