2018 年 14 巻 1 号 p. 9-10
We have developed a new technology for surveying natural ground ahead of a tunnel face. The technique, called “DRi-Scope,” visualizes the state of ground forward of a tunnel face using an industrial endoscope. The natural ground at the point of a bit is observed directly by inserting an industrial endoscope in the water supply conduit of a rod on a hydraulic drill jumbo. Accurate geological information is obtained while minimizing the impact on the tunneling process. This paper provides an outline of the technology and describes its features. It then introduces application examples for visualization of natural ground ahead of tunnel faces.