吹填软土蠕变过程中颗粒与孔隙演化特征分析

软土一般具有蠕变特性，蠕变在微观上表现为土颗粒与孔隙的变化。为了解长期变形内在机制，对天津滨海吹填软土原状土与重塑土进行了固结不排水三轴蠕变试验。在围压为75 kPa、偏应力为10 kPa情况下开展多组平行试验，选取蠕变过程中多个时间点的试样进行微观结构测试，提取了颗粒与孔隙变化参数，研究蠕变过程中微结构变化规律。研究结果表明：在文中所受荷载条件长期作用下，颗粒与孔隙定向性明显；平均孔径及平均孔隙体积呈逐渐减小趋势；结构性原状土比表面积逐渐增大，重塑土则呈减小趋势；结构性原状土颗粒与孔隙分数维呈减小趋势，但重塑土呈相反趋势。

Analysis of evolution of particles and pores in creep process of dredger fill soft soil

Soft soil generally has creep characteristics, the creep on microstructure shows the changes of soil particles and pores. In order to understand internal mechanism of the long-term deformation, a consolidated undrained triaxial creep test about undisturbed and remolded of the Tianjin Binhai dredger fill is carried out. At the same time, multi-group parallel tests under the confining pressure of 75 kPa and deviatoric stress of 10 kPa are also carried out. Through selected samples of different times in the process of creep to take microstructure test, the changed parameters of particles and pores are extracted to study the variation characteristics of microstructure in the process of creep. The results show that orientation of particles and pores is significant under the long-term loading conditions; the average pore diameter and average pore volume are gradually decreased; the specific surface area of structural undisturbed soil gradually increases; but the remolded soil is in the opposite trend; structural undisturbed soil particles and pore fractal dimension are decreasing, but the remolded soil shows the opposite trend.