Link for citation: Bogomyagkov A.V.,  Pugin A.V. Improvement of the mathematical model of heat and mass transfer in frozen soils implemented in the FrozenWall program. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 2, рр. 164-174. In Rus.

The relevance of formulation and numerical implementation of heat and mass transfer model in frozen soils considering mine shaft construction is caused by a number of technological factors and features of artificial ground freezing procedure. Correct calculation of artificial ground freezing for specific practical cases is impossible without taking into account such factors as variable mode of operation of the freeze pipes, presence of two freezing contours, different lengths of the supply pipes of the freeze pipes, heat exchange with the space of the mine shaft of variable depth, formation of cavities in the volume of frozen soils due to soil fallout, heat generation from hardening cement mortar, pore water filtration. These factors are taken into account in the heat and mass transfer model implemented in the specialized program FrozenWall, designed for thermotechnical calculation of artificial ground freezing and developed with the participation of the authors of the paper. The main aim of this work is to describe the improvements made to the algorithms of the FrozenWall software in the course of monitoring the state of the frozen wall on the vertical shafts of potash mines under construction. The objects of study are frozen soils around the potash mine shafts under construction. Methods included experimental temperature measurement in thermal control boreholes, data processing, mathematical modeling of artificial freezing of soils, parameterization of the heat transfer model in soils according to field observations by solving the inverse Stefan problem. Results. In the course of the modernization in the FrozenWall program, the algorithms were added that take into account such technological factors as unstable operation of freeze pipes, presence of two freezing contours, different lengths of the supply pipes inside the freeze pipes, heat exchange with the shaft space, formation of cavities in the volume of frozen soils due to rock outbursts, heat release from hardening cement mortar in the shaft under construction, filtration of pore water. Taking into account these factors, it becomes possible to develop new technical measures aimed at ensuring the efficiency of the construction of mine shafts in difficult hydrogeological conditions and possible emergency situations.