Subsurface Multi-Physical Monitoring of a Reservoir Landslide With the Fiber-Optic Nerve System

Reservoir landslides are typical geohazards with sophisticated thermo-hydro-mechanical interactions. However, direct observations of subsurface multi-physical processes in bank slopes remain rare. Herein we present the design, implementation and evaluation of an innovative fiber-optic nerve system based on weak-reflection fiber Bragg grating to monitor a giant landslide located in the Three Gorges Reservoir region, China. The system is capable of measuring and imaging spatiotemporal distributions of temperature, moisture and strain along boreholes in near real-time. Such visual profiles offer unique insights into the subsurface thermo-hydro-mechanical link between external conditions and geotechnical deformation, making it possible to decipher the substantial trigger of accelerated movements. Multi-physical responses at depths of interest also enable us to better understand the evolution mechanism of reservoir landslides. Fiber-optic nerve sensing can synergize with remote sensing and surface-based technologies to build a space-sky-ground-subsurface integrated monitoring system for landslides.