Strength of frozen soils during thawing

More than a third of the Earth's surface is subject to seasonal or prolonged soil frosts, and the recent warming of the climate requires revision of the construction standards in the conditions of permafrost because under heavy load in low-strength soils, there is a high risk of mobility of thawing rock and collapse of the construction structures, which is fraught with disastrous consequences. For design tasks it is necessary to know the behavior of frozen soils under certain changing conditions. This creates new requirements related to the degradation of permafrost and, as a result, the criteria for strength and stability of soils suitable for construction are changing. Calculation of loads during construction in the permafrost zone requires a special approach in each specific case, since it is impossible to make a single model in connection with the variety of soils and the history of their freezing. Soil typization does not give a clear picture at negative temperatures, since the transition "water-ice-water"in the soil changes the behavior of the grounds, and the unpredictability of climatic changes affecting this process greatly complicates the task. In the hydraulic laboratory of the RUDN University, a series of experiments was conducted for various types of soil subject to load, in order to determine the main parameters affecting the stability of soils during thawing, and to give approximate recommendations regarding the use of these soils as bases. © Published under licence by IOP Publishing Ltd.