Disintegration characteristics of collapsible loess after vibration compaction

Abstract

The main objective of this study is to evaluate the disintegration characteristics of loess after treatment by vibratory probe compaction method. To establish the connection between the disintegration velocity of loess soil and other parameters, a series of indoor and in situ tests was conducted, including density test, compression test, direct shear test, collapsibility test, standard penetration test (SPT) and cone penetration test. The results showed that a great improvement of the resistance of loess samples to wetting and disintegration was obtained after treatment, and its disintegration velocity (0.2%/s) had a larger reduction of 75.85% compared to the value before treatment. The disintegration velocity had a positive linear correlation with the void ratio, collapsibility coefficient and self-weight collapse coefficient, but a negative linear correlation with the dry density and modulus of compressibility. From in situ test results, the disintegration velocity showed a negative correlation with the SPT blows, and the cone resistance and sleeve friction of the soil layer at different depths corresponded well to the disintegration velocity. The vibratory probe compaction method is an effective way to eliminate collapsibility and improve the allowable stress for collapsible loess foundation; it can also minimise the disintegration threat of loess in water to engineering construction.