Ice Structures For Airfield Construction PDF Download

New methods and equipment for thickening and strengthening natural sea ice are needed to advance polar operational capabilities. Of the basic categories of techniques for inducing ice growth (ice injection, cold fluid injection, and recirculating fluid), one recirculation technique-the convection cell-was found to best fulfill the requirements for polar applications. Other techniques imposed greater work or energy requirements. Two basic convection cell systems were laboratory tested: liquid convection and liquid-vapor phase convection. At a 30F air temperature, the Balch liquid convection cell produced 7.75 inches of ice in 90 hours while the Long liquid-vapor phase cell produced only 2 inches during the same time period. Because the liquid convection cell was found to be more effective at the mean polar air test temperatures than the two-phase cell, it was selected for field testing at Point Barrow, Alaska. The initial field tests at Point Barrow during the spring of 1969 demonstrated the excellent potential of the Balch-type liquid convection cell for thickening, stabilizing, and anchoring near-shore ice structures. Cells suspended in seawater produced ice along the entire submerged length; the production rate was dependent on the seawater temperature, the prevailing air temperature, and the thickness of the ice mass around the cell. In FY70 convection cells were used to form two grounded ice structures offshore at Point Barrow to permit study of their long-term stability. Laboratory research to improve cell performance and field application has resulted in the development of two new liquid convection cells: a simplified vertical convection cell and a horizontal convection cell. (Author).