Behaviour of saline frozen soils.

摘要

his thesis presents the results of an investigation of the distribution and mechanical behaviour of saline frozen soils. A better understanding of these soils will help the geotechnical engineer working in northern areas.;The first part of the thesis presents a database of the salinity measurements from the Northwest Territories. Correlations between salinity and physical properties show that salinity decreases with an increase in moisture content, and that high salinities are found in marine or glacial sediments associated with a period of marine transgression. The occurrence of saline permafrost was shown to be associated with the Quaternary geology.;Two aspects of the mechanical behaviour were investigated in detail; the deformation response under constant strain rate compression and the time dependent deformation response under constant stress compression. Three soils were studied at four different salinities: a fine uniform sand, a silty sand and a very fine silty sand at salinities of 0, 5, 10, 30 ppt.;For the constant strain rate tests, test temperatures were ;The strength of all soils was shown to decrease with an increase in salinity and temperature, or with an increase in unfrozen water content which was measured using time-domain reflectometry. Relationships between strength and temperature or unfrozen water content are presented.;Time dependent (creep) behaviour was studied at