Study of Stress-Strain State of foundation structures in determining pile vertical stiffness if various software suites

Summary This paper presents the results of numerical modeling of the interaction between a sheet pile retaining wall and the soil foundation using the Plaxis software package. A detailed analysis of the stress-strain state (SSS) of the retaining wall was carried out for both two-dimensional (2D) and three-dimensional (3D) problem formulations. The aim of the study is to evaluate the influence of the spatial modeling approach on the distribution of forces and displacements in the retaining wall structure and to compare the results of 2D and 3D analyses. As part of the study, the 2D calculation of the SSS of the retaining wall was performed using the Plaxis 2D software. This method provides the distribution of stresses and strains within the cross-sectional plane of the structure, offering valuable insights into the interaction between the wall and the soil foundation. However, the main limitation of this approach is its inability to account for the spatial behavior of structures, including the interaction between different structural elements such as piles, walers, and bracing components. The 3D analysis was performed using the Plaxis 3D software, employing the Hardening Soil model for soil behavior. This approach enables a comprehensive consideration of the spatial behavior of structures, allowing for a more accurate simulation of the retaining wall's performance under load. The model takes into account the influence of walers and bracing components, ensuring a more uniform force distribution within the structure. Three characteristic piles were selected for analysis: a corner pile (№1), an edge pile (№2), and a central pile (№3). The results of numerical modeling revealed that the bending moments and horizontal displacements for the corner and edge piles exhibit similar patterns and close values in both the 2D and 3D analyses. However, significant differences in the distribution of bending moments and displacements were observed for the central pile. This discrepancy is attributed to the inclusion of additional structural elements in the 3D model, which distribute the loads more evenly and improve result accuracy. The findings confirm the importance of using 3D modeling for the assessment of the stress-strain state of complex engineering structures such as sheet pile retaining walls. They also demonstrate that accounting for the spatial behavior of structures significantly affects the final distribution of forces and displacements, providing a more precise representation of the wall's real behavior.