Author(s): S. P. Chee; M. R. I. Haggag

Linked Author(s):

Keywords: No Keywords

Abstract: The bottom thickening of ice covers caused by the migration of ice blocks beneath the covers is discussed with reference to the instability characteristics of ice floes as they approach the leading edge of the former. Undercover ice runs can broadly be classified from the manner in which the ice blocks become unstable as they approach the upstream rim of the ice cover as to whether the floes will first submerge bodily followed by underturning to get beneath the cover or simple translation with further submergence to pass below the cover. A second category refers to blocks which start off the instability sequence by initial rotation before underturning or additional sinking to move below the cover. Once the blocks have arrived below the cover, the mechanics of pushing and displacement takes place as the blocks move further downstream of the cover. A second thickening of the cover can take place under favourable hydraulic conditions by a repetition of the above cover formation processes. Ice block instability due to sinking and spatial tilting as the mode of submergence was analysed. With the aid of laboratory observations using wooden blocks of varying thicknesses and lengths, experimental relations were derived to establish instability criteria.

DOI:

Year: 1978