Predicting the Maximum Axial Capacity of Secant Pile Walls Embedded in Sandy Soil

Secant pile walls (SPWs) are frequently employed as temporary excavation support systems in urban areas; thus, they are useless once permanent foundations and basements have been constructed. Recently, attempts have been made to employ these walls to bear axial loads and lateral earth pressure, which may have significant potential benefits. Unfortunately, the shortage of research that recognizes them as bearing elements, especially numerical studies, has prevented this approach from reaching the final design and implementation stage. Thus, the primary objective of this research was to calibrate a finite element model to depict the performance of axially loaded SPW and extend the finite element analysis by including key factors and additional trials that may impact the performance of the axially loaded SPW. This research investigated various aspects to describe SPW behavior, including the maximum axial capacity of the SPW (Pmax), normalized horizontal deflection (delta h/Ht%), normalized ground settlement (delta vg/Ht%), the normalized vertical deflection of the SPW (delta vw/Ht%), the normalized pivot point location (epsilon '/He) and settlement influence zone (Do). Several parameters, such as normalized penetration depth (He/Hc), sand relative density (Dr), surcharge load density (Wsur), and wall rigidity (Ht/Dp), were studied and examined in relation to these aspects. Additionally, 224 axially loaded SPW trails were performed as part of a parametric study. The findings demonstrated that the proposed FEM could depict the performance of the experimental model with fair accuracy under the effect of the axial and lateral loads. The effects of the investigated aspects on the Pmax were also discussed in detail. Also, using linear and non-linear regression analysis, the data from the parametric analysis was utilized to create rational relations between the various parameters. The best-achieved mathematical models for predicting the Pmax were also represented in graphical forms. Moreover, these graphs can be a useful and fast tool for civil and geotechnical engineers to predict the maximum axial capacity of an SPW according to the different variables.