The Load-Carrying Capacity of Depth-Processed Snow on Deep Snowfields
摘要
Extensive experiments have been conducted by the Naval Civil Engineering Laboratory, Port Hueneme, California, u.,s.A., to produce high-strength snow by mechanical acceleration of the natural metamorphic processes occurring in snow. Snow roads have been developed for vehicles weighing up to 70 000 pounds (31 752 kg) with high-flotation tires inflated up to 30 psi (2.11 kgJcm2). Snow runways have been developed for aircraft weighing up to 135000 pounds (61236 kg) with main-wheel inflation pressures up to 95 psi (6.7 kgJcm2). A punching failure directly under the wheel is the principal typ. ~ of failure occurring under a moving-wheel load on compacted snow. Based on this type of failure, a confined shear test is presently used to approximate the unit load-carrying capacity of compacted snow. For more precise field measurements, a rolling-wheel test vehicle is being developed to simulate moving vehicle and aircraft wheel loads on snow. A 2-layer, 32-inch-thick (80 cm) experimental compacted-snow runway on the Ross Ice Shelf, Antarctica, was tested with aircraft during the summer season of 1964-65. As snow is a temperature-dependent material, the strength of the runway varied with changeR in temperature at the test site. Its average total load-carrying capacity, however, exceeded that required for the test aircraft at all times. Because of processing misses, areas of low-strength snow in the top layer resulted in runway failures during the initial aircraft tests. Repair of these areas permitted multiple landings, takeoffs, and taxi runs on wheels in the final aircraft test. I.