Fundamental study on slope failures, failure Shapes, and frequency distribution using sandpile experiment

抄録

Most of the slopes that are found in nature, occurred naturally without any intervention by humans. Failures of these slopes can be triggered due to earthquakes and heavy rainfall. The failure characteristics such as the slip surface shape and the collapsed magnitude vary greatly due to the dominant direction of seismic motion, heterogeneity of the ground, and unsteady infiltration of rainfall. Although an extensive number of experimental studies have been accomplished to understand slope failure, it is not enough to grasp the probabilistic nature of slope failure phenomena.

In this study, experimental and statistical analysis was carried out using the sand pile model to understand the slope failures and their magnitude. The sandpile model is a model that gradually distributes sand to a pile of sand and repeatedly observes the collapse of the sandpile. The experiment using of silica sand no.8 (fine sand) was carried out with different base plates of 5cm to 12cm at a constant rate of adding sand. Shape variations of the sandpile were captured with a depth camera.

Results show that the number of slope failures decreased when the diameter of the sandpile increased. However, slope failure mass and time interval between consecutive slope failures increased. The statistical distributions of slope failure mass and time intervals exhibit deviations from a normal distribution pattern. Notable geometric changes were predominant on the apex of the sandpile. Results conclude that the magnitude of the slope failures and the time taken to occur a failure depends on the metastable slope angles.