Experimental study on the deformation of sandy soil around multi-helical anchor piles under horizontal load

Abstract

The deformation characteristics of sandy soil around multi-helical anchor piles have an important influence on their bearing capacity under horizontal loading. To explore the interaction mechanism between anchor pile and soil, this study combines a model test system with particle imaging velocimetry to study the deformation and bearing characteristics of the soil around multi-helical anchor piles under horizontal loading. The results show the following. (1) The sand density and anchor sheet buried depth have a significant effect on the range of the influence of the soil displacement around the helical anchor pile, and on the distribution of the active and passive zones. (2) With increasing density, the influence area of the active zone rearward of the pile decreases, whereas the opposite is true for the passive zone in front of the pile. Under shallow buried conditions, the area of influence of the passive zone rearward of the pile extends to the sand surface; whereas under deep buried conditions, the area of influence of the transition zone decreases. (3) The buried depth is the main factor in the formation of the transition zone and the rotating damage zone. As the buried depth increases, the angle between the shear failure surface of the passive zone rearward of the pile and the vertical direction gradually decreases; the development direction of the shear failure surface of the disturbance zone in front of the pile is lower right-vertical downward-lower left. (4) The volume expansion zone on the left side of the helical anchor pile gradually transitions from extending to the surface of the sand to the lower left side of the bottom anchor. Regardless of the buried depth, the maximum value of the volume strain in the soil always occurs in the upper part of the top anchor, and the soil between the two anchor plates is always in the volume contraction zone.