Experimental Investigation on Impact Force of Dry Granular Flows on a Rigid Retaining Wall

Dry granular flow formed by the collapse of rock caused by earthquakes, weathering, and unloading results in severe damage to structures along its path. The mechanical parameters of a continuous impact on a rigid retaining wall were studied using an indoor experiment to measure the input parameters. The velocity and flow thickness of a granular flow impacting the retaining wall were continuously measured, and a continuous impact force model for normal impact force, tangential impact force, and impact force action height of dry granular flow is proposed here. The model calculated the continuous normal impact force, tangential impact force, impact force action height, movement, and accumulation index. The theoretical analytical solution was then compared with experimental results. Results showed that the impact force calculated by the proposed model is in agreement with test results. The calculated action height of the impact force was the closest to the test value when the position of the base reaction force was 1/2–2/3 the length of the accumulation area. The error of the continuous impact force calculated by the impact velocity using the energy conversion method was within ± 10%, which is more reasonable than the results obtained using the measured velocity in the test.