Optical Fiber Technology to Monitor Slope Movement

Abstract

Recently, awareness about hazards caused by landslides and the importance given to the concept of risk management has been continuously increasing. As a consequence, early warning systems have gained much more importance in terms of risk management. Different instrumentation techniques such as inclinometers, tilt meters, extensometers and ground based LIDAR systems have been used to monitor landslides and/or slopes. All these techniques have their own advantages and disadvantages, but the optical fiber system has certain superiority over these methods. Fiber optic based technology serves an incessant process to acquire the data during the monitoring operation, a significant need for such operations and early warning systems. The main objective of this study is to monitor slope movement regardless of lithology and failure types. Equipment utilized in an attempt to accomplish this scope has consisted of a laboratory experimental set-up and an optical fiber system containing Optical Time Domain Reflectometer (OTDR), optical fiber cables and heterocore sensors. A laboratory set-up was constructed to simulate landslide phenomenon and to record movement. The laboratory experiment set-up contains two identical trays filled with soil that posesses an inclination mechanism to represent ideal landslide conditions. The tests show that fiber optical technology can be utilized as a landslide monitoring tool and is useful in determining mass movement throughout a fiber array. These studies are expected to lead risk assessment studies in hazard prone regions and also at the construction and post-construction period of all other displacement dependent engineering projects such as open road cuts.