中文摘要：

采用电镜扫描仪（SEM）对在复杂应力路径作用下剪切前后的黏土样进行微观观察，并从剪切前后孔隙排列、孔隙形态、孔隙尺度变化特征3方面分析宏观试验原状软黏土归一化抗剪强度各向异性的微观本质。试验表明：剪切前后孔隙排列无序，孔隙排列方向变化很小，对黏土宏观性质影响很小；当中主应力参数b=0时，剪切过程中孔隙形态的变化对剪切后黏土归一化抗剪强度表现出的各向异性贡献较大；当b=0．5时，剪切过程中孔隙尺度的变化对剪切后黏土归一化抗剪强度表现出的各向异性贡献较大。因此，当中主应力参数不同时，影响剪切后黏土归一化抗剪强度各向异性的土的微观变化因素不同。

英文摘要：

Scanning electron microscope （SEM） was used to observe microstructure of soft clay before and after shearing under complex stress path, which analyzed microscopic nature on anisotropy of normalized shear strength of intact soft clay in three respects including changing characteristics of pore arrangement, changing characteristics of pore pattern and changing characteristics of pore scale, Test results revealed that the pore arrangement was disorder before and after shearing, and changes of pore orientation were very small, which influenced very little on macroscopic properties of clay. Changing characteristics of pore pattern contributed significantly to anisotropy of normalized shear strength of clay in coefficient of intermediate principal stress equal to 0. Changing characteristics of pore scale contributed significantly to anisotropy of normalized shear strength of clay in coefficient of intermediate principal stress equal to 0.5. Therefore, the micro-change factors which influenced anisotropy of normalized shear strength of clay after shearing were different in different coefficients of intermediate principal stress.