Frozen soil boundary control system

The utility model provides a frozen soil boundary control system, comprising a low-temperature brine circulating sub-system, a hot brine circulating sub-system and a temperature monitoring sub-system, wherein the low-temperature brine circulating sub-system comprises a cooling water device, an ammonia circulating device and a low-temperature brine device which are orderly connected; the ammonia circulating device comprises an evaporator, an ammonia compressor, a condenser and a throttle valve which are orderly connected to form a loop, and exchanges heat with the cooling water device through the condenser, and exchanges heat with the low-temperature brine device through the evaporator; the low-temperature brine device comprises a freezer; the freezer is arranged in a soil body at the periphery of a well wall; the hot brine circulating sub-system comprises a hot brine circulator; and the hot brine circulator is arranged in the soil body between the freezer and the well wall. By adopting the frozen soil boundar