Pullout capacity of vertical plate anchors in unsaturated clay considering variable surface flow conditions

Abstract

Vertical plate anchors are placed in the soil to improve the lateral resistance of various geotechnical structures. Extensive research has been conducted to find out the pullout capacity of vertical anchors in saturated or dry soil. Despite all these attempts, no research is available to study the behavior of anchors in unsaturated soil where the shearing resistance of soil is governed by the matric suction depending on the surface flow conditions and water table positions. Since the soil in field is mostly in unsaturated state; thus, the pullout resistance of vertical plate anchor has been aimed to be evaluated in this study. Finite element limit analysis solutions in terms of a non-dimensional pullout factor have been presented to find the pullout capacity of vertical anchors. The solutions are inclusive of the effect of soil properties, embedment depth, height of anchor plate, depth of water table from the ground surface, flow conditions and flow rate under an immediate breakaway condition. The effect of variation of other factors like the degree of saturation, unit weight of soil, van-Genuchten SWRC parameters, specific gravity of soil solids, and anchor-soil interface conditions has also been evaluated.