Abstract:

In order to study the effects of precipitation on the landslide activities, the underground erosion of a typical crystalline schist landslide of Japan-the Zentoku landslide and its relation with the landslide movement are studied by employing extensometers, three-dimensional displacement meters and underground sediment discharge meters on the site. Based on the results of long-term observation, two main types of underground erosion are defined. The observation data indicate that the seasonal concentrated heavy rainfall is the main factor of inducing the significant underground erosion that can cause the abnormal activities of Zentoku landslide. The relation between underground erosion and sliding mass movement shows that the effects of underground erosion present different features on different sliding blocks. Especially, for the sliding block being of shallow sliding plane (10-20 m), the influence of underground erosion is most outstanding.

Key words: underground erosion, landslides, crystalline rocks, rain