Microscopic analysis of saturated soft clay in Pearl River Delta

A series of researches were carried out for the soil samples in the Pearl River Delta under the action of consolidation loads, such as the quantitative analyses of the pore scale, shape and size distributions of micro-structure units, with an environmental scanning electron microscope (ESEM), a mercury intrusion analyzer and a mineral diffractometer. The experimental results show that the consolidation pressures remarkably change the pore sizes and distribution characteristics of the silt, thus changing its compressibility and permeability. This can be proved by the fact that, in the earlier stage with a consolidation pressure of p<200 kPa, the pore sizes are greater and the compressibility and permeability coefficients are larger. However, they rapidly decrease with the increase in consolidation pressure. And in the later stage with a consolidation pressure of p>200 kPa, the pore sizes are smaller and the compressibility and permeability coefficients are less. Therefore, the empirical formulas of compression coefficient and permeability coefficient vs consolidation load and average pore diameter are deduced.