Stability Analysis of Floating and Submerged Ice Floes

The mathematical model is based on the moment equilibrium of an ice floe resting beneath a uniformly thick ice cover. It is argued that the expression derived for incipient motion of ice block is similar to the relation developed for the stability of prisms resting on the riverbed. The critical thickness, densimetric Froude number for floe transport is compared with that for the submergence of a floe at the upstream end of an ice cover, and with Ashton’s streamwise force balance analysis for ice floe stability beneath an ice cover. A nondimensional graph (Froude number versus block thickness-flow depth ratio) is presented to summarize the results. The analysis presented herein indicates that fragmented ice covers thicken generally by internal collapse rather than by transport of floes beneath the floating cover.