Three-Dimensional Numerical Analysis of Geosynthetic-Reinforced Embankment over Locally Weak Zone

Abstract

This paper presents a three-dimensional numerical analysis using PLAXIS 3D software of geosynthetic-reinforced embankment over locally weak zones (LWZ). The case study considered here is the construction of road embankment reinforced by geosynthetics on soft sabkha soil of Chott El Hodna in Algeria. The construction site of this project presents a high risk of crossing locally weak zones which are characterised by very high compressibility and liquid consistency. The main objective of this paper is to demonstrate the three-dimensional (3D) effects on the differential settlement of geosynthetic-reinforced embankment over locally weak zone. The influence of some parameters, namely the height of the embankment, the stiffness of the geosynthetic, the diameter of the locally weak zone and the friction angle of the embankment fill is also analysed. By comparing the results of 2D and 3D numerical analyses, it was demonstrated that the 3D effects have a great influence on the load transfer mechanisms within the geosynthetic-reinforced embankment. In addition, the results show that the 3D settlement predictions were lower than the corresponding values from the 2D predictions due to the higher arching effect predicted by the former. Further, the results of the parametric study indicate that the arching effect is strongly affected by the height of the embankment and the diameter of the locally weak zone.