Abstract: Flexible debris flow barriers are important engineering measures to prevent debris flow disasters. The existing prevention structures are mainly in the form of closed barriers, which are prone to blockage with poor regulation abilities. Therefore, we proposed open flexible debris flow barriers to overcome the above shortcomings. Based on theoretical analyses and physical model tests, the research on the regulation performance of the open flexible debris flow barriers was carried out, and the theoretical formulas for the velocity attenuation rate, run-up height, and blocking rate of debris flows were deduced. The results show that compared with the closed flexible debris flow barriers, the improved structure has a good self-cleaning effect and can effectively control the peak velocity of debris flows. The calculation results through the derived non-dimensional theoretical formulas are in good agreement with the physical test results. The velocity attenuation rate, run-up height, and blocking rate of debris flows are mainly controlled by the relative open height, dimensionless flow depth, relative density of debris flows, and the Froude number. The velocity attenuation rate and blocking rate are negatively correlated with the relative open height, and positively correlated with the relative density of debris flows. The run-up height is negatively correlated with both the relative open height and the relative density. The above research can provide theoretical and technical support for the application of open flexible barriers in debris flow prevention and control projects.

Key words: debris flow, open flexible debris flow barriers, velocity attenuation rate, run-up height, blocking rate