The experimental study on the uniaxial compressive strength of frozen silt with different salt content

The saline silt, which was collected from the Pingchuan district of Baiyin city, was firstly washed off salt, and then pure NaCl and Na₂SO₄ were added into the silt as the testing sample soil. Finally, the influences of salt on the uniaxial compressive strength and the failure strain were studied through uniaxial compressive tests at a constant temperature and a strain rate. The test results show that if the mass content is between 0 and 3%, as the NaCl content increases, the unfrozen water in frozen soil and the distance between soil particles increase, cohesive force and internal friction angle of soil particles decrease, so the uniaxial compressive strength decreases in an exponential form and the failure strain increases at first and then decreases. Due to the special chemical, different Na₂SO₄ contents play different roles in the change of uniaxial compressive strength of frozen soil. When the mass content is between 0 and 3%, with the increase of Na₂SO₄, the uniaxial compressive strength of frozen silt increases at first and then decreases afterwards. While the failure strain has completely opposite changing trend with the uniaxial compressive strength.