Analysis of Dam Characteristics and Failure Trend of Landslide Dams With Different Materials: Field Investigation

Abstract

Landslides can block rivers and create natural dams that pose significant flooding hazards to upstream and downstream. Variations in dam materials and geometries play a critical role in controlling breach initiation and failure processes, thereby complicating failure assessment. As a result, previous studies, typically based on laboratory experiments or individual case analyses, have provided relatively few systematic interpretations validated by field observations. Based on the 16 field cases from Southwest China and 30 documented Italian cases, clay content and characteristic particle size are adopted as material descriptors and landslide dams are classified into three types: rock landslide dams (RLD), rock–earth landslide dams (RELD), and earth landslide dams (ELD). Result show the difference in dam material caused by the dam‐forming processes (slide vs. flow) is clear. Specifically, RLD are boulder‐supported frameworks with higher resistance to erosion, whereas ELD are finer and more susceptibility to erosion. RELD display intermediate material properties between these end members. In these cases, regional contrasts are observed, with cases from Southwest China tending to be steeper and taller than those reported from Italy. Based on these results, the failure trends of three types of dams are discussed, together with the threats to stability faced by long‐lived dams. Existing stability indices are recalibrated using the field data set to incorporate material type, yielding improved assessment performance. This framework provides a field‐based reference for stability assessment of landslide dam in Southwest China.