Research on the erodibility of landslide dam materials based on flume test

Abstract

Landslide dams are usually formed by river blockages with massive amounts of materials from avalanches, landslides, and debris flows. The breaching of landslide dams may cause mega floods, posing great threats to people and infrastructure downstream. The important role in evaluating the breaching of landslide dams is the erodibility of dam deposits. In this study, ten grain size distribution with different characteristics (e.g. unit weight, fines content, d 50 ) were extracted based on 7 landslide dams. The laboratory flume apparatus, with a length of 5 m and a width of 0.4 m, were used to study the erosion rate of materials under six water flow rates. The test samples were collected, dried, and weighed before and after every single test to calculate the erosion rate. Results indicated that the erosion rate increases with the increase of flow velocity and shear stress. The relationship between erosion rate and flow velocity and shear stress is almost linear. Both the critical incipient velocity and critical shear stress have poor correlations with soil property, which means these two parameters cannot be predicted by one or two influence factors since it is affected by multi-factors. The work can serve as a basis to predict erosion rate of dam materials and analyze the breaching of landslide dams.