Abstract: With the typical saturated sandy gravel stratum in Beijing as the research object, the frost heave and thawing characteristics of saturated sandy gravel under different fine soil contents and load conditions are studied. The results show that there is a significant shrinkage phase at the initial stage of freezing of saturated sandy gravel specimens under loading conditions, and the shrinkage is 0.053% of the specimen height. Both the frost heave ratio and the thawing settlement coefficient have an obvious exponential correlation with time. Under the same condition of fine soil content, the thawing settlement coefficient of saturated sandy gravel (the content of fine soil is greater than 10%) and the frost heave ratio decrease with the increase of load, and the load has little effect on the thawing settlement coefficient of saturated sandy gravel with a fine soil content less than 10%. Under the same load condition, the frost heave ratio and thawing settlement coefficient of saturated sandy gravel increase with the increase of fine soil content. Load has the greatest influence on the frost heave rate, followed by the fine soil content. Unloaded saturated sandy gravel with a fine soil content less than 0.82% is a weak frost heave material. A prediction model for the frost heave ratio and thawing settlement coefficient of saturated sandy gravel considering the influence of fine soil content and load is established.

Key words: saturated sandy gravel, fine soil content, load, frost heave ratio, thawing settlement coefficient