Effect of axial and interface shear stiffness on pullout of sheet reinforcement

Axial pullout response of inextensible and extensible reinforcement is studied using FLA C. Soil is modeled by elastic, isotropic constitutive model and reinforcement as a beam element. Interface shear stress is quantified based on the shear stiffness of unglued reinforcement-soil interface. Tension developed in the reinforcement, horizontal deformation of reinforcement and soil are presented for different pullout loads and the influence of interface shear stiffness is studied. Mobilization of interface shear stress along the reinforcement and transfer of shear stress from reinforcement to the soil surrounding is demonstrated for different pullout forces. Interface shear stress is mobilized along full length of inextensible reinforcement whereas a limited active portion of extensible reinforcement carries interface shear stress. Peak value of interface shear stress occurs at a distance away from the loaded end of reinforcement and a residual value is mobilized at the loaded end. Iterative finite difference scheme of FLAC and its continuum approach is a better tool to demonstrate the mutual transfer of stresses and displacements between reinforcement and soil through the unglued interface element.