Abstract:

Consolidated drained and consolidated undrained triaxial creep tests of soft soil in Dongwan are carried out to have a comprehensive understanding of soil deformation mechanism. At the same time, scanning electron microscope test of the microstructure of undisturbed samples and samples after creep is done to analyze the soft soil creep properties and changes of micropre under different drainage conditions. The results show that different drainage conditions have a significant impact on the relationship between strain-time and strain-deviatoric stress of soil samples. Soil samples yield in undrained conditions showing significant creep deformation and do not yield in drained conditions very significantly because consolidation effect in the process of drained conditions weakens its nonlinear creep. Large pores decrease and small pores increase in soil samples after creep the shape of which is developed to be rounded and the orientation of which increase slightly. The changes of soil micropore in different drainage conditions can be taken as the internal reason of difference of soil creep. The gradual changing process of pore characteristics reveals micromechanism of soft soil creep deformation.

Key words: soft soil, drainage condition, triaxial creep, scanning electron microscope (SEM), microstructure