The purpose of the present invention is to provide an artificial ground freezing method having good coolant thermal efficiency without a gas-phase coolant being released into the ground or into the air. For that purpose, the present invention has: a freeze pipe (1: casing) for freezing the ground buried in the ground and a coolant circulation pipe (2) provided on the inside of the freeze pipe (1), wherein the coolant flowing inside the coolant circulation pipe (2) is carbon dioxide; and a coolant apparatus (10) that cools and supplies the carbon dioxide to the coolant circulation pipe (2), the coolant circulation pipe (2) comprising a first coolant circulation pipe (2A) on which a plurality of micro-coolant passages (2A delta) is formed, wherein the tip portion (tip portion in the ground) of the first coolant circulation pipe (2A) is connected to a plugging member (3: bottom socket) that connects the plurality of micro-coolant passages (2A delta) of the first coolant circulation pipe (2A) to a coolant supply side and coolant return side.

The invention relates to a method for producing a contiguous ice body in a ground region, wherein first cooling lances are inserted into the ground region in which the contiguous ice body is to be produced in the presence of a flow of a fluid flow medium flowing through the ground region, in particular in the form of groundwater, wherein a first coolant is introduced into the first cooling lances, and wherein furthermore at least one second cooling lance is introduced into the ground region on a side of the first cooling lances facing the flow and a second coolant, which has a temperature that is lower than the temperature of the first coolant, is introduced into the at least one second cooling lance in order to support the formation of a contiguous ice body that surrounds all of the cooling lances.

The invention relates to a method for producing a contiguous ice body in a ground region, wherein first cooling lances are inserted into the ground region in which the contiguous ice body is to be produced in the presence of a flow of a fluid flow medium flowing through the ground region, in particular in the form of groundwater, wherein a first coolant is introduced into the first cooling lances, and wherein furthermore at least one second cooling lance is introduced into the ground region on a side of the first cooling lances facing the flow and a second coolant, which has a temperature that is lower than the temperature of the first coolant, is introduced into the at least one second cooling lance in order to support the formation of a contiguous ice body that surrounds all of the cooling lances.