Introduction to an FBG-based inclinometer and its application to landslide monitoring

Abstract

This paper presents a self-designed in-place inclinometer based on fiber Bragg grating (FBG) technology and introduces its application to a landslide monitoring project in Wenzhou, China. The working principle of the FBG-based inclinometer is briefly introduced. The FBG-based inclinometers were installed into nine boreholes that were distributed over different areas of the landslide. After 4 months of monitoring, the deformation of the soil mass at different depths above the bedrock within the landslide was captured by the inclinometers. The results indicated that the soil deformation above the bedrock was relatively large whereas that below the bedrock was minor. Based on the field monitoring data, the potential sliding zones were predicted to be the areas near the bedrock. In addition, a limit equilibrium analysis was carried out to evaluate the stability of the landslide under the circumstance of rainfall. The analyses showed that the calculated failure surface was consistent with the field observations, indicating that the monitoring data recorded by FBGs were accurate. These findings demonstrate that a combination of FBG technique and limit equilibrium analysis can be used to evaluate the stability of landslides effectively.