Abstract: Direct shear test and unconfined compression test were conducted on soft soil at Nansha of Guangzhou blended with ordinary Portland cement and admixtures such as lime, gypsum and bentonite respectively to study its mechanical property and get the variation of reinforced soils internal friction angle(IFA), cohesion, unconfined compressive strength(UCS) according to the different mixing ratios or ages of the curing agents.Scanning electron microscope observation(SEM) was also applied to research the different microstructural characteristics of different reinforced soil. The results show that data trending is similar to the outcome when cement is blended in merely. Mechanical parameters of the reinforced silt increase when the mixing ratio or age increases. But different curing agents have different influences. Lime has the best effect on longterm strength. For early age strength, bentonite has the best reinforcement effect and gypsum takes second place. To get a certain strength, both gypsum and bentonite can reduce the consumption of cement at a certain degree. The research result has a certain reference to the similar research and engineering.

Key words: curing agent； mixing ratio； curing age； mechanics experiment； electron microscope scanning