Abstract: Saline soil is widely distributed in the seasonal frozen soil area of Northwest China, which has poor continuity in spatial distribution and extremely unstable engineering properties. Moreover, the mechanical properties of shallow saline soil are in dynamic changes for a long time due to the repeated influence of freezing and thawing, which brings great challenges to engineering design and construction. In view of this, through the consolidation compression test and the unconfined compressive strength test, the improvement effect of rice husk ash on chloride saline soil was studied. The results show that rice husk ash can significantly improve the compressive properties of saline soil and increase its unconfined compressive strength, and there is a negative linear relationship between the compression coefficient and compressive strength of improved soil. With the increase of rice husk ash and curing age, the compression coefficient of the improved saline soil continues to decrease, and the unconfined compressive strength shows an increasing trend, which can be increased by about 4 times. By using the loss rate of unconfined compressive strength as evaluation criteria, the frost resistance of the improved soil was evaluated. It was found that the frost resistance of the improved soil increase first and then decrease with the increase of the amount of ash, and the frost resistance effectis the most significant when the amount of ash was 15%. Relatively speaking, the curing age has little effect on the frost resistance of the improved saline soil.

Key words: saline soil, rice husk ash, consolidation compression test, unconfined compressive strength test, frost resistance