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

Area of Science:

• Geotechnical Engineering
• Sensor Technology
• Materials Science

Background:

• Slope stability monitoring is crucial for preventing disasters.
• Traditional sensors may lack precision or flexibility for subsurface deformation.
• Fiber Bragg Grating (FBG) sensors offer high sensitivity and small size.

Purpose of the Study:

• To develop and validate a soft FBG strain sensor for monitoring slope subsurface deformation.
• To enhance the sensitivity of FBG sensors for improved measurement accuracy.
• To establish relationships between sensor measurements and slope model deformation.

Main Methods:

• Constructed a soft FBG sensor using a rubber strip, FBGs, and steel plates.
• Pasted FBGs uniformly on a flexible rubber strip to measure bending deformation.
• Incorporated a rigid-flexible structure with steel plates to improve sensor sensitivity.
• Established correlations between rubber strip bending angle, strain, and slope subsurface deformation.

Main Results:

• The developed FBG strain sensor demonstrated high precision and a small size.
• The sensor effectively monitored slope deformation by measuring the bending of the rubber strip.
• The rigid-flexible structure improved the FBG strain sensor's sensitivity to 1.5425 nm/°.
• Model tests confirmed the sensor's capability for monitoring subsurface deformation in slopes.

Conclusions:

• The soft FBG strain sensor is a viable tool for precise subsurface slope deformation monitoring.
• The sensor's design, incorporating a rigid-flexible structure, significantly enhances measurement sensitivity.
• The established relationships allow for accurate determination of subsurface deformation from FBG strain data.