Case study: frost heave and thaw settlement under an ice rink

This paper presents the results of a case study where various methods were used to estimate the frost heave and the thaw settlement of a frozen ground beneath the ice rink facility in Myllypuro, Helsinki. Several undisturbed soil samples were taken from the proximity of the site and characterised for frost susceptibility. Laboratory frost-cell tests were conducted on soil samples from different depths to estimate the possible future frost heave and thaw settlements of the frozen ground. Frost heave and thaw settlement were also calculated from various empirical formulations and compared with the estimations based on the laboratory test results. The thaw settlement estimations from the frost-cell test results was 1·84 m (∼28% of the total frost depth), which was similar to the results from the empirical formulations. The calculated frost depth and frost heave at the end of 30 years were 6·39 m and 622 mm respectively. This was in good agreement with the on-site measurements taken immediately before the renovation, after about 30 years of continuous operation.