Response of Anchors in Undrained Soil Under Combined Loading

In the field of onshore and offshore structures, plate anchors are widely used due to their simplicity and cost-effective installation. So, extensive attention has been devoted to understanding the behavior of plate anchors when exposed to combined loads due to their widespread use. However, most prior research has predominantly concentrated on deeply embedded horizontal anchors, leaving a gap in understanding the behavior of vertical plate anchors. Additionally, the effect of embedment depth on the response of horizontal and vertical anchors under combined loadings also needs to be investigated. To bridge this knowledge gap, this paper utilizes Finite Element (FE) analysis to explore the impact of anchor embedment and geometry on failure envelopes. A new design method considering anchor-soil interaction is proposed through validating FE results with available numerical results. Additionally, we found that in symmetrical loading planes, the shape and size of these envelopes remain unaffected by embedment depth. However, in asymmetrical loading planes, the failure envelope changes its shape from asymmetrical to symmetrical at D/B ≥ 2. Our results reveal that as the width-thickness ratio (B/t) increases from 7 to 20, the sliding capacity decreases by 36%. Moreover, transitioning from a smooth to a rough interface condition results in a remarkable 50% increase in sliding capacity. This comprehensive study significantly enhances our understanding of plate anchors' behavior and paves the way for more informed and effective structural designs in various applications.