Modified axial pullout resistance factors of geogrids embedded in pond ash

Abstract

Abstract In the internal stability design of reinforced soil structures, the existing design provisions consider only axial pullout of the reinforcement. However, the kinematics of deformation clearly shows the reinforcement to be subjected to an oblique pull along the failure surface. The overall response due to oblique pull of reinforcement can be considered as cumulative individual responses of axial and transverse components of oblique pull. In the present work, the transverse pullout responses of four geogrids embedded in pond ash under three different normal stresses were studied. Geogrids considered varied in geometric and mechanical properties of the grids to study the effects of their tensile stiffnesses/strengths and opening sizes on transverse pull-displacement response. Based on extensive laboratory testing, transverse pullout resistance factors ( F t ∗ ) were proposed; additionally, empirical equations were proposed to estimate the transverse pullout resistances of geogrids in pond ash. F t ∗ of the four geogrids in pond ash ranged between 0.08-0.31 and 0.21–0.99\xa0at front-end transverse pullout displacements of 20\xa0mm and 35\xa0mm, respectively. Finally, sensitivity analysis was conducted to identify the parameters significantly influencing the transverse pullout resistance of geogrids. The effect of grid opening size on transverse pull of geogrid was observed to be minimal; while the tensile strength showed a significant effect.