Influence of water and salt contents on strength of frozen soils

In order to study the mechanical properties of frozen soils, a series of uniaxial compressive strength tests are conducted with water content of 9.5%, 11.5%, 13.5%, 15.5%, 17.5% and saturated conditions at -10℃, and with salt content of 0.2%, 1.6%, 3.0%, 4.4%, 5.8%, 7.2% and 8.6% at -15℃ respectively. According to the test results, the stress-strain relationship, uniaxial compressive strength and destruction type are strongly affected by the water and salt contents of the soils. The test results show that the uniaxial compressive strength increases with the increasing water and salt contents firstly, then it decreases rapidly after reaching its peak. The water content corresponding to the peak strength is 17.5% regardless of the salt content and dry density of the soils. But the salt content corresponding to the peak strength varies under different water contents: under the water content of 13.5%, the strength reaches its peak under the salt content of 4.4%; under the water content of 15.5% and 17.5%, the strength reaches its peak under the salt content of 5.8%.