Mechanical mechanism analysis of post-penetration grouting at soil-rock interface combined with digital image technology

Aiming at the weakening of the soil-rock interface, a permeable polymer is developed in this paper, which is analyzed by combining DIC and SEM techniques. The mechanism of mechanical properties of soil-rock interface strengthened by post-osmotic grouting was studied. Through direct shear test and DIC technology, the effects of different normal pressure, water content, interface dry-wet characteristics, and curing environment on mechanical properties of the soil-rock interface were analyzed. SEM and MIP tests were used to investigate the microstructure mechanism of the soil-rock interface reinforced by infiltration grouting. The results show that the permeable polymer can improve the shear strength of the soil-stone interface mainly by enhancing the cohesive strength of the interface. The normal pressure increases the interface friction, but the interface friction coefficient decreases with the increase of the normal pressure. The water content affects the grouting effect of the polymer, and the interfacial wetting property prevents the polymer from penetrating into the interfacial direction, thus reducing the bonding strength of the interfacial. Because of the permeability of permeable polymers, the effect of the water bubble curing environment on the shear properties of the interface is less than that of the interface wetting and drying properties. SEM and MIP tests verify that the polymer effectively fills the pores in the soil and reduces the average pore size of the soil.