Arslan, Arzu (Middle East Technical Univ.) | Akgün, Haluk (Middle East Technical Univ.) | Koçkar, Mustafa Kerem (Gazi Univ.) | Eker, Arif Mert (SDS Energy Inc) | Kelam, Mehmet Abdullah (GEOLAB Geotechnics Const. Inc.)
Recently, early warning systems have gained much more importance in terms of risk management since awareness regarding landslide hazards has increased dramatically. Different instrumentation techniques have used to monitor mass movements. Although all techniques have their own advantages and disadvantages, optical fiber system has certain superiority over others with an incessant data acquisition capability. The main objective of this study is to monitor slope movement regardless of lithology and failure types. Equipment utilized consists of an optical fiber system containing Brillouin Optical Time Domain Reflectometer (BOTDR) and optical fiber cables. The tests show that fiber optical technology could be used as a monitoring tool and is useful in determining slope movement throughout a fiber array. The results of this study are expected to be used in risk assessment studies in hazard prone regions and during the construction and post construction period.
Landslide is one of the most destructive natural hazards in Turkey and around the world (Gökçe et al. 2008). Significance of mass movement studies becomes obvious when the number of landslide occurrences and adversely affected structures are considered. Awareness about these phenomena and the importance given to the concept of risk management has been continuously increasing due to low reoccurrence period of this disaster in a region. Therefore, early warning systems have gained popularity (i.e., Li et al. 2012, Liu et al. 2010, Pei et al. 2011). According to previous studies, geomorphological parameters, precipitation, groundwater fluctuation, seismicity, daily temperature difference, snowmelt, distribution of geological formations are the main causes of landslides and slope failures. In addition, instability of the slopes formed by the disturbance of the natural stability of the slope via manmade activities increases the level of hazard. There are many techniques use different instrumentation such as inclinometers, tiltmeters, extensometers, and ground based LIDAR to monitor landslides triggered by various effects (Savvaidis 2003 and Pei et al. 2011). Although all of these monitoring techniques have their own advantages and disadvantages, optical fiber technology became prominent owing to the characteristics of easy data transfer capability, high transmission speed, lightweight, resistance to environmental impacts and electromagnetism; and, simultaneous monitoring capability (Wang et al. 2008). Especially, capability of incessant data acquisition needed for early warning systems is a significant property. Superiority of optical fibers on these subjects makes their use reasonable for landslide monitoring as well as any displacement related engineering structure like dams, road cuts, mines and buildings.