A Full-Scale Model Test for Predicting Collapse Time Using Displacement of Slope Surface During Slope Cutting Work

It is important to predict an onset of slope failures or rock falls for the occupational safety because about 15–20 workers were killed by these every year in Japan. Approximately half of the victims suffered from slope failure during slope excavation construction. In this research, in order to predict the time of slope failure during an experimental testing on a full-scale model slope was conducted, and the displacements of the slope surface were monitored during the slope excavation. The surface displacements rapidly increased with the elapsed time after the excavation, and the relationship between the displacements and the elapsed time included an exponential function just before the collapsed. We validated that the time of slope failure could be predicted by the relationship between the acceleration and the velocity of the obtained slope surface displacements. However, in order to predict the time of collapse, the data was required to compute only 2 s before the collapse. Therefore, we realised the importance of providing advisory and warning signal to give workers enough time to escape the slope failures. We have discovered that by computing the inverse of velocity of slope surface displacement, advisory and warning signals can be provided 2 min before the collapse.