Mobilised Frictional Shear and Dead-Weight of Sand Wedge: Contributing to the Pull-Out Resistance of Belled Anchor Pile in Sand

Abstract

This study explains the pull-out resistance of belled anchor pile under vertical tension, by using 1-g panel of belled anchor pile (2D) possessing embedment ratios (L/Wb) of 3–5, thickness ratios (Ws/Wb) of 0.28–0.46 and bell angles (α) of 45°–72° in dyed and non-dyed homogeneous dry sand deposit. Under vertical pull, the applied stresses are acting along the vertical plane of the panel, and so symmetrical nonlinear slip surfaces are formed in both the sides of each panel. To predict pull-out resistances, the slip surfaces are interpreted as 3D axisymmetric failure wedges surrounding the anchor models of same scale. The predicted pull-out resistance of each model is the combination of mobilised frictional shear and dead-weight of sand wedge. The values of pull-out resistance are within the range of 22.88–383.70 N. The pull-out resistances are increased with higher L/Db, lesser Ds/Db and α of anchor models based on variation in the horizontal extent of failure points in slip surfaces. The ratios of mobilised frictional shear to pull-out resistance (× 100, %) of anchors are within the range of 13.50 to 30.81%, and these values are decreased due to higher L/Db and increased due to higher Ds/Db and α. The ratios of dead-weight of sand wedge to pull-out resistance of anchors (× 100, %) are within the range of 69.20–86.50%, and these values are increased due to higher L/Db and decreased due to higher Ds/Db and α.