A study on determination of the frost depths for building foundations in the Central Anatolia Region of Turkey

The building foundations should be designed below frost depth due to the harmful effects of frost-related problems. In this study, the climate and geological properties of the Central Anatolia Region in Turkey were presented, and the frost depths of this region were predicted with Stefan equation, modified Berggren equation, and Chisholm-Phang equation for different soil classes under building foundation. Moreover, grey correlation analysis was used to present the correlation degree between the frost depths and its influencing parameters: surface freezing index, annual average temperatures, the average thermal conductivity of foundation soil, dry unit weight of foundation soil, the water content of foundation soil, and the number of freezing days. In addition, based on the results of grey relational analysis, each parameter in the basic frost depth equation was expressed by using multivariate regression analyses, and a new model was established. To validate the predicted data by the frost depth empirical methods, the actual frost depths proposed by the Republic of Turkey Directorate-General for Highways were compared with the predicted results. The results showed that the modified Berggren method exhibited the best performance, followed by the Stefan method, and the Chisholm-Phang method with the poorest performance. Furthermore, the annual average temperatures and the number of freezing days have more effect than other parameters on the frost depths. The developed model can be effectively used to calculate the frost depths of different soil classes with 0.9655 of the R 2 .