Seite - 676 - in Book of Full Papers - Symposium Hydro Engineering

COMMISSION INTERNATIONALE DES GRANDS BARRAGES ------- VINGT-SIXIÈME CONGRÈS DES GRANDS BARRAGES Autriche, juillet 2018 ------- PERMANENT SAFETY ASSESSMENT OF DAMS, LEVEES, RESERVOIRS, WATERWAYS WITH FIBER OPTIC DISTRIBUTED SENSING Régis BLIN, Daniele INAUDI SMARTEC SA SWITZERLAND 1. EARLY DETECTION AS A KEY FOR SAFETY MANAGEMENT The growing demand of safety awareness, cost effective operations and effective maintenance has rapidly stimulated, in the last decade, the development of smart monitoring techniques capable of detecting early-stage events, thus preventing structures from major failures and leading to a better knowledge of the structure itself. In this publication, the aim is to concentrate on long-term, large- scale field applications on dams, dikes and levees, based on the presented distributed technology and sensors. 2. FIBER OPTIC DISTRIBUTING SENSING 2.1. TECHNOLOGY The most developed technologies of distributed fiber optic sensors are based on Raman and Brillouin scattering. Both systems make use of a non-linear interaction between the light and the silica material of which a standard optical fiber is made. If light at a known wavelength is launched into a fiber, a very small amount of it is scattered back at every point along the fiber. The scattered light 676