Frozen sandy - clayey soils with readily soluble salts (chlorides) frequently occur in permafrost regions, particularly near by arctic sea coasts. The kinetics of the freezing process, higher content of the unfrozen liquid phase and its polymorphizm, the presence of saline fine crystalline pore and streaky ice, structural peculiarities etc., are responsible for essential differences between the properties of saline and non-saline soils. Major criterium for their differentiation is a critical (limiting) initial concentration of the soil saturating solution - Ccr. At an initial concentrations Ci < C cr saline and non-saline soils practically do not differ in terms of their electric, elastic and most other properties. Marked differences in properties and in their dependances on frequency, temperature, water content, lithology etc., begin to emerge at Ci > Ccr. Such soils are refferred to as saline soils. Experiment revealed that for quartz sand Ccr = (0.5-1) * 10-2 mole/l. It grows approximately linearly with soil dispersivness and clayeyness increasease being almost a hundred times higher for heavy clays (bentonite). Increase of the Ci > Ccr results in shorter electtric relaxation time (t), lower static dielectric permittivity (es), electric resistivity (r), elastic vawe propagation velocities (Vp,s), dynamic elastic moduli (E, G, K).
Laboratory studies have shown, that known monotonous dependences (decrease) Vp,s in sand-clay series for non-saline frozen soils acquire an extremum beginning from Ci > Ccr. Maximum velocity values have been obtained for saline frozen loams. Different decrease rates of elastic modulus values for sandy and clayey soils lead to intersection of the curvts of E, G, K as a fanction of Ci, i.e. frozen soils with a different lithology can have very closed magnitudes of the elastic moduli at certain salinity.
Elictic resistivity of frozen soil decreases with an increase of Ci > Ccr nevertheles, the monotony of their dependence on grain sizes remains intact. At the same time, concentrations Ci > (0.5 - 0.8)* 10-1 mole/l yield practically equal resistivity values for frozen soils with different lithology (except a heavy clays), at fixed temperatures, i.e. the impact of concentration and composition of saturating pore solution dominante in these cases.
Frequncy and temperature spectra for real (E'ef ) and imaginary (E"ef ) parts of effective dielectric permittivity for saline soils differ essentially from known spectra for non-saline frozen soils due to significant impact of macrodipole polarization in the discret domains of unfrozen pore solution. For instance, at Ci > 10-1 mole/l high E'ef values at low frequences remain practically unchanged (even for frozen sand) up to eutectic temperature (teu) of the saturating solution in the vicinity of which some maximum of E' are distinctly observed. In this case E'ef starts decrease only at t < teu. At high frequences (> 105 - 106 Hz) E'ef of saline frozen soils begins to decrease monotonously at the temperatures near by 0oC as there is for non saline soils.
Oksana P. Chervinskaya Industrial and Research Institute for Constructions Moscow, Russia. Yurij D. Zykov Industrial and Research Institute for Constructions Moscow, Russia. Prof. Anatoly D. Frolov United Scientific Council on Earth Cryology Russia Academic of Sciences Moscow, Russia. Telephone: (095) 930-2634 Fax: (095) 253-1192 E-mail: kvb@kvb.msk.ru (For A.Frolov)