Study On Ground Penetrating Radar For Monitoring The Integrity Of Piles Composite Foundation

Composite foundation is widely used as a kind of concealed works in civil engineering construction in our country. But there is a lack of economic and effective technical means to monitor the quality of the piles in composite foundation.Ground penetrating radar (GPR) is a geophysical method that uses radar pulses to image the subsurface.With the progress of science and technology,GPR is used in Geological and hydrological exploration, Archeology,Civil engineering,Military and security etc.It is difficult to monitor the quality of the piles in composite foundation, and the method of radar is put forward. Numerical simulations of radar monitoring on flexural pile are processed. The results show that the method of radar monitoring can be used to check the quality of the piles accurately.This study involves an experiment of integrity detection of the rammed soil-cement pile based on the principle of GPR. The paper discussed its details about the choice of antenna, the best time for detection and the method of detection.The results of the length and defects of the piles in composite foundation in different periods show that it is an effective method20days after piling. Furthermore, the age of cement, the ration between soil and cement, moisture content are studied and the reasonable proposals applied for the actual project are present. The study laid the foundation for the use of GPR in detection of flexible piles in composite foundation.This study includes an experiment of integrity detection of the cement fly-ash gravel pile based on the principle of GPR.The difference of inspection images of different mix proportion of piles and the effect of moisture content were analyzed.Then this technology is applied in some highway. By comparing with the results of another company, the characteristics including high precision and speed are found. So the technology can be far and wide used.