Settlement analysis of rectangular piles in nonhomogeneous soil using a Winkler model approach

To investigate the settlement response, load transfer behavior, and geometric effect of noncircular piles, a general three‐dimensional (3D) analytical continuum model for axially loaded noncircular pile‐multilayered homogeneous soil systems is presented. In the analysis, both the vertical and horizontal soil displacement fields are considered, and the variations of the soil displacement components are described by the three displacement transfer functions along the x, y, and z directions. The governing differential equations of noncircular piles and soil are derived by applying the principle minimum potential energy and variational method to the pile‐soil system. A complex variable function conformal mapping technique is introduced to overcome the complex boundary conditions of the transfer functions. Then, the numerical solutions of all the governing differential equations are simultaneously solved following an iterative algorithm. The reliability of this approach is validated by comparing some pile and soil responses with the results from existing analytical solutions or a rigorous finite element analysis. Differences in the settlement response and the axial force distribution between noncircular and circular piles are observed. In addition, the pile shaft resistance along the perimeter of the cross‐sections shows that a greater load is required in order to fully mobilize the ultimate resistance of the noncircular piles. We also compare the stress (σ1−σ3) contours of some typical noncircular piles with a circular pile, which provides useful insights into the geometric effect.

Section: Introductionmentioning

confidence: 99%

Three‐dimensional analytical continuum model for axially loaded noncircular piles in multilayered elastic soil

Zhou

Liu

et al. 2021

“…The behavior of single pile and pile groups subjected to lateral loading has been studied in details under static loading conditions using analytical approaches. Studies on vertically and laterally loaded piles embedded in nonhomogenous and layered soil using a Winkler model approach were studied by Basu and Salgado, Guo, and Hirai . Nevertheless, these methodologies did not take into account the presence of kinematic forces and depth of liquefiable soil layer and their influence on the bending moment generated in the pile and the unsupported pile length leading to instability.…”

Section: Introductionmentioning

confidence: 99%

Influence of seismic motions on behavior of piles in liquefied soils

Chatterjee

Choudhury

2017

Summary In the present study an analytical procedure based on finite element technique is proposed to investigate the influence of vertical load on deflection and bending moment of a laterally loaded pile embedded in liquefiable soil, subjected to permanent ground displacement. The degradation of subgrade modulus due to soil liquefaction and effect of nonlinearity are also considered. A free headed vertical concrete elastic nonyielding pile with a floating tip subjected to vertical compressive loading, lateral load, and permanent ground displacement due to earthquake motions, in liquefiable soil underlain by nonliquefiable stratum, is considered. The input seismic motions, having varying range of ground motion parameters, considered here include 1989 Loma Gilroy, 1995 Kobe, 2001 Bhuj, and 2011 Sikkim motions. It is calculated that maximum bending moment occurred at the interface of liquefiable and nonliquefiable soil layers and when thickness of liquefiable soil layer is around 60% of total pile length. Maximum bending moment of 1210 kNm and pile head deflection of 110 cm is observed because of 1995 Kobe motion, while 2001 Bhuj and 2011 Sikkim motions amplify the pile head deflection by 14.2 and 14.4 times and bending moment approximately by 4 times, when compared to nonliquefiable soil. Further, the presence of inertial load at the pile head increases bending moment and deflection by approximately 52% when subjected to 1995 Kobe motion. Thus, it is necessary to have a proper assessment of both kinematic and inertial interactions due to free field seismic motions and vertical loads for evaluating pile response in liquefiable soil.

“…Mylonakis investigated analytically the modulus of subgrade reaction based on the Winkler model for axially loaded piles. For each pile with circular and rectangular cross sections in nonhomogeneous soils, Hirai presented analytical approaches based on the elastic continuum analysis using a Winkler model, which is assumed through the modulus of subgrade reaction for the relationship between the shear stress and settlement for the vertical loading. For analysis of piled rafts subjected to vertical loads, approximate approaches have been presented by Clancy and Randolph , Poulos , Randolph , Clancy and Randolph , and Russo .…”

Section: Introductionmentioning

confidence: 99%

Analysis of piled raft with nodular pile subjected to vertical load using a Winkler model approach

Hirai

2016

Self Cite

Summary An investigation is made to present analytical solutions provided by a Winkler model approach for analysis of piled rafts with nodular pile subjected to vertical loads in nonhomogeneous soils. The vertical stiffness coefficient along a piled raft with the nodular pile in nonhomogeneous soils is derived from the displacement given by the Mindlin solution for elastic continuum analysis. The vertical stiffness coefficients for the bases of the raft and the nodular part in the nodular pile in a soil are expressed by the Muki solution for the 3‐D elastic analysis. The relationship between settlement and vertical load on the pile base is presented considering the Mindlin solution and the equivalent thickness in the equivalent elastic method. The interaction factor between the shaft of the nodular pile and the soil is expressed taking into account the Mindlin solution and the equivalent elastic modulus. The relationship between settlement and vertical load for a piled raft with the nodular pile in nonhomogeneous soils is obtained by using the recurrence equation of influence factors of the pile for each layer. The percentage of each load carried by both nodular pile and raft subjected to vertical load is represented through the vertical influence factors proposed here. Comparison of the results calculated by the present method for piled rafts with nodular piles in nonhomogeneous soils has shown good agreement with those obtained from the finite element method and a field test. Copyright © 2016 John Wiley & Sons, Ltd.