The Application Of Ground Penetrating Radar Detection Technology On Concealed Defects Of Concrete Faced Rock-fill Dam

With the emergence of more and more high Concrete Faced Rock—fill Dam(CFRD),new problems of CFRD have gradually attracted people's attention.Among them, void of CFRD is the difficulty and hotspot. Void of CFRD will lead to the CFRD appears uneven stress,increasing deformation. It can also cause cracks in the panel, affect the working performance of rock fill dam. The anti-seepage performance of pane would be reduced, thus affecting the safe operation of the dam, and even endanger the safety of the whole dam. Therefore, accurate detection and effective management of the situation of void of CFRD is partic ularly important.It is necessary to assess the condition of foundation by proper means, especially the size and ditribution of void holes under surface of dam when separation between dam and foundation occurs. The radar technology is competent to this tas k becasue of its advantages such as high precision, low condition demanding and easy operation. The purpose of this paper is to verify the ability of radar technology to detect the distribution and shape of objects by figuring out the images. By using the excellent detection performance of ground penetrating rada, personnels with rich experience in engineering practice can easily learn about the cavity in the detection of substances. However, there are still some difficulties to further calculate the contou r, volume and other details of the concealed defect. It is because the application of radar on condition assessment is still limited within the description of damage. No definite method can be able to assess the degree of degradation, let alone assessment of strengthening. Therefore the use of ground penetrating radar has very important engineering practical significance to research the volume estimate of concealed defects of Concerte Faced Rock-fill Dam.Based on the previous research on calculating the ta rget volume by geological radar, through an engineering example of using geological radar detection for rockfill dam of concealed defects, this paper makes a in-depth study of volume. By using three different frequency of radar antenna, respectively, 900 MHz, 400 MHz, 270 MHz, the author detects concrete slabs of rockfill dam, determine the distribution of panel void and select some tipical instance of concrete pavement void and detect actually again, analysis radar image, calculate the volume by simulating test data, finally, thougth inverse fitting to obtain mathematical calculation model by the result of the geological radar detection for rockfill dam(900 MH z antenna). Through the actual example verified the accuracy and applicability of mathematical calculation model. The paper provides us a method to finding concrete pavement's defects of rockfill dam or providing scientific and reliable quantitative basis. We can take some corresponding measures for processing, improve the working efficiency and quality. In a word, the method has a very important engineering practical value.