CHANGE LAW AND PREDICTION MODEL FOR ACCUMULATIVE DEFORMATION OF ARTIFICIAL STRUCTURED SOFT SOIL UNDER LONG-TERM CYCLIC LOADING

This paper addresses the long-term settlement of embankment induced by the traffic loading and soil structure of natural soft clay. The artificial structured soils with different bonding strength are prepared. A series of compression test and dynamic triaxial tests are carried out to investigate the effects of cycle number, dynamic stress ratio and structured strength on the accumulative deformation behavior. The results indicate that accumulative deformation increases with the increase of cycle number and dynamic stress ratio, and decreases with the increase of structured strength. Three curve categories can be distinguished to describe relationships between accumulative plastic strain and cycle number. They are destructive, stable and critical types. Considering the impact of soil structure, a structured parameter called stress sensitivity S_σ is introduced into existing accumulated deformation prediction model. Then destructive and stable empirical formulas are established. They can better predict various accumulative strain curves of structured soft soils with different deformation conditions. The variation of model parameters with the stress level and structure strength is also analyzed.