Experimental study on mechanical properties of saline frozen silty sand

The triaxial compressive tests on saline frozen silty sand with the water content of 13% and Na₂SO₄ content of 0.5% were carried out at temperature of -6 ℃. The confining pressures ranged from 0.3 to 18 MPa. The results indicate that the influence of confining pressure on stress-strain curves is obvious at lower confining pressures, but with the increase of confining pressure, the influence gradually disappears; strength change with confining pressure can be divided into three stages: rapid growth stage of strength, slow growth stage of strength, decrease stage of strength; the initial tangent modulus E₀ and the secant modulus at 50% strength E_0.5 changing with confining pressure can be divided into three phases, two modulus growth with confining pressure in phase 1 and phase 2, and the change rate is larger in phase 2, decrease in phase 3, but the change rate of E_0.5 is smaller under the whole scope of confining pressure, so E_0.5 can be regard as a constant at a larger range of confining pressure in the engineering design if it is used as the deformation index, but with E₀, the effect of confining pressure must be considered.