[H-TT20] New Developments in Shallow Geophysics

[HTT20-01] Cavity Fracture Detection Using Ground Penetrating Radar with Repair Contrast Agent and Automatic Infrastructure Inspection Using Autonomous Robots

*Jun Sonoda¹ (1.National Institute of Technology, Sendai College)

Keywords:ground penetrating radar, repair contrast agent, autonomous robots, social infrastructure, crack and cavity

The ground penetrating radar (GPR) is a technology for nondestructively estimating the interior of the ground from the reflected waves of radio waves in the frequency band of several hundred MHz to several GHz injected into the ground, and is effective in inspecting social infrastructures such as road cavities and concrete cracks, which have become a big problem in recent years. In particular, cavities and cracks in social infrastructures such as roads and river embankments can lead to severe accidents, so early detection and reliable repair are required. In detecting cavities and cracks by the GPR, the more significant the relative permittivity difference between the ground and the surrounding soil or concrete, the stronger the reflected wave and the easier it is to detect. We propose a new method for detecting and repairing cavities and cracks in the ground. We are developing a repair contrast agent for the GPR that can be used to detect and repair anomalies. In this study, the electrical characteristics of existing repair agents are clarified by measurement. The GPR images before and after filling the repair agent are obtained by model experiments using concrete blocks and filling experiments at the top of an existing embankment. In addition, the GPR image characteristics of the repair agent filling are clarified by a theoretical study using FDTD simulation. In addition, as a method to automate such internal inspections of roads and river embankments, we have developed an autonomous GPR using satellite positioning and LiDAR, and have applied it to actual river embankment inspections.