Experimental study of frozen fringe characteristics

The objectives of the paper are to show the efficacy of a newly developed X-ray radiography technique for the study of frost heaving, and to discuss experimental data which reveal the characteristics of the frozen fringe. An open-system frost heave test was conducted for about 700 hours. Lead sphere position markers, in which thermocouples are installed, were placed every 5 mm along the axis of a cylindrical 97 mm long specimen. Seventy-four X-ray radiographs were taken during the test. These X-ray radiographs show ice lenses and the lead spheres clearly. The measured co-ordinates and temperatures of the spheres enable precise temperature profiles to be determined for each X-ray radiograph. By referring the temperature profile to the X-ray photograph, the thickness and temperature range of the frozen fringe are determined. The data obtained by this experiment include heave rate, water intake rate, thickness and temperature range of the frozen fringe, and strain rate distribution within the specimen. From these, the periods of in situ and/or segregation freezing and water movement are discussed.