Testing on depth profile of seawall by using the method of ground penetrating radar

Abstract

Testing on the depth profile of dam is an important content in the seawall project of riprap and inning. The ground penetrating radar methods can be used to get effective parameters of the profile. The structure of seawall project includes two parts, namely the primary seawall and the suppression layer of both sides. And being in the field of tide, the suppression layers are soaked by seawater everyday. So the different types of antennas must be selected to collect data of GPR during testing in the primary seawall and the suppression layer. The high-frequency antenna with 50 MHz of the drag type can collect efficiently the data of GPR during testing in the suppression layer. In the detection of the seawall project in Zhejiang, the wave groups in the migration profile of GPR wave through data procession have good continuity and are easy to trace and contrast. According to the actual thickness of riprap through testing in the obligating bore of seawall, the velocity of radar wave can be revised correctly. Then the riprap thicknesses of different points and its filling characteristics in the profile can be judged exactly. Here the effective exploration depth can reach 20 to 30 m. At the same time the section of seismic imaging methods are used to finish comparative analysis. The synthetic results are acquired, and it can offer the reliable technical parameters for the calculation of riprap stone quantity and the future construction of the inning project.