In this study, the correlation between slope deformation and time in a 3-h consecutive deformation curve was used as an early warning mechanism before landslide occurrence. This approach is called the delta-ratio method, wherein curves of displacement versus time are plotted, with segments of equal time set to 1 h. As the displacement of a curve increases, the segments are subtended by the larger displacement of a 1-h interval, as evident from numerical analysis with PLAXIS. This study analyzed the delta ratio of on-site monitoring data collected using surface extensometers in Taiwan’s Gugulun and Guanghua landslide areas, where landslides occurred in 2021 and 2022, respectively.
The expert system using the delta-ratio method revealed a displacement velocity ratio of 1.2. V0 was 4mm/h, and V1, V2, and V3 were 4.8, 5.76, and 6.91 mm/h, respectively. Overall, the expert system provided a landslide warning 12 h in advance when velocity thresholds were set at V1, V2, and V3.
Key Words: Landslide warning, Expert system, Large-scale landslide monitoring