Numerical and Analytical Studies of 3D Effects on Pullout Capacity of Anchor Blocks in Granular Compacted Fill

Generally, geotechnical construction works such as sheet pile walls are designed as plane-strain problems. In many practical cases, even if there is a need to consider 3D effects in the analysis, the designer tends to adopt conservative 2D analysis resulting in uneconomical design. This paper discusses a project in Dubai where sheet pile wall tie backed to anchor block was designed to retain 6.25 m height of compacted fill and account for future excavation considering 3D effect in anchor blocks. Anchor blocks were used to control the initial large deflections (> 50 mm) calculated in the sheet pile. Anchor blocks were analyzed considering 3D effects which resulted in increased pullout resistance (2.3 times) compared to assuming it as plane-strain problem. Simultaneously, numerical analyses were performed and an increase in pullout resistance (1.8 times) was noticed in 3D analysis compared to 2D analysis which confirms the importance of considering 3D effects in analyzing anchor blocks fetching subsequent optimization in anchor block design.