不同排水条件下软土蠕变特性与微观孔隙变化

对东莞软土进行了固结排水与固结不排水三轴蠕变试验、原状样与蠕变后试样水平测面微结构的扫描电镜试验，分析了不同排水条件的软土蠕变特性与微观孔隙变化规律。结果表明，不同排水条件对试样应变-时间、应变-偏应力关系产生较大影响，土样在不排水条件下屈服破坏，蠕变变形明显；在排水条件下则未有明显屈服，排水过程中的固结效应使其蠕变非线性弱化。蠕变后土样可见大孔隙减少、小孔隙数量增加、形状趋向圆状发展、定向性略有增加，不同排水条件下微观孔隙变化是土体蠕变表现差异的微观内因，孔隙特征的渐变过程揭示了软土蠕变变形的微观机制。

Creep properties and micropore changes of soft soil under different drainage conditions

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.