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Geosynthetic-reinforced piled embankments have been increasingly used as a solution to stabilize embankments on soft subgrades. Analytical methods have been commonly used in routine designs of such works and significant deviations between results can occur depending on the method considered. This paper investigates the accuracy of different analytical methods by comparing their predictions with results of large-scale tests. A section of piled embankment consisting of an instrumented fill layer subjected to varying values of surface surcharge was simulated in the laboratory. Four different reinforcement types were tested. Results of the tests are presented and discussed, and statistical analyses were carried out to assess the accuracy of each method with regard to pile efficacy, maximum fill settlement, and reinforcement strain. Results show that the identification of the most accurate and precise method depends on the statistical criterion used. However, in general, the methods based on the concentric arches theory, the modified British method (BS8006), and the German method (EBGEO) were the ones that showed the best predictive capability. Key words: geosynthetics, piled embankments, reinforcement, analytical methods. Les remblais geosynthetiques renforces ont ete de plus en plus utilises comme solution pour stabiliser les remblais sur les sous-sols souples. Des methodes analytiques ont ete couramment utilisees dans la conception de routine de tels travaux et des ecarts importants entre les resultats peuvent survenir en fonction de la methode consideree. Cet article examine la precision de differentes methodes analytiques comparant leurs predictions avec les resultats de tests a grande echelle. Une section de remblai empile constituee d'une couche de remplissage instrumentee soumise a des valeurs variables de surtaxe de surface a ete simulee en laboratoire. Quatre types de renforcement differents ont ete testes. Les resultats des tests sont presentes et discutes, et des analyses statistiques ont ete effectuees pour evaluer l'exactitude de chaque methode en ce qui concerne l'efficacite des pieux, le tassement maximal du remplissage et la deformation de renforcement. Les resultats montrent que l'identification de la methode la plus precise et la plus precise depend du critere statistique utilise. Cependant, en general, les methodes basees sur la theorie des arcs concentriques, la methode britannique modifiee (BS8006) et la methode allemande (EBGEO) etaient celles qui presentaient la meilleure capacite de prediction. [Traduit par la Redaction] Mots-cles: geosynthetiques, remblais empiles, renforcement, methodes analytiques., Introduction Settlements of embankments on soft subgrades can be reduced significantly with the use of piles or granular columns. In addition, overall stability is improved or guaranteed because the presence [...]

Geosynthetics can be used in several applications in geotechnical and geoenvironmental engineering, being geotextiles the most traditional and versatile type of geosynthetic. One of the applications of geotextiles is in separation between good and poor quality soils. This situation may occur in geotechnical structures such as roads and railways constructed on soft saturated subgrades. The presence of a geotextile separator avoids or minimize the contamination of the good quality base or ballast material with fines from the subgrade, increasing the life of the road and reducing maintenance costs. Despite its importance, very few studies on the behaviour of geotextiles in separation can be found in the literature compared to other applications of these materials. This paper investigates the performance of nonwoven geotextiles in separation. Laboratory tests on geotextiles with masses per unit area ranging from 200 g/m2 to 600 g/m2 were executed using an apparatus capable of applying repetitive loading to simulate traffic conditions. Measurements of surface displacements and pore pressures in the subgrade soil and the evaluation of geotextile mechanical damages at the end of the tests were carried out. The results obtained showed that the three geotextiles tested were effective separators, avoiding contamination of the base soil and accelerating the dissipation of excess pore pressures in the subgrade soil. However, significant mechanical damage was observed in the lighter geotextile used. [ABSTRACT FROM AUTHOR]