Effect of Salinity on Moisture Migration in Artificially Frozen Ground

The authors analyze the influence exerted by content of common salt in pore space in frozen ground on moisture migration processes. The scope of the analysis encompasses three types of ground (clay, chalk and clayey sand) typical of freezing depth in shaft sinking at potash mines. It is found that the increase in salinity decreases intensity of frost heaving, except for a zone of small concentrations (to 0.0035 kg of salt per 1 kg of dry mineral). The total mass of salt transported to the freezing front grows nonlinearly with the increase in the initial salinity. The obtained results are theoretically interpreted using Darcy’s law for moisture migration rate, and the convective diffusion equation for salinity. It is shown that the key parameter to define the non-monotonous behavior of moisture migration toward the freeze front is the relative hydraulic permeability of ground, which in a complex manner depends on salinity.