An experimental determination of the relationship between the minimum height of landslide dams and the run-out distance of landslides

• Published in: Landslides 2021-06, Vol.18 (6), p.2111-2124
• Main Authors: Chen, Kun-Ting, Chen, Tien-Chien, Chen, Xiao-Qing, Chen, Hua-Yong, Zhao, Wan-Yu
• Format: Article
• Language: English
• Subjects: Agriculture; Civil Engineering; Climate change; Climatic conditions; Dam failure; Dam stability; Dams; Disasters; Distance; Earth and Environmental Science; Earth Sciences; Earthquakes; Emergencies; Emergency management; Emergency preparedness; Emergency warning programs; Friction resistance; Future climates; Geography; Global climate; Height; Laboratory experiments; Lakes; Landslide warnings; Landslides; Landslides & mudslides; Mountain regions; Mountainous areas; Mountains; Natural Hazards; Original Paper; Parameters; Rain; Rainfall; Risk assessment; River channels; Rivers; Seismic activity; Slopes; Stability analysis
• ISSN: 1612-510X; 1612-5118
• DOI: 10.1007/s10346-020-01605-1

Landslides frequently occur on mountain slopes due to earthquakes and rainfall. When a landslide occurs near a river, the landslide mass moves at a certain speed towards the river channel and eventually stops at the channel either due to frictional resistance or by being blocked by the upslope on the opposite bank of the river. If the width of the river channel at the landslide site ( B W ) is narrow and the volume of the landslide ( V L ) is sufficient, the landslide may block the river channel, resulting in landslide dams. Landslide dam is a significant hazard in mountainous area, when dam failure will cause severe destruction and affect downstream area. The frequency, scale, and disaster of landslide dam will be more serious than before based on global climate change. To reduce disasters caused by landslide dams, rapid assessments of dam stability and dam-break discharge must be conducted in the early stages of the formation of landslide dams. One of the essential parameters for these assessments is the minimum height of the landslide dam ( H D min ). However, landslides may occur in remote, inaccessible mountainous areas where the geometrical parameters of landslide dams may not be immediately obtained, making it difficult to perform emergency risk assessments of barrier lakes. The magnitude of H D min changes due to the effects of the run-out distance of the landslide ( L run ‐ out ) and B W , but a quantitative relationship has not been reported in the literature. Hence, this study investigated the effects of V L , the slope angle ( θ S ), the maximum height of the landslide ( H L ), B W , and other parameters on H D min through laboratory experiments. The relationship between L run ‐ out , B W , and H D min was determined, and a dimensionless method for evaluating H D min was established. This method can be applied to predict the minimum height of landslide dams when the position of the landslide is known. Additionally, when landslide dams form but H D min is not known due to difficulties in on-site study, this method can quickly assess the height of the dam and provide an assessment of the risks related to the landslide dam. This greatly reduces the uncertainties associated with the prevention and emergency management of landslide dams, and can assist government authorities to set up the disaster early warning plans of landslide dam under future climate change condition.