Earth’s Cryosphere, 2017, Vol. XXI, No. 3, p. 45-54
CORRECTNESS OF FORMULATION AND SOLUTION OF THERMOTECHNICAL PROBLEMS OF FORECASTING TEMPERATURE FIELD DYNAMICS IN THE GROUND BASE OF STRUCTURES
ON PERMAFROST
J.B. Gorelik1, D.S. Pazderin2
1 Earth Cryosphere Institute, SB RAS, P/O box 1230, Tyumen, 625000, Russia; gorelik@ikz.ru
2 OOO “Gazpromneft–Yamal”, 8B, 50 let Oktyabrya str., Tyumen, 625048, Russia; Pazderin.DS@tmn.gazprom-neft.ru
The paper discusses correctness of choice of boundary conditions for the upper and lower bounds of the computational domain, along with the problem of selecting the lower boundary position. It has been demonstrated by calculations that the incorrectly specified parameters of the upper boundary may lead to an unsubstantiated assertion about the cooling effect in the ground base of a structure, while the predicted thawing depth can be underestimated by several times in comparison with the actual one. Similarly, the “predicted” surface warming effect may not take place in reality. The wrong choice of the lower bound position of the computational domain can significantly exacerbate these effects. The proposed procedure for the correct choice of the upper boundary condition parameters for the soil surface-atmosphere interface is based on iterative matching of the condition parameters using a limited set of actual data on temperature at the zero amplitude depth and seasonal thaw depth, usually provided by typical geotechnical investigations. The study also addresses the problems of testing the developed algorithms and software products for the purpose of forecasting the thermal state of soils in the base of structures on permafrost.
Frozen ground, thermal engineering calculations, phase transition, active layer, boundary conditions, stationary solutions, depth of zero amplitude