STRENGTH EVOLUTION AND MICRO-STRUCTURE MECHANICS OF STRUCTURED SOFT DREDGER FILL FROM TRIAXIAL CREEP TEST

The long-term deformation of structural soils inevitably affects soil structure. Through triaxial creep test for structural soft dredger fill, the micro-mechanics and the changes of structure strength were studied by choosing representative sample during the creep. The results show that the essence of creep is the process about mutual transformation between hardening and softening of the internal structure of soil. When the stress level is less than the structure yield stress, the hardening accounts for the main portion in the process of creep, and the change of micro-structure is gradually stabilized, the structure strength increases accordingly. The softening accounts for the main portion in the process of creep when the stress level exceeds the structure yield stress. This stage can be subdivided into two stages. They are the heavy soil structure destruction stage and the soil ultimate failure stage. The micro-structure is changed from the stable stage to the unstable stage, eventually back to the disorder stage.