Abstract: To investigate the variation of the pore size distribution of soft soil under the external loading, one-dimensional consolidation tests on Zhanjiang soft soil samples under vertical pressure of 100~800 kPa were performed. The pore size distribution of soil samples under different loads was characterized by the mercury intrusion method, and the pore structure was further analyzed by the uniformity and typing characteristics. The results show that the pore size r=0.25 μm can be regarded as the critical pore size of the tested soft soil, which divides the soil pore into compressible pore sizes (r≥0.25 μm) and incompressible pore sizes (r<0.25 μm). As the load increases, the compressible pore size decreases linearly, and the incompressible pore size remains almost unchanged. The larger the external load, the better the uniformity of the pore size distribution, and the uniformity coefficient C of the pores increases, that is, the pore size distribution tends to concentrate from complexity. The pore size structures experiencing different external loads have good fractal characteristics, and the fractal dimension is between 2.98 and 2.94, and decreases with increasing of external load.

Key words: Consolidation, Mercury Intrusion Test, Porous Structure, Uniformity, Fractal Dimension