Abstract:

In order to research the salt expansion laws and moving patterns of water and solute migration after several freezing and thawing cycles, the crude coarse grain saline soil samples taken from China’s Gansu province were selected for experiment of freezing and thawing cycles. In addition, the effects of the microstructure of crude saline soil after the testing of freezing and thawing cycles was researched by using SEM. It is shown that salt expansion value of crude coarse grain saline soil is accumulated before the seventh freezing and thawing cycles; but soil body could be dented in the process of cooling; and collapsibility value is accumulated with increasing cycles; and one-dimensional soil column exhibits thermal sieve effect from the top to the lower; the moving patterns of moisture content and different ion content in soil column are different under many freezing-thawing cycles.

Key words: road engineering, salt expansion, crude saline soil, freezing and thawing cycles, SEM