Application of the optical sensing technology to the civil Engineering field with optical fiber strain measurement device (BOTDR).

Nippon Telegraph and Telephone Corporation (NTT) has developed a device (BOTDR) for measuring the strain occurring in optical fibers as a means of monitoring the condition of optical fiber telecommunications cables. The authors are promoting development of a system that uses this device to measure and monitor structural and ground deformation. This paper first introduces the measurement principle of the strain measurement method using optical fibers (BOTDR method). It then presents case studies of application to the deformation of telecommunications tunnels, ground subject to landslides and so on, and also an outline of an automatic measuring system.