THE EFFECT OF HEAT AND MASS TRANSFER ON PILE FOUNDATIONS IN SEASONALLY FROZEN SOILS

Abstract

The phenomenon of heat and mass transfer in seasonally frozen soils has a significant impact on the condition of pile foundations. Building structures built in such soils experience extremely negative consequences: freezing, frost heaving, vibration dynamics, thawing. Seasonally frozen soils occupy most of the territory of Kazakhstan, and in most regions the depth of soil freezing exceeds 1.5 m, there are settlements where the indicator reaches 1.9 m and in the north of the country – 2.74 m. The installation of foundations below the freezing depth leads to an increase in the cost of construction, requires additional costs for thermal insulation, ventilation, other materials and structures, and, moreover, does not always lead to a complete leveling of the negative effects of heat and mass transfer on the life and operating conditions of buildings, structures, railways and highways. Therefore, the efforts of engineers and specialists in the field of thermophysics are aimed at finding effective ways to solve the problems of deformation and destruction of foundations in seasonally freezing soils.The article attempts to identify the nature of the effect of heat and mass transfer on pile foundations in seasonally frozen soils based on a thermomechanical model. During laboratory tests, physico-mechanical tests were carried out, as well as heat and moisture transfer in the soil from the depth of the pile base to the surface of the soil were calculated.