Forward modeling and application of ground-penetrating radar for hidden defects in a shipyard floor

During the long-term service of a shipyard floor, hidden dangers such as erosion, water bubbling, and porosity easily occur underneath the shipyard floor, which affects the safe operation of the project. Ground-penetrating radar (GPR), being a fast and non-destructive detection method, can be used for detecting hidden dangers in a shipyard. An actual shipyard project was taken as a research object in this study, and the GPR forward modeling of the typical working conditions of the dock floor was performed. The modeling was based on the measurements of the electrical parameters of the media under the dock floor in different states, and the response characteristics in the time and frequency domains were analyzed. The interpretation principles of different hidden dangers of the dock floor were summarized and verified in the engineering field. Finally, the formation mechanism of the anomalous features in the time-domain mapping was examined. The results showed that the dielectric constant and conductivity of the bedding layer and soil foundation under the water-saturated state increased considerably; the difference in electrical parameters between the water-saturated and hazardous areas caused abnormal responses such as "tail dragging," multiple waves, and a low-frequency offset in the detection results. The response characteristics of the different hazards served as a basis for accurately identifying the hazard categories under the bottom plate. This study is expected to supplement the research application of GPR in detecting water-induced hazards.