Abstract: The adhesion property of slurry-soil interface is the key issue of fissure reinforcement and earthen sites repair, and the shear strength is a key index to evaluate the adhesion property of the interface. In order to investigate the influence of SH-(CaO+F+C) slurry, interface roughness and number of lime piles on the adhesion property of slurry-soil interface in the fissure grouting system of earthen sites, the wave velocity and shear behavior of slurry-soil interface (interface failure mode, shear stress-strain curve and ultimate shear strength) with different ages and grouting modes are analyzed by indoor direct shear tests. The results show that shear strength of the interface formed by four grouting modes increase with the increase of ages, and reach stable by 63 days under the influence of the mixed slurry combined of quick lime, fly ash and modified polyvinyl. The main failure mode of the interface among all ages is the bonding failure; in addition, the thickness of the residual soil on the surface, the peak shear stress and the equivalent shear coefficient of different reinforced interfaces can be arranged in a descending order as follows: grouting with lime piles and grooves, grouting with grooves, grouting with lime piles and grouting alone. The above phenomenon are caused by different combinations of infiltration, expansion and compaction, heating, mechanical occlusion and ion migration mechanisms.

Key words: earthen sites, interface of slurry-soil, adhesion property, consolidation mechanism