Journal of the Korean Society of Mineral and Energy Resources Engineers ISSN:2288-0291(Print) 2288-2790(Online) 한국자원공학회지

In this study, we used 3-D Kirchhoff prestack depth migration of Ground Penetrating Radar(GPR) data to image the inside of the stone pagoda as a tool of Non-Destructive Test(NDT) for inspection of the structural safety of a stone pagoda. For a simple model of one outer stone and one inner stone with a thin air layer, we found that the result of 3-D migration of a stone pagoda has better resolution than that of subsurface because of the higher ray path coverage and that the result showed well the air layers, which are important objects in analysis of structural safety. For a model with three different sized inner stones, a high resolution image was obtained. Therefore, we confirmed that 3-D Kirchhoff prestack depth migration is an effective scheme for the inspection of structural safety of stone pagodas. In addition 3-D Kirchhoff migration was applied to field data of two stone pagodas; Chungung-dong five-story stone pagoda and Jeongnimsaji five-story stone pagoda. From the migrated inner images of each stone pagoda, it was confirmed that the foundation of the former pagoda consisted of many inner rocks, whereas that of the latter one was relatively well preserved despite of its long history.