Distributed optical fibre sensing for early detection of shallow landslides triggering

Area of Science:

• Geotechnical Engineering
• Geophysics
• Sensing Technology

Background:

• Landslides pose significant risks, necessitating improved monitoring and early warning systems.
• Traditional sensors have limitations in capturing the complex dynamics of slope failure.
• Optical fiber sensing offers a novel approach for high-resolution strain measurement.

Purpose of the Study:

• To investigate the efficacy of distributed optical fiber sensing in measuring landslide-induced strains.
• To compare optical fiber sensing data with traditional geotechnical sensors.
• To analyze the strain evolution during slope failure for enhanced landslide dynamics understanding.

Main Methods:

• A large-scale physical slope model was instrumented with a buried optical fiber cable along the anticipated failure surface.
• Optical frequency domain reflectometry (OFDR) was employed to interrogate the fiber optic sensor.
• Strain evolution was measured with centimeter spatial resolution.
• Soil moisture and pore water pressure sensors were installed for comparative analysis.

Main Results:

• The optical fiber sensing system successfully measured strain evolution with high spatial resolution until slope failure.
• Distinct phases of landslide development were identified through strain field analysis.
• Precursory signs of failure were detected by the optical fiber sensor well in advance of the collapse.
• Optical fiber data provided unprecedented insight into landslide dynamics.

Conclusions:

• Distributed optical fiber sensing is a viable and effective tool for monitoring landslide-induced strains.
• This technology offers superior resolution and insight compared to traditional methods.
• Optical fiber sensing holds significant potential for developing more effective landslide early warning systems.