Applications of distributed fiber optic sensing technologies in geotechnical engineering monitoring

The distributed or quasi-distributed fiber optic sensing techniques such as BOTDR (Brilliouin Optical Time Domain Reflectometer), FBG (Fiber Bragg Grating), long gauges like SOFO and ROTDR (Raman optical time-domain reflectometry), which were recently developed innovative measure techniques, are introduced and compared in their principles, characteristics and applicability. This paper mainly focused on the feasibility researches of BOTDR applied into the geotechnical engineering monitoring and health diagnosis through authors' research achievements and application cases such as tunnel, land slope, foundation pit and permafrost roadbed. The major technical and economical issues in their applications are discussed, and the future key topics are presented. The research results demonstrated that the distributed or quasi-distributed fiber optic sensing techniques as the powerful monitoring tools have a very bright application perspective and strong potential market in China.