Landslide Field Experiment on a Natural Slope in Futtsu City, Chiba Prefecture

Climate change has contributed to increasingly frequent heavy rainfall events across Japan, increasing the risk of landslide disasters on steep slopes. Despite the urgency of this issue, few studies have assessed actual changes within a slope in real time during simulated rainfall-induced landslides. This study employed a rainfall simulator to study slope changes and relevant mechanisms in a sandy slope in Futtsu City, Chiba Prefecture. Inclinometers, extensometers, piezometers, and several video cameras were installed along the slope to capture slope movements, groundwater levels, and visual data during a simulated rainfall event leading to a landslide. Changes measured in groundwater flow and soil structure were attributed to the formation of soil blocks. Slope instability was promoted by increased groundwater levels when the discharge capacity was no longer able to accommodate the increasing precipitation rates, resulting in the occurrence of a landslide. The data and video captured in this experiment will be widely disseminated among several cooperating organizations and is also intended to serve as material for disaster-awareness videos to promote public safety.