Microstructural Change of Clay under Compression

Abstract

Triaxial test and SEM test are combined to investigate the microstructural variation of Zhejiang marine clay during compression. SEM images are processed and analysed quantitatively, employing an improved determination for threshold. Then the concept of critical threshold is proposed. The test results show that: during compression, it was the pores with middle and large size which were mainly compressed. 2D porosity and fractal dimension showed a decreasing trend, indicating that pore morphology tended to be uniform. A linear relationship between 2D porosity and real porosity can be observed. Similarly, a positive correlation was established between real porosity and fractal dimension. No obvious orientation was found for both clay particles and pores. Finally, the ellipticity distribution of clay particles were stable and concentrated in the interval of 0.4~0.6. some of the macroscopic properties, such as isotropy and internal friction angle, can be a reflection of these variations in microstructure.