Evaluation of negative skin friction effects in pile foundations using 3D nonlinear analysis

Comodromos, Emilios M.; Bareka, Spyridoula V.

doi:10.1016/j.compgeo.2005.01.006

Cited by 53 publications

(32 citation statements)

References 8 publications

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“…9 shows that when surcharge load (S.L.) equals 50 kPa, the dragload distributions along pile depth are in good agreement with the results obtained by previous models (Lee et al, 2002;Comodromos and Bareka, 2005), thus verifying the correctness of the numerical model in this study.…”

Section: Comparative Analysis With Literature Numerical Modelssupporting

confidence: 91%

“…In this study, the pile and soils parameters were chosen as shown in Table 4, taking the parameters used in the literature (Lee et al, 2002;and Comodromos and Bareka, 2005). Fig.…”

Section: Comparative Analysis With Literature Numerical Modelsmentioning

confidence: 99%

“…The relationship between pore water pressures, layered soil settlement, NSF of pile shaft versus consolidation time under surcharge load were measured. Numerical simulation analyses focused on dragload of piles subjected to surcharge load were analyzed (Chow et al, 1996;Lee et al, 2002;Jeong et al, 2004;Comodromos and Bareka, 2005;Hanna and Sharif, 2006;Sun et al, 2013;Fakharian et al, 2014). Many influence factors, such as the soil slip at the interface, the pile group configuration, the relative location of the piles within the group, and the interface friction coefficient, were analyzed and discussed.…”

Section: Introductionmentioning

confidence: 99%

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Group effect of dragload in pile groups embedded in consolidating soil under embankment load

2015

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In this paper, model tests and numerical simulations on 3 × 3 pile group embedded in consolidating soil under embankment load with different pile spacings are carried out. Single pile and 2 × 2 pile group are studied for comparative analyses. The performances of dragload versus relative displacement of pile-soil, load sequence and load rate, and the group effects of dragload and downdrag versus pile spacing are analyzed. A case study on dragload of a pile group considering with or without couple effect is also presented. It is worth pointing out that in this experimental condition, when pile-soil relative displacements reach 2 mm, dragload will reaches nearly 75-95% of the maximum values; When consolidation time reaches 240 h, the neutral plane becomes stable approximately at 0.95H (H is the thickness of compression soil). The dragload and downdrag are influenced by load sequence of pile head load versus surcharge load.

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Section: Comparative Analysis With Literature Numerical Modelssupporting

confidence: 91%

“…In this study, the pile and soils parameters were chosen as shown in Table 4, taking the parameters used in the literature (Lee et al, 2002;and Comodromos and Bareka, 2005). Fig.…”

Section: Comparative Analysis With Literature Numerical Modelsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Group effect of dragload in pile groups embedded in consolidating soil under embankment load

2015

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“…Interface elements combining non-linear stiffness components with sliders and dilatant components were employed to mimic the behavior of granular media in simple shear at the interface with the pile (Comodromos and Bareka 2005). Thin elements were employed to model shaft friction and the effects of localized shear around cast-in-place piles (Lee and Long 2008;Liu et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Analysis of Friction Induced Thermo-Mechanical Stresses on a Heat Exchanger Pile in Isothermal Soil

2014

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In most analytical and numerical models of heat exchanger piles, strain incompatibilities between the soil and the pile are neglected, and axial stresses imposed by temperature changes within the pile are attributed to the thermal elongation and shortening of the pile. These models incorporate thermo-hydro-mechanical couplings in the soil and within the pile foundation, but usually neglect thermomechanical couplings between the two media. Previous studies assume that the stress changes imposed by temperature variations in a heat exchanger pile are mainly due to the constrained thermal elongation and shortening of the pile. Also, several recent approaches utilize spring models that focus only on the soil-pile interface in modeling temperature-induced stresses in a heat exchanger pile and implicitly ignore the effect of the full displacement field on soil-pile interaction. By contrast, in this paper, interface elements are introduced in a numerical model of a heat exchanger pile, analyzed in axisymmetric and stationary conditions. The pile is subjected to a uniform temperature increase, with free top and fixed top conditions in elastic and elasto-plastic soil profiles. Simulation results show that the constrained vertical elongation is the most detrimental factor for pile foundation performance. However it is worth noticing that while mechanical constraints (e.g., fixed top and/or fixed bottom) impose maximum stress increases at the ends of the pile, interface effects result in maximum stresses around the mid-length of the pile. This preliminary study indicates that soil-pile friction does not increase pile internal stresses to the point where it would be necessary to over-dimension the foundation pile for heat exchanger use. Furthermore, one cannot expect a significant gain in foundation performance due to the improvement of soil-pile frictional resistance as a result of increased lateral stresses at soil-pile contact. Additional numerical analyses are ongoing, in order to investigate the role of the degree of fixity induced by the building on the heat exchanger pile, and to extend these preliminary analyses to transient operational modes and cyclic thermo-mechanical loading of the heat exchanger pile.

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“…POULOS [4] pointed out that the group effect could influence the dragload and downdrag of pile foundations. Some studies on group effect were conducted by JEONG et al [5−6], CHOW et al [7], LEE et al [8], and COMODROMOS et al [9]. These studies were very helpful for understanding the behavior of pile group under dragload and predicting the group effect, while the studies on the group effect of pile group embedded in clay were scanty.…”

Section: Introductionmentioning

confidence: 97%

Evaluation of group effect of pile group under dragload embedded in clay

Kong

Yang

Zheng

et al. 2009

J. Cent. South Univ. Technol.

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A simple semi-empirical analysis method for predicting the group effect of pile group under dragload embedded in clay was described assuming an effective influence area around various locations of pile group. Various pile and soil parameters such as the array of pile group, spacing of the piles (S), embedment length to diameter ratio of piles (L/D) and the soil properties such as density (γ), angle of internal friction (φ) and pile-soil interface friction coefficient (µ) were considered in the analysis. Model test for dragload of pile group on viscosity soil layer under surface load consolidation conditions was studied. The variations of dragload of pile, resistance of pile tip and the layered settlement of soil with consolidation time were measured. In order to perform comparative analysis, single pile was tested in the same conditions. The predicted group effect values of pile group under dragload were then compared with model test results carried out as a part of the present investigation and also with the values reported in literatures. The predicted values were found to be in good agreement with the measured values, validating the developed analysis method. The model test results show that negative skin friction of pile shaft will reach 80%−90% of its maximum value, when pile-soil relative displacement reaches 2 mm.

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Evaluation of negative skin friction effects in pile foundations using 3D nonlinear analysis

Cited by 53 publications

References 8 publications

Group effect of dragload in pile groups embedded in consolidating soil under embankment load

Group effect of dragload in pile groups embedded in consolidating soil under embankment load

Analysis of Friction Induced Thermo-Mechanical Stresses on a Heat Exchanger Pile in Isothermal Soil

Evaluation of group effect of pile group under dragload embedded in clay

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