METHOD FOR FREEZING AND MAINTAINING STABLE CONDITION OF PERMAFROST SOILS Russian patent published in 2024 - IPC E02D3/115 

FIELD: construction.

SUBSTANCE: construction on permafrost soils used to urgently increase the strength and deformation characteristics and maintain in a stable state of permafrost soils the base of the subgrade of railways and highways, civil and industrial buildings and structures during construction, operation and reconstruction. The method of freezing and maintaining a stable state of permafrost soils includes active and passive freezing in at least one two-pipe coaxial column buried in the soil, while before the freezing process begins, the closed circuit is filled with refrigerant, and this is carried out in two stages, and namely, the active and passive freezing stages, while the passive freezing stage follows the active freezing stage, while during active freezing, a refrigerant with a low boiling point under pressure is supplied to the external circuit of the coaxial column formed between the walls of the outer and inner pipes to a level corresponding to the minimum level refrigerant installed by thermal engineering calculations, the gas evaporating in this case is released into the environment, ensuring rapid freezing by removing heat from the column-soil system, when the required negative soil temperature is reached, the supply of liquid refrigerant and the release of evaporating gas is stopped; with passive freezing in the cold season, the refrigerant supplied under pressure to a predetermined level corresponding to the required volume of refrigerant for effective heat exchange, established by thermal calculations, while the external and internal circuits are filled with refrigerant, communicating through the open end of the inner pipe, and natural circulation of the refrigerant is ensured along a closed circuit, along the internal circuit of the coaxial column down, along the outer edge of the coaxial column to the top, and then up through the perforated holes made in the ground part of the central pipe, down along the contour of the coaxial column.

EFFECT: providing a one-time rapid freezing of the soil without the use of additional energy-dependent equipment and further maintaining the frozen state of the soil.

4 cl, 3 dwg