Abstract: The hyperbolic model was introduced to describe the relationship between the friction shear stress and the relative shear displacement at the interface between the soil nail and its surrounding soils. Based on the assumpution that the poll-out resistance of the nail follows the Mohr-Coulomb criterion and considering the soil dilatancy effects, the differential equation of dislpacement was derived and its numerical solution was obtained by using the finite difference method. Then the pull-out process was simulated. The results of the proposed model are in good agreement with results of pullout tests, which illustrated that the dilatancy of the soil-nail interface should be taken into account of estimating its pull-out bearing capacity.

Key words: foundation engineering, soil nail, glass fiber reinforced polymer(GFRP), pull-out, dilatancy, simulation, finite difference