Numerical simulation of improvement of a liquefiable soil layer using stone column and pile-pinning techniques

Asgari, A.; Oliaei, Mohammad; Bagheri, Mohsen

doi:10.1016/j.soildyn.2013.04.006

Cited by 78 publications

(16 citation statements)

References 33 publications

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“…A unit cell-modeling approach was used similar to Asgari et al (2013), Elgamal et al (2009), Olgun and Martin (2008), and Rayamajhi et al (2014). The area replacement ratio (A r ), which is the area of the granular column divided by the total unit cell area, is varied by adjusting either the diameter or center-to-center spacing of the granular columns.…”

Section: Fe Modelmentioning

confidence: 99%

Dense Granular Columns in Liquefiable Ground. I: Shear Reinforcement and Cyclic Stress Ratio Reduction

Rayamajhi

Ashford

Boulanger

et al. 2016

J. Geotech. Geoenviron. Eng.

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The installation of dense granular columns by various construction techniques can be used to mitigate liquefaction through a combination of densification, increase of lateral stresses, reinforcement, and drainage. The contributing mechanism of shear reinforcement is isolated and explored using nonlinear three-dimensional (3D) finite-element (FE) analysis. FE models representing both dry and saturated conditions were developed to evaluate cases with and without generation and dissipation of excess pore-water pressures. The shear stress and strain distributions between the granular columns and surrounding soil, and the level of shear stress reduction, were investigated for a practical range of treatment geometries, relative stiffness ratios, vertical stresses, and relative densities of the surrounding soil. A set of 10 acceleration time histories were used as input motions. The FE results show that granular columns undergo a shear strain deformation pattern that is noncompatible with the surrounding soil. As such, the achieved reduction in cyclic stress ratios imposed on the treated soil is far less than that predicted by the conventional shear strain compatibility design approach. Reductions in cyclic stress ratios are insensitive to the applied surface pressure, granular column length/diameter ratio (L/D), and relative density of the surrounding soil for the range of area replacement ratio and column-soil shear modulus ratio examined. A modified design equation to estimate the reduction in cyclic stress ratio provided by dense granular columns is shown to provide good agreement with the FE simulation results.

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Section: Fe Modelmentioning

confidence: 99%

Dense Granular Columns in Liquefiable Ground. I: Shear Reinforcement and Cyclic Stress Ratio Reduction

Rayamajhi

Ashford

Boulanger

et al. 2016

J. Geotech. Geoenviron. Eng.

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“…In addition to the referred experimental e orts, numerical studies have been carried out by various codes and platforms. Some notable instances of such studies include: Finn et al [11], Tabesh & Poulos [12], Miyazaki et al [13], Finn and Fujita [14], Klar et al [15], Liyanapathirana and Poulos [16,17], Chang et al [18], Bhattacharya et al [19], Elgamal et al [20], Cheng and Jeremic [21], Cubrinovski et al [22], Rahmani and Pak [23], Asgari and Oliaei [24], Sarkar et al [25], Bouckovalas and Chaloulos [26], Asadi and Shari pour [27], and Lin et al [28].…”

Section: Literature Reviewmentioning

confidence: 99%

Dynamic behavior of large-diameter piles with considering liquefaction under clay layer

Oliaei

Ghotbi

2017

Scientia Iranica

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Abstract. Marine structures are mostly constructed on deep foundations, namely largediameter piles. Such support structures are driven into deposits of saturated granular soil, vulnerable to liquefaction under loadings of dynamic nature, e.g. earthquakes. Although numerous studies have been accomplished to obtain a comprehensive understanding of their performance during liquefaction, a conclusive study has not been presented for the speci c case of large-diameter piles under a clay layer. This issue has great importance in the case of o shore wind turbines, since they are very sensitive to dynamic loadings. In this study, a 3D FEM model was constructed by OpenSeesPL to explore soil and pile responses throughout liquefaction. To capture the precise behavior, a constitutive law based on a multi-surface plasticity was utilized for soil. The described model used in this study is capable of accurate prediction of sand behavior in undrained conditions. Di erent scenarios were tested: variations in pile dimensions, loading frequency, and in uence of clay layer. Sensitivity analyses show that loading frequency, presence of clay layer, and pile diameter could signi cantly a ect the behavior of large-diameter piles in saturated soil conditions.

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“…The combined effect of vertical and horizontal deformation under structure compels them to tilt excessively which may lead to severe damage to an adjacent lighter/heavier structure. Investigations show that prediction of seismic liquefaction potential is highly dependent to the deformations (Asgari et al 2013). This suggests that the seismic remedial designs should be based on displacement criteria rather than the factor of safety against liquefaction.…”

Section: Effect Of Structure Weight On the Seismic Responsesmentioning

confidence: 99%

“…Although recent advances in physical model experiments (Vucetic and Dobry 1991;Pillai and Byrne 1994; Baziar and Dobry 1995; Liu and Dobry 1997;Høeg et al 2000;Boulanger 2003;Carraro et al 2003;Huang et al 2004;Boulanger and Idriss 2006;Polito et al 2008;Hazirbaba and Rathje 2009), field case histories (Adalier et al 1998;Yoshida et al 2001;Bray et al 2004) and computational modelling of liquefaction-induced ground deformation (Di and Sato 2004;Yang et al 2004;Wang et al 2006;Rayhani and El Naggar 2008;Shahir and Pak 2010;Asgari et al 2013) are quite promising, challenges remain on this critical problem.…”

Section: Introductionmentioning

confidence: 99%

Numerical evaluation of seismic response of shallow foundation on loose silt and silty sand

2014

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Numerical simulation of improvement of a liquefiable soil layer using stone column and pile-pinning techniques

Cited by 78 publications

References 33 publications

Dense Granular Columns in Liquefiable Ground. I: Shear Reinforcement and Cyclic Stress Ratio Reduction

Dense Granular Columns in Liquefiable Ground. I: Shear Reinforcement and Cyclic Stress Ratio Reduction

Dynamic behavior of large-diameter piles with considering liquefaction under clay layer

Numerical evaluation of seismic response of shallow foundation on loose silt and silty sand

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