Effects of flow-bed interactions on barrier impact

Abstract

Debris flow mobility is governed by complex interactions at the flow-bed interface. These interactions may cause flow bulking and increase in momentum. Both factors need to be considered for the design of barriers installed along the flow path. In this study, channelized debris flow over a wet erodible bed impacting a terminal flexible barrier is modelled in a 28-m-long and 2-m-wide flume facility with 20o slope inclination in Hong Kong. Tests with flow volumes of 6 m3 and 9 m3 overriding both erodible and non-erodible beds are conducted. The change in normalised flow energy over the erodible bed section, the change in flow momentum and the impact dynamics on the terminal barrier is assessed.