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.

FBG-Based Monitoring of Geohazards: Current Status and Trends

“…The integral method was utilized to calculate the displacements in different depths based on linear interpolation of strain distribution along the PVC casing. Wang et al successfully installed this inclinometer in nine boreholes for landslide monitoring in Wenzhou, China [50]. The slip surface determined by the monitoring results fit well with that calculated by limit equilibrium method.…”

“…However, long-term use of inclinometers is impractical due to the disadvantages of low accuracy, poor durability, complex operation, and high costs. In recent years, several studies of in-place slope displacement monitoring using FBG-based techniques have been reported [15,16,47,48,49,50]. Figure 4 shows the typical structures of FBG in-place inclinometers.…”

Fiber optic sensing technologies potentially applicable for hypersonic wind tunnel harsh environments

“…Since the early 1990s, FBG sensing technology has been developed in several universities in China, such as Tsinghua University, Chongqing University, Wuhan University of Technology, Harbin Institute of Technology, Tianjin University, Chinese Academy of Sciences and so on. FBG sensors have been applied in many fields, like bridge health monitoring, high temperature and high pressure sensing in oil well and seismic detection [31][32][33][34]. Besides, Liu etc.…”

A Laboratory Experimental Study: An FBG-PVC Tube Integrated Device for Monitoring the Slip Surface of Landslides

“…Slope instability is considered to be closely related to slope deformation [ 22 ]. Accordingly, FBG-based inclinometers were designed to measure internal displacement and locate the slip surface by analyzing displacement data [ 23 , 24 ]. However, the detectable displacement is the result of strain accumulation within the soil mass.…”