An evaluation of GPR techniques for analyzing the safety of Interior Alaskan ice roads under varying river ice and environmental conditions

Abstract

Ice roads and bridges are necessary routes to transport heavy equipment, supplies and food in the winter months to and from isolated cold region communities off the road system. Ice roads allow for community members to avoid the high costs of air shipments and obtain equipment and vehicles that would otherwise not be available. These ice roads traverse frozen bodies of water (e.g., rivers, estuaries, and lakes), and require extreme safety when driving over. To achieve this, calculations are frequently completed to determine the maximum acceptable loading on the ice cover. River ice tends to have increased safety concerns and uncertainty for travel that stem from warmer air temperatures and other factors such as precipitation, snow drifting, and ice cover forming differently each year. The necessity of obtaining time intensive ice thickness measurements by hand puts the responsible personnel at considerable risk of injury or fatality. Ground penetrating radar (GPR), which has gained much popularity in the last few decades, is a quicker and more effective non-invasive method for measuring ice thickness and other properties. The GPR system was tested for its accuracy in measuring ice thickness on common transportation routes on the Yukon River and the Tanana River. Identification of varying ice type layers in river ice cover using GPR was also attempted. While layers could not be identified using the 450 MHz and 750 MHz central frequency antennas, an accuracy analysis of GPR ice thickness measurements under various environmental conditions was completed. This analysis contributes to a comprehensive understanding of the safety of ice roads for community members in remote northern villages and provides the basis for further research on identifying layers in river ice cover.