Reflection characteristics and morphological recognition of underground cavity diseases based on 3D ground penetrating radar

Aiming at the lack of research on 3D ground penetrating radar (GPR) in the field of cavity disease reflection characteristics, gprMax forward simulation software was adopted to establish a road structure cavity model containing various morphological features (sphere, cube, triangular prism, and irregular geometric body). Based on the mechanism analysis and rule summary of reflection characteristics of B-Scan profile image and C-Scan depth slice image, the corresponding identification method was proposed, and the engineering application and excavation verification were carried out by taking a city road in Nanchang City as an example. Analysis results show that in the two-dimensional profile image, the cavity diseases show the characteristics of a semi-hyperbola, and the position relationship between the cavity diseases and the survey line will affect the display depth of the semi-hyperbola. C-Scan depth slice images are more helpful to show the appearance of cavity diseases, especially the circular cavity diseases. In the C-Scan depth slice image, the shape of cavity diseases will gradually become larger as the time depth intensifies. Is difficult to accurately identify the morphology of cavity diseases from B-Scan profile images only, and it is necessary to combine C-Scan depth slice images for comprehensive interpretation. The proposed method helps to improve the accuracy of 3D GPR image interpretation and achieve the goal of urban road disease control and collapse prevention.