Real-Time Prediction Method for Slope Failure Caused by Rainfall Using Slope Monitoring Records
Tomohiro Ishizawa†, Toru Danjo, and Naoki Sakai
National Research Institute for Earth Science and Disaster Resilience (NIED)
3-1 Tennodai Tsukuba, Ibaraki, Japan
The failure time of a slope is predicted by a method based on creep failure theory for slope displacement on natural slopes, embankments, and cutting slopes. These prediction methods employ several equations based on the relationship between the displacement rate (displacement velocity) and time. However, such methods harbor problems because the shape of the tertiary creep curve is affected by many conditions, and it is difficult to identify the phase of tertiary creep. This study examines the time change in the displacement rate of the slope and derives an index for identifying the phase of tertiary creep. Two models of large-scale composite granite slopes were tested by using a large-scale rainfall simulator. In the experiments, the slope displacements were monitored in real time. From these results, inflection points were found in the velocity of the slope displacement. It was found that the corresponding inflection points at different locations in the sliding soil mass occurred with the same timing. This paper discusses the effectiveness of the prediction method for slope failure time by using the inflection points of displacement rate in real-time monitoring records.
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