3D Coupled Mechanical and Hydraulic Modeling of GESC-Supported Embankments under Cyclic Loads
Publication: International Journal of Geomechanics
Volume 24, Issue 9
Abstract
To date, the traffic-induced dynamic behavior of geosynthetic-encased stone column-supported embankments (GESC) under traffic cyclic loads accompanied by embankment consolidation has not been well studied. Three-dimensional (3D) coupled mechanical and hydraulic modeling is performed using FLAC3D, which considers the fluid flow during the lifespan of three stages: (1) embankment construction (EC): (2) consolidation (C) under embankment surcharge; and (3) cyclic loading (CYC). During the simulation, excess pore pressure, stress concentration, settlement, and lateral displacement are monitored, and the total settlement and lateral displacement could be easily obtained by accumulating the components of the three stages. Parametric analyses are conducted on the reinforcement forms and cyclic loading characteristics that include the dynamic stress amplitude and loading frequency. The ordinary stone (OSC) and GESCs could reduce the settlement and lateral displacement during each stage by improving the strength of the foundation and accelerating drainage consolidation; however, GESCs outperform the columns without geoencasement. In addition, the stress concentration ratio under embankment filling decreased with the increase in the dynamic stress amplitude and loading frequency, which led to the increase in the percentage of the cyclic loading-induced settlement to total settlement.
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Data Availability Statement
All data, models, and codes generated or used during the study appear in the published article.
Acknowledgments
This research was sponsored by the National Natural Science Foundation of China (NSFC 52078205, 52378340) and the Basal Research Fund Support by Hunan University.
Author contributions: Zeyu Xu for the methodology and writing the original draft. Ling Zhang for conceptualization, methodology, writing, and review and editing.
Notation
The following symbols are used in this paper:
- c′
- effective cohesion (Pa);
- ci
- interaction coefficient between geosynthetic and stone column (Pa);
- E
- Young’s modulus (Pa);
- EIRpwp
- encasement improvement ratio for excess pore pressure;
- EIRs_h
- encasement improvement ratio for lateral displacement;
- EIRset
- encasement improvement ratio for settlement;
- f
- loading frequency (Hz);
- kh
- horizontal permeability coefficient (m/s);
- Ks
- interface shear stiffness between geosynthetic and stone column (N/m3);
- kv
- vertical permeability coefficient (m/s);
- n_middle
- stress concentration ratio at the embankment middle;
- n_toe
- stress concentration ratio at the embankment toe;
- s
- settlement (m);
- sc
- settlement occurs at the consolidation stage (m);
- scyc
- settlement occurs at the cyclic loading stage (m);
- sdiff,emb
- differential settlements at the embankment surface (m);
- sdiff,ground
- differential settlements at the ground surface (m);
- sec
- settlement occurs at the embankment construction stage (m);
- sh
- lateral displacement (m);
- sh,max
- maximum lateral displacement (m);
- stotal
- total settlement (m);
- t
- geosynthetic thickness (m);
- u
- excess pore water pressure (Pa);
- umax
- maximum excess pore water pressure (Pa);
- γsat
- saturated unit weight (N/m3);
- γt
- total unit weight (N/m3);
- Δsh,max
- increment of the maximum lateral displacement (m);
- σd
- dynamic stress amplitude (Pa);
- υ
- Poisson’s ratio;
- φ
- effective friction angle (°); and
- φi
- interface friction angle (°).
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Information & Authors
Information
Published In
International Journal of Geomechanics
Volume 24 • Issue 9 • September 2024
Copyright
© 2024 American Society of Civil Engineers.
History
Received: Nov 11, 2023
Accepted: Mar 4, 2024
Published online: Jun 27, 2024
Published in print: Sep 1, 2024
Discussion open until: Nov 27, 2024
ASCE Technical Topics:
- Continuum mechanics
- Coupling
- Cyclic loads
- Dynamic loads
- Dynamics (solid mechanics)
- Engineering fundamentals
- Engineering mechanics
- Hydraulic loads
- Hydraulic models
- Models (by type)
- Solid mechanics
- Structural dynamics
- Structural engineering
- Structural members
- Structural systems
- Three-dimensional models
- Traffic models
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