Abstract:Researches show that the slurry with quick lime as admixture is well compatible with earthen sites, and adding the micro-lime piles into this slurry can better eliminate shrinkage differentiation phenomenon of the slurry-soil interface. In order to explore the reinforcement effect and mechanism under the synergy of pile-slurry, fissure grouting of indoor earthen sites was carried out under single grouting technology and pile-slurry synergistic reinforcement technology with the width-diameter ratio of 1.5, 2.0, 2.5 and 3.0 (ratio of crack width to lime pile diameter). After curing for 63 days, the macro-properties (penetration resistance, density, liquid plastic limits and particle composition) of equidistant soil on both sides of the fissures were tested. Then the reinforcement effects of the soil on both sides of fissure were qualitatively and quantitatively analyzed by scanning electron microscopy, the specific surface area, cation exchange capacity and pore relative change rate of soil (P_r). The results showed that the reinforcement effect was better than that of single grouting when the width-diameter ratio was less than 2.5. The effect of soil reinforcement increased first and then decreased as the width-diameter ratio increases, and was the best when width-diameter ratio equaled to 2.0, and was weaker than that of single grouting when the width-diameter ratio was more than 3.0. The essence reflected by the results was that the compaction and agglomeration of soil on both sides of fissures caused by the expansion and ion migration of lime pile and slurry were not a simple linear superposition, but when the width-diameter ratio was more than 2.0, the slurry would obviously inhibit the compaction and agglomeration of the lime pile.