Abstract: Based on the unconfined compressive strength of cemented soil and lime-cement soil that are analyzed by tenacity method, the study of the curing mechanism of lime-cement soil is carried out. In the aspect of unconfined compressive strength, the experiment of cemented soil specimens and lime-cement soil specimens which are made according to the ratio of cemented soil and lime-cement soil, has been completed after 28 days’ standard curing. Ca(OH)2, CaCO3,and cement were chosen as addtives with different levels to be mixed in the cemented soil and lime- cement soil. Its compressive strength is tested and the experiment result is analyzed. The research results indicate that the strength of cemented soil and lime- cement soil originates mainly from the composite binding effect and the physical filling effect in the cemented soil. The physical filling effect, pozzolanic effect and particle of clay ionic exchange and quadrate reaction, action of cement hydrate and combined action exist in lime-cement soil. The research results also indicate that the action of cement hydrate is the mian reason for the increasing rule of the strength of cemented soil and lime-cement soil; and the hydrated lime can restrict cement hydration but doesn’t stop cement hydration.

Key words: unconfined compressive strength, mechanism, tenacity method, lime-cement soil