THE AMOUNT OF UNFROZEN WATER IN SALINE SANDY SOILS
Currently, due to the intensive development of the Arctic coast, the assessment of the temperature regime of frozen saline soils, which are used as foundation for the construction and operation of complex engineering structures, is becoming a topical issue. Due to the higher content of unfrozen water in them, saline frozen soils are less durable than unsalted ones. The salinity of soils has a great influence on the heat and mass transfer and physical-mechanical properties of such soils. The main contribution to the change in these properties is made by the unfrozen water content. As you know, amount of unfrozen water depends on the freezing temperature, the concentration of the pore solution and the initial moisture content. This paper presents the results of experimental determination of the amount of unfrozen water in saline sandy soil as a function of temperature. Experimental studies were carried out on samples of river sand from the banks of the Lena River. The sand samples were salted with a solution of sodium chloride, the concentration of which varied from 0 to 20 %, the initial moisture content varied from 4,2 to 20 %. The amount of unfrozen water at different temperatures is determined by the method of continuous heat input developed at the V.P. Larionov Institute of Physical and Technical Problems of the North SB RAS. Using the experimental data obtained, a formula is derived that allows calculating the amount of unfrozen water at any change in the initial moisture content, temperature and concentration of the pore solution. A comparison of the calculated data with the experimental data obtained showed a good agreement. The resulting formula is applicable only for saline sandy soils, because the influence of soil dispersion is not taken into account.