A Continuous Tilt Sensor Based on UWFBG Technology for Landslide Real-Time Monitoring

Displacement monitoring is the key work of landslide disaster early warning. Distributed and real-time displacement monitoring can provide a more accurate and timely reference for landslide instability evaluation. However, existing technologies have deficiencies in combining distributed and real-time capabilities. Given this, a novel continuous ultra-weak fiber Bragg grating (UWFBG)-based tilt sensor is proposed. First, the tensile test is designed and carried out to investigate the strain transfer mechanism of the UWFBG cable. Then, calibration experiments are used to verify the monitoring performance of the sensors. Finally, the UWFBG tilt sensors are applied in the Majiagou landslide, a typical reservoir landslide located in Three Gorges Reservoir Area (TGRA). The results show that the sliding surface of the landslide is located at 33 m, and the maximum displacement value is 8.1 mm during the monitoring period. When the landslide is in a stable deformation state, the dynamic range of displacement is 1.4 mm. The UWFBG tilt sensors with distributed and real-time monitoring characteristics can achieve accurate landslide displacement measurement and provide outlets for early warning.