Freezing-thawing behaviour of saline soil with various anti-saline measures

Abstract

In order to investigate anti-saline effect of various measures, the physical models composed of saline soil and crushed-rock layer, aeolian sand layer, impermeable geotextile and without measure were established, respectively. The test results indicate that crushed-rock layer, aeolian sand layer and impermeable geotextile can efficiently prevent moisture and salt from migrating. Moreover, they can efficiently alleviate frost heaving and salt expansion. A comprehensive measure, composed of crushed-rock layer, impermeable geotexile and aeolian sand layer, is proposed. Based on the theories of molecule motion and the phase transition, the migration mechanism and crystallisation rules of water and salt are investigated, and the amount of ice and salt crystals are calculated. Meantime, the deformation characteristic and destruction mechanism of saline soil are investigated considering the influence of the crystallisation and dissolution of ice and salt crystals, and the thermal expansion coefficient discrepancies between pore fluids and solid matrix. Finally, from the test results, it is found that salt concentration, fusion energy and ambient liquid pressure played important roles on ice pressure, and salt concentration had influence on salt crystallisation pressure. And, a computing method of ice pressure considering the influence of salt concentration, fusion energy and ambient liquid pressure, is proposed.