Determination of parameters of anti-heave structures of the subgrade taking into account the freezing system

Background: in the Northern Hemisphere, during the construction and operation of railways, one of the pressing problems is frost heaving. One of the key factors influencing the amount of frost heaving is the occurrence of groundwater relative to the freezing front of the subgrade soils, which is not fully taken into account by existing approaches to determining the parameters of anti-heaving structures. This factor is usually characterized by freezing regimes, there are two of them - open and closed freezing systems. An open system is characterized by the proximity of groundwater to the freezing front, at which there is a constant influx of water (migration) to the zone of phase transitions, which makes the process of frost heaving unpredictable, and the determination of the frost heave ratio incorrect. A closed freezing system assumes the absence or deep location of groundwater (the difference in the level of the freezing front and groundwater exceeds the height of the capillary rise of water).

Aim: development of a method for calculating the parameters of anti-heaving. structures depending on the freezing regime of railway subgrades.

Materials and Methods: comparative analysis of methods for calculating the parameters of anti-heaving structures, experimental studies of the process of frost heaving in an open system of freezing of clay soils.

Results: based on experimental studies of freezing regimes, a differentiated approach to assessing the characteristics of frost heaving is proposed, taking into account the peculiarities of the frost heaving process.

Conclusion: the proposed method with a differentiated approach compares favorably with existing ones, allowing to reduce the consumption of building materials when designing anti-heaving measures.