Influence of Relative Pile-Soil Stiffness and Load Eccentricity on Single Pile Response in Sand Under Lateral Cyclic Loading

Abstract

The environment prevalent in ocean necessitates the piles supporting offshore structures to be designed against lateral cyclic loading initiated by wave action, which induces deterioration in the strength and stiffness of the pile-soil system introducing progressive reduction in the bearing capacity associated with increased settlement of the pile foundation. A thorough and detailed review of literature indicates that significant works have already been carried out in the relevant field of investigation. It is a well established phenomenon that the variation of relative pile-soil stiffness (K rs ) and load eccentricity (e/D) significantly affect the response of piles subjected to lateral static load. However, the influence of lateral cyclic load on axial response of single pile in sand, more specifically the effect of K rs and e/D on the cyclic behavior, is yet to be investigated. The present work has aimed to bridge up this gap. To carry out numerical analysis (boundary element method), the conventional elastic approach has been used as a guideline with relevant modifications. The model developed has been validated by comparing with available experimental (laboratory model and field tests) results, which indicate the accuracy of the solutions formulated. Thereafter, the methodology is applied successfully to selected parametric studies for understanding the magnitude and pattern of degradation of axial pile capacity induced due to lateral cyclic loading, as well as the influence of K rs and e/D on such degradation.

Energy-Based Approach: Analysis of a Vertically Loaded Pile in Multi-Layered Non-Linear Soil Strata

“…The pile deflection equation can be solved when the soil and geometry related parameters k, C and m are known; however, these parameters depend on the unknown dimensionless soil function φ, which can be estimated by calculating γ 1 and γ 2 . Soil displacement is obtained when the initial numbers of these values γ 1 and γ 2 , are inserted into Equation (19), from which the parameters k, C and m are obtained as a result of the pile displacement. New values of γ 1 and γ 2 (Equations ( 20) and ( 21)) are determined and then inserted into Equation (19) to evaluate φ then v; therefore, an iteration technique is needed to obtain the condition γ old −γ new γ old < 0.001.…”

“…Several researchers estimated the pile deformations based on the energy-based method [1][2][3][4][5][6][7]. There are many numerical methods available in the published literature with various pile geometry and constitutive models using the Finite Element Method (FEM) [8][9][10][11][12][13], the Finite Difference Method (FDM) [8,[14][15][16][17][18] and the Boundary Element Method (BEM) [3,4,[19][20][21][22]. The present study is based on the FDM since it yields results faster when compared to the FEM.…”

Analysis and Design of Monopile Foundations for Offshore Wind-Turbine Structures

“…Details on these topics can be found in Basack and Dey (2012), Sen (2014), Guo (2006), Guo (2013) and Rani and Prashant (2014).…”

Piles Subjected to Torsional Cyclic Load: Numerical Analysis

“…The primary reason for such degradation is the gradual reorientation and rearrangement of the soil particles adjacent to the pile-soil interface. The other reasons include the generation of excess pore water pressure and the development of irrecoverable plastic deformation of soil adjacent to the pile soil interface (Basack and Dey, 2012).…”

“…These include the dynamic response analysis, cyclic stability analysis, finite element and boundary element analysis etc. to name a few (Poulos, 1982(Poulos, , 1988Bea, 1992;Basack and Dey, 2012;Fatahi et al, 2014). In the present paper, a novel numerical methodology based on boundary element modeling (BEM) is proposed to capture the response of a single, vertical, floating pile subjected to combined axial, and torsional cyclic loads.…”