Integration of Polymer Optical Fibers in Nonwoven Geotextiles for Continuous Strain Monitoring

Geotextiles are often used in large scale civil engineering projects, such as dams and embankments. Failure of these structures can lead to significant economic losses as well as mortal danger. Still, current monitoring solutions of such structures often rely on discontinuous, external systems and procedures, which are labor intensive and cannot be used at short notice in extreme load cases. Since geotextiles support large parts of the structures, the integration of a continuously operating sensor system in the geotextiles is an obvious solution. One such sensor system is based on polymer optical fibers (POF), which are used in various applications as strain sensors. In this paper, various methods are investigated to integrate polymer optical fibers into nonwoven geotextiles. The methods are examined for their suitability and behavior under load. The results show that adhesive and heat-based methods are most suitable to connect POF and nonwoven geotextiles, while a Velcro tape does not provide sufficient connection. For all methods, maximum strain is limited to values < 5% elongation.