Solution of the Moisture Phase Transition Problem in the Insulation and Soils near Pipelines

The analysis of various approaches to the heat conductivity modeling in soils with phase transition based on Stefan problem is provided. Herein the analytical solution for Stefan problem is received only for special cases.The approximate methods of mathematical modeling of heat exchange in soils and construction materials based on the Stefan problem without initial data are offered. The found analytical solution can be a basis for approximate solutions of a wide range of heat exchange problems at harmonious oscillation of temperature on one of the borders. The mathematical apparatus for estimating problems solution of freezing and melting in areas with plane-parallel and axial symmetry is considered. Solutions for applied problems of constructions building and operation in the permafrost conditions are provided