SELECTION OF WORKING CONDITIONS AND SUBSTANTIATION OF OPERATING MODE OF FREEZING PIPES IN MAINTENANCE OF FROZEN WALL THICKNESS

The authors discuss artificial freezing of water-saturated rock mass during construction of mine shafts in terms of a simplified case of a single freezing pipe. The ice growing and holding stages are examined. Maintenance of a constant thickness frozen wall is simulated using the coolant temperature regulator model. The multi-criterion numerical modeling of freezing is implemented, and the time dependences are obtained for the coolant temperature at the ice holding stage. It is found that maintenance of the constant thickness of frozen wall requires that the coolant temperature in ice holding stage is exponentially increased at the power around –0.2. The ice growing stage temperature has no influence on the total energy efficiency of the freezing system.