Uplift Behavior of Screw Anchors in Sand. II: Hydrostatic and Flow Conditions

Abstract

The behavior of model single‐pitch screw anchor installed in dense sand subjected to hydrostatic pressure or upward seepage flow is presented. The experimental setup described in a companion paper was modified to allow preparation of submerged sand and to provide upward seepage flow at a constant rate. The effect of the seepage flow velocity on the effective stress of the sand as well as on the ultimate uplift resistance of the anchor was examined. The theoretical model developed in the companion paper was used to predict the uplift capacity of this type of anchor installed in submerged sand or sand subjected to upward seepage flow velocity. An equation is proposed to account for the effect of the seepage flow velocity on the angle of inclination of the failure surface. Comparison of theoretical and experimental results showed good agreement. The present theory compared well with the available field results reported in the literature.