Abstract. Natural as well as fill slopes are commonly found in Hong Kong, China, and
many other countries, and slope failures with the subsequent debris flows
have caused a serious loss of life and property in the past until now. There
are various processes and features associated with debris flow which
engineers need to know so as to design for the precautionary measures. In
this study, experiments on flume tests, friction tests, deposition tests, and
rebound tests were carried out for different sizes of balls to
determine the parameters required for the modelling of dry granular flow.
Different materials and sizes of balls are used in the flume tests, and
various flow pattern and segregation phenomena are noticed in the tests.
Distinct element modelling (DEM) of dry granular flow is also carried out for
the flow process. It is found that for simple cases, the flow process can be
modelled reasonably well by DEM, which is crucial for engineers to determine
the pattern and impact of granular flow, which will lead to further study in
more complicated debris flow. From laboratory tests, large-scale field
tests, and numerical simulations of single- and multiple-material tests,
it is also found that the particle size will be the most critical factor in
the segregation process during granular flow. It is also found from the
laboratory tests and numerical simulations that a jump in the flume can help
to reduce the final velocity of the granular flow, which is useful for
practical purposes.