Numerical Modelling of Passively Loaded Pile Groups

Abstract

Piled foundations could be affected negatively as a result of passive loadings caused by nearby soil movement-induced activities, and failure of piles could happen in some sever cases. This paper deals with the numerical analysis of passively loaded pile groups and piled raft in sand. The complexity involved in such problems due to pile-soil, pile-pile, pile-cap, soil-cap, and moving soil-stable soil interaction needs a powerful tool to make three dimensional analysis possible. In the current study, PLAXIS 3D software was used to back analyse laboratory tests carried out by the authors. ''Embedded pile'' feature in which the pile is represented by beam elements, while soil-pile interaction along the pile shaft and at the pile tip is described by special interface elements was employed. The Mohr-Coulomb elastic-plastic constitutive model was used to describe the sand behaviour. Although an overestimation of the predicted deflection was obtained, the general trend of bending moment profiles of piles was in a reasonable agreement with those obtained experimentally. A number of limitations were identified as possible reasons behind the overestimation of the predicted deflections. Furthermore, parametric studies are adopted to consider the effects of pile diameter, pile-soil stiffness and pile group configuration on the response of passively loaded pile groups.

Evaluation of Soil–Structure Interaction in Structure Models via Shaking Table Test

“…The bending moment that occurs at each depth is dependent on the pile condition [29]. In the case of a fixed long pile head, the bending moment converges to zero at the tip of the pile and changes in direction at the top and bottom of the pile [20]. Therefore, in our tests, the strain gauges of the pile were attached as shown in Figure 3 to determine the magnitudes of the bending moment and the location of bending moment at which the direction of the moment changed.…”

“…Hokmadadi et al (2014) assessed the validity of the numerical analysis approach by comparing the results obtained from model shaking table testing and numerical analysis [19]. Ihsan and Tahsin (2019) compared the results of experimental and numerical analysis of piles subjected to passive loading and revealed that the numerical results overestimated deflection but produced reasonably consistent bending moments [20]. Although more accurate p-y curves based on studies of soil-structure interaction (SSI) under dynamic load conditions have been proposed, such studies have assumed that the superstructure is an SDOF structure [4,10,21].…”

Field investigation of steel pipe pile under lateral loading in extensively soft soil

“…Several studies have been conducted to evaluate the lateral response of the pile adjacent to surcharge loading, such as laboratory tests (Al-abboodi et al, 2020;Toma Sabbagh et al, 2020), finite element method (Xu and Poulos, 2001;Karim, 2013;Al-abboodi and Sabbagh, 2019), and theoretical approach (Springman, 1989;Zhang et al, 2020a;Bellezza, 2020;Zhang et al, 2020b). The laboratory tests, numerical method, and theoretical analysis (Chen and Poulos, 1997;Ellis and Springman, 2001;Abo-Youssef et al, 2021;Ramalakshmi, 2021) proved that the effect of movement soil would lead to large deformation or even failure of the pile.…”

Parametric study of passive piles subjected to adjacent surcharge load in extensively deep soft soil

“…Zhang et al (2020b) proposed a load transfer model for analyzing the pile-soil interaction and provided a semi-analytical solution. Al-abboodi and Sabbagh (2019) used Plaxis3D to investigate the group piles under soil movement in sand layers and identified a discrepancy between the predicted and test results. However, the study did not properly consider the relative lateral displacement between pile and soil and the density variation of sand.…”