Mechanical Properties of Black Soil Under Dry-Wet,Freeze-Thaw Cycles
To analyze the mechanical property changes of the black soil under dry-wet and freeze-thaw cycles,the fissure obser-vation,volumetric strain measurements,direct shear tests and unconfined compression tests are performed on black soil sam-ples under the two cycling modes.The results show that:(1)Black soils are characterized by the wet swelling and the dry shrinkage,the frost swelling and the melt shrinkage.After the first dry-wet cycle,the net volumetric strain is 12.5％and ob-vious cracks occur;After the first freeze-thaw cycle,the net volumetric strain is 0.45％without obvious cracks.(2)The inter-nal friction angle of black soil samples decreases the most after the first dry-wet cycle,from 25.2° to 23.7°,and is basically sta-ble after the third cycle.The internal friction angle decreases from 25.2° to 23.4° after the first freeze-thaw cycle and then fluc-tuates around 23.4°.In both cycling modes,the cohesion decreases with the increase of the number of cycles,and the decay of the cohesion is greater after the dry-wet cycles.(3)After the first dry-wet cycle,the unconfined compressive strength of the black soil samples decreases by 32.3％.After the first freeze-thaw cycle,the unconfined compressive strength deceases by 38.2％.The unconfined compressive strength of black soil samples is stabilized in the third cycle.
Black SoilDry-Wet CyclesFreeze-Thaw CyclesShear StrengthVolumetric Strain
万方数据
维普
