Abstract:To investigate the different effectiveness between dredger fill and natural soft soil in the cement-mixed improvement processes of an engineering case,two kinds of micro-experiments on dredger fill and natural soft soil before and after cement-mixed processes were carried out by using X-ray diffraction(XRD)and scanning electron microscope(SEM)tests in the view of chemical and physical microstructures.It is found that the physical microstructures have an important effect on the reinforcement performance of cement-mixed soils.Although the chemical reactions of cement-mixed processes are similar in both dredger fill and nature soft soil,there are significant differences in the microstructures of treated soils,which can affect the macro-scale strength directly.Therefore,in order to optimize the improvement in soft ground engineering,proper construction measures should be taken to improve the microstructures and mechanical properties of the dredger fill.