THE LOADED SWELLING RATIO TEST AND MODEL PREDICTION OF WEATHERED SAND IMPROVED EXPANSIVE SOIL UNDER FREEZE-THAW CYCLES

This paper researched the qualitative and quantitative relationships among loaded swelling ratio of weathered sand improved expansive soil，weathered sand content and cycles of freeze-thaw tests by adding respectively 0， 10%， 20%， 30%， 40% and 50% of the weathered sand into the expansive soil. The loaded swelling ratio test under 25 kPa and 50 kPa was done with leveraged consolidation apparatus after 0，1，3，6，9，and 12 cycles of freezing and thawing. Test results showed that with the increasing of cycles of freeze-thaw，the loaded swelling ratio of weathered sand improved expansive soil decreased with different change magnitude under the same sand ratio. With the increasing of weathered sand proportion，the loaded swelling ratio first increased and then decreased under the same freeze-thaw cycles. When the content of sand was 10%，the loaded swelling ratio reached the maximum. The relationship between the loaded swelling ratio of weathered sand improved expansive soil and freeze-thaw cycles expressed a logarithmic function in the same sand ratio under the action of 25 kPa overlying load，and linear function under 50 kPa .