Ice Ride-Up and Pile-Up on Shores and Coastal Structures


  • F. T. Christensen


Ice pressure, ice ride-up, ice pile-up, shores, coastal structures, design value


Simple techniques for selecting design ice ride-up and ice pile-up phenomena on beaches and coastal structures, such as breakwaters and bridge abutments, are outlined. The size of the ice pieces breaking off when the floe interacts with the slope is determined in a static analysis. Ride-up and instabilities leading to pile-up are examined. Two conceptually different relations between driving force and pile-up height arise from different mechanical models of the piling-up process. Design values are estimated by limiting the pressure within the advancing ice sheet to the horizontal failure pressure, which is generated as a floe when significant kinetic energy impacts a shore or a sloping coastal structure. Subsequent use of ALLEN'S (1970) formula gives a good estimate of maximum pile-up heights for given ice conditions. This implies that the entire pile-up must be pushed upward. Limiting heights based on the forces required to overcome gravity of only the advancing ice and friction, as proposed by KOVACS and SODHI (1980), give unrealistic pile-up heights. This presumes that the horizontal ice failure pressure is substituted for the unit driving force, and no other limitations or instabilities in the piling-up process are considered. Their model is suited for plane situations, where the ice velocity is nearly zero and the pressure is limited by driving forces rather than by the failure pressure. A limit must be added to their pile-up process model corresponding to buckling failure of the train of pre broken ice blocks riding up the seaward face of the ice pile-up.