Data from: Experimental study on the benefits of nature-based solutions for debris-flow mitigation via synergistic eco-geotechnical measures

Research on nature-based solutions (NbSs) for mitigating debris-flow
hazards has increased interest in eco-geotechnical systems. Most studies
focused on the efficiency of isolated mitigation measures, while the
benefits and mechanisms of coordinated approaches remain unclear.
Consequently, this study proposed a novel approach to mitigating
debris-flow velocity, sediment transport, and energy by utilizing
tree-shrub mixed-vegetation filter strips (T-SMVFS) along S-shaped flow
paths combined with dams. The optimal design determination involved four
steps: 1) optimal T-SMVFS row and stem spacings were determined; 2)
S-shaped flow path parameters were set based on width ratios; 3) effects
of synergistic and individual measures on debris-flow reduction were
compared; and 4) a flow velocity reduction equation was constructed,
considering the influence of topographic features, vegetation planting
patterns, and debris flow properties. Results revealed that a completely
covered T-SMVFS with row and stem spacings of 10 and 6 cm in 1/50th scale,
respectively, exhibited the best reduction effects with 50% energy
reduction, 55% sediment interception, and 53% flow discharge regulation.
As the S-shaped flow path width increased, the flow reduction and sediment
interception rates decreased sequentially, while the transportation
capacity increased. Synergistic measures achieved 60% and 70% in energy
and sediment interception reductions, respectively, outperforming pure
geotechnical and biological measures. Comparisons between different
synergistic approaches indicated that a coupled S-shaped vegetation filter
strip with a 45% flow path proportion and a beam damweres more effective
in reducing debris flow. These findings provide a reference for subsequent
optimal mitigation solutions involving NbSs that integrate synergistic
eco-geotechnical measures.