Obayashi Corporation recently developed a new technology called "T-Photo Monitor Tunnel" that uses photogrammetry to measure and evaluate tunnel clearance deformation, and has put it into use on the Ueno Tunnel Phase 2 project on the Tokai-Hokuriku Expressway, confirming its effectiveness.
When a new tunnel is built adjacent to an existing operating tunnel, the existing tunnel may deform due to excavation work, so the tunnel clearance deformation state needs to be monitored. The "T-Photo Monitor Tunnel" monitoring technology developed by Obayashi can quickly (results judged about 30 minutes after displacement measurement) and highly accurately (resolution 0.1 mm) evaluate tunnel clearance deformation by photographing carbon fiber resin targets fixed at arbitrary positions on the tunnel wall and processing the images. In addition, only cameras need to be installed inside the tunnel, while photographing and image processing operations can be controlled from an external computer, causing no impact on passing vehicles. Furthermore, for targets soiled by dust, etc., the deformed target images after photographing can be corrected to approximate their initial shape, ensuring measurement accuracy.