Application of a new measuring method using an optical fiber strain sensor to an underground tunnel

The measuring methods using optical fiber strain sensors are being considered as structural monitoring technologies for concrete structures. B-OTDR method using optical fiber strain sensors can measure continuous strain along an optical fiber over 80km. Because of this advantage, it is expected to measure deformations in large-scale structures. But, this new measuring method, B-OTDR method, is just in development. There is very few case of applying this measuring method to actual structures. This paper describes a new measuring method using optical fiber strain sensors (B-OTDR method) applying to an actual concrete underground tunnel which was expected to deform by new shaft work near this tunnel. As a result, this method using optical fiber strain sensors can measure the deformation of the underground tunnel.