Numerical Simulation of the Load Transfer Mechanism of a Geosynthetic Encased Stone Column Unit Cell under Embankment Loading
Publication: International Journal of Geomechanics
Volume 24, Issue 8
Abstract
This paper presents a numerical study to investigate the load transfer mechanism of a geosynthetic encased stone column (GESC) under embankment loading. The soils were modeled with a nonlinear elasto-plastic constitutive model incorporating a hyperbolic stress–strain relationship and the Mohr–Coulomb failure criterion. The geosynthetic encasement was modeled using a linearly elastic embedded liner element. Two interfaces were used to simulate the interaction between the geosynthetic encasement and the soils on either side. The validation of the numerical model was conducted using test data from vertical loading tests of the individual GESC installed in loose sand, including applied vertical stress–settlement curves and the circumferential strains profiles. Then, the influences of different design parameters on the load transfer mechanism of the GESC unit cell were investigated through a parametric study. Results indicate that the development of stress concentration ratio depends on the mobilization of tensile strains. The circumferential strains are significantly larger than the longitudinal strains, indicating that the circumferential tensile effect is dominant under embankment loading. The load transfer effect was gradually enhanced with increasing tensile strains. Increasing the geosynthetic encasement stiffness can be considered as an alternative to increasing the column infill friction angle in improving the load transfer effect.
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Data Availability Statement
All data, models, or code that support the findings of this study are available from the corresponding author upon reasonable request.
Acknowledgments
This research is supported by the National Key R&D Program of China (Grant No. 2022YFC3080400), the Fundamental Research Funds for the Central Universities (Grant Nos. 2042023kf1014 and 2042023kfyq03), the National Natural Science Foundation of China (Grant No. 52078392), and the CRSRI Open Research Program (Program SN: CKWV2021872/KY). The authors gratefully acknowledge the financial supports.
Notation
The following symbols are used in this paper:
- c′
- apparent cohesion, (kPa);
- d
- column diameter (m);
- J
- geosynthetic encasement stiffness (N/m);
- K
- elastic modulus number (dimensionless);
- Kb
- bulk modulus number (dimensionless);
- Kur
- unloading-reloading elastic modulus number (dimensionless);
- le
- encasement length (m);
- m
- bulk modulus exponent (dimensionless);
- n
- elastic modulus exponent (dimensionless);
- Rf
- failure ratio (dimensionless);
- RLD
- length-to-diameter ratio;
- s
- column spacing (m);
- z
- depth (m);
- γ
- unit weight (kN · m3);
- ϕ′
- friction angle (°);
- ϕ
- soil friction angle (°);
- ϕsc
- column infill friction angle (°);
- ϕsoil
- surrounding soil friction angle (°);
- σv
- vertical stress (Pa); and
- ψ
- dilation angle (°).
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Published In
International Journal of Geomechanics
Volume 24 • Issue 8 • August 2024
Copyright
© 2024 American Society of Civil Engineers.
History
Received: Jul 6, 2023
Accepted: Feb 13, 2024
Published online: Jun 5, 2024
Published in print: Aug 1, 2024
Discussion open until: Nov 5, 2024
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