High Precision, Small Size and Flexible FBG Strain Sensor for Slope Model Monitoring

Hongbin Xu,Xinyu Zheng,Yanliang Du,Xu Sun,Feng Li,Yang Gao,Bo Liu,Weigang Zhao

doi:10.3390/s19122716

Abstract

In this paper, a soft fiber Bragg grating (FBG) strain sensor was constructed of a rubber strip, FBGs and steel plates, which exhibits the advantages of high precision and a small size. A series of FBGs was uniformly pasted on a flexible rubber strip which can monitor the slope deformation by measuring the bending deformation of the rubber strip. Most notably, this sensor can be used to monitor horizontal displacement in the subsurface of the slope model. The relationships among the bending angle of the rubber strip, the strain of the rubber strip, and the subsurface deformation of the slope model were established. In addition, the subsurface deformation of the slope model can be obtained by the FBG strain sensor monitoring. Since a rigid-flexible structure was formed by uniformly pasting a series of steel plates on the other side of the rubber strip, the sensitivity of the FBG strain sensor was improved to be 1.5425 nm/°. The measurement results verify that the FBG strain sensor shows good performance, and the model test results demonstrate that the FBG strain sensor can be used for monitoring the subsurface deformation of the slope model.

Highlights

Landslides have attracted great attention, as they are serious geological hazards that cause a significant loss of property and human lives
A model test was carried out to verify the performance of the fiber Bragg grating (FBG) strain sensor by digging the
An FBG strain sensor was developed to monitor the displacement of the slope model by measuring the strain of the bending rubber strip

Summary

Introduction

Landslides have attracted great attention, as they are serious geological hazards that cause a significant loss of property and human lives. It is important to study the slippage mechanism of the high and steep slopes and forecast the landslide [1]. The slope model test is an essential means to study the slip mechanism of the slope, and the corresponding deformation monitoring is necessary [2]. The common tilt sensor with a large size is not suitable for monitoring slope model deformation. Traditional slope model monitoring technologies include a multi-point displacement meter (MPDM) [3], non-contact remote laser Vibrometry, calipers [4], photograph measure and CCD laser displacement sensor [5]. Since the fixed end of the MPDM is difficult to be combined with soil firmly, the deformation of the slope model is unavailable to be monitored accurately

Methods

Results

Conclusion