Scaling principles of debris flow modeling using geotechnical centrifuge

The scale effect of debris flow hinders the in-depth understanding of debris flow dynamics. The geotechnical centrifuge can replicate the appropriate stress states of the prototype through an equivalent elevated centrifugal acceleration field. The geotechnical centrifuge provides a cost-effective solution for the scale effect of physical modelling of debris flows. Based on the existing dimensionless group of two-phase flows, a hierarchical scaling solution is proposed for the design of debris flow experiments in the centrifuge. It ensures that both the absolute values (i.e., absolute stresses) and the relative values (characterized by the dimensionless group) in the model match those in the prototype, so that the fundamental physical processes in debris flows can be captured. Furthermore, the technical issues, the Coriolis effect and the influence of the real 1g gravitational acceleration, are quantitatively evaluated. To minimize these effects, a larger effective centrifuge radius and a lower angular velocity are recommended in the design of debris flow experiment using centrifuge. This study provides a significant theoretical and technical reference to the small-scale and large-scale physical modelling, and centrifuge modelling of debris flow problems.