Recently, debris flow disasters have become more frequent due to abnormal weather conditions. Flexible barriers are used as urgent countermeasures against debris flows after natural disasters occur. However, few studies focused on the effectiveness of flexible barriers as a countermeasure against debris flows. This study elucidates the trapping efficiency of flexible barriers by using different net shapes and mesh sizes. The results showed that trapping efficiency decreased by increasing mesh size. Additionally, the cross-sectional area of the net mesh influenced the trapping efficiency. Furthermore, the flexible barrier demonstrated a higher trapping efficiency compared to an undeformed net. This is due to net deformation during debris flow trapping and restoring forces associated with it.
