Rate effects during ice scour in sand

This study is focused on the prediction of ice scour loads on a cohesionless seabed in saturated and dry conditions by means of reduced scale physical model testing. The influence of different soil parameters such as the soil permeability and the relative density have been studied in the laboratory under 1g conditions over a range of scouring depths, scouring widths and drifting velocities of an iceberg model. The effect of the drifting speed on the scouring loads was found to be important: a sandy seabed scoured by an iceberg with a mean drifting speed of 0.2 m/s can generate scour loads twice as large as the static loads at prototype scale. The methods used currently to predict ice scour loads consider only the static loads under drained conditions, lower bound, even though some of the methods have been calibrated or compared against experimental results under saturated conditions. In order to calculate the upper bound of the scour loads, the model described in this paper is proposed, which takes into account the undrained (or partly-undrained) responds of a sandy seabed.