Coupled Finite Element Modelling of Geosynthetic Reinforced Embankment Slope on Soft Soils Considering Small and Large Displacement Analyses
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The behaviour of a real case of geosynthetic reinforced embankment slope (GRES) over soft cohesive soils with a prefabricated horizontal drains system (PHDs) was studied by two-dimensional finite element method, considering both small and large displacement assumptions. In order to determine the input geotechnical parameters accurately, laboratory tests and finite element back analysis were carried out. Coupled mechanical and hydraulic analysis was conducted to predict time-dependent behaviour of GRES under staged loading applied in the undrained conditions. The main objective of this study is to assess the effects of changes in geometry on deformation and stress behaviour during the consolidation process. Indeed, the developments of the settlement, horizontal displacement, excess pore pressures, normal effective stress and shear stress during and after construction periods were investigated. According to the large displacement computation results, the combined use of geosynthetic reinforcement with PHDs significantly reduces both the settlement and horizontal displacement but increases pore pressures. Therefore, the required number of construction stages can be reduced. The results of small and large displacement analyses show that the shear strength improvement in the upper embankment part is induced by the combination of surface roughness (skin friction) and arching effects within the embankment fill, while in the lower part it is mainly due to the confinement effect.
KeywordsGeosynthetic reinforced embankment slope Large displacements Coupled analysis Consolidation Confinement Arching effect
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