Preliminary study of debris flow impact force on a circular pillar

Abstract

This paper presents results from a series of preliminary tests in a flume model, where impact forces on a circular pillar from debris flow is measured. The flume model is 0.3 m wide and 9 m long. It comprises of a run-out channel and a deposition area. A 75 mm diameter hollow circular steel pillar equiped with a load cell is placed at the end of the run-out channel, perpendicular to the flow. Nine tests were conducted with different volumes of debris which resulted in varying discharges. In all the tests, the debris flow material that is a mixture of soil and water, was made to have solids concentration Cs of 60% by volume. Despite some scatter in the data, the results suggest that the impact force on the pillar increases linearly with the debris flow discharge. The recorded impact forces are also compared and discussed in light of the analytical solutions suggested in the literature.