This study investigates the failure of collapse mechanisms and structural stability of the block stacking Sabo dam due to water and driftwood. A series of flume experiments were conducted to simulate the effects of driftwood under steady flow conditions and dam break conditions. The results indicate that the failure process initiates with the downstream blocks, leading to a cascade progressive collapse due to reduced self‐weight of the structure. Larger inter‐block gaps enhanced permeability under water flowing, reducing fluid forces and improving stability. However, when driftwood was present, these gaps became clogged, increasing fluid forces and triggering abrupt block failure. The findings suggest that since sand and driftwood are contained in the debris flow, it is important to eliminate gaps between blocks and increase dead weight, and that enhance dam resilience. Furthermore, connecting the crest blocks proved effective in restraining individual block displacement and allowed the structure to resist external forces as a single unit.

Key words

emergency measures, block stacking Sabo dam, woody debris, disaster experiments