In the San Martín Railway Viaduct, one of the most important railway project carried out in the Autonomous City of Buenos Aires, it was planned the construction of steel strip reinforced soil walls (up to 6 m high), placed over a 6 m (approximately) thick soft clay, underlined by a stiff soil.

In order to reduce the settlement of the reinforced soil walls and of the track structure, different solutions have been considered: total replacement of the compressible layer by compacted silty soil fill; partial replacement by controlled density fill trenches, throughout the entire length of the embankment; foundation on piles, micropiles, gravel columns, arranged in staggered rows; vertical drains.

The works started with the construction of controlled density fill piles 50 cm in diameter, founded in the stiff soil layer. Nano-polymeric geocells have been used in order to evenly distribute the embankment weight and the railway load to the piles.

As the aforementioned solution was failing to meet the project deadline, an alternative solution has been studied: partial replacement of the compressive layer (3 m in depth) and the lay down of two layers of nano-polymeric geocells; one placed just beneath the leveling pad of the reinforced soil walls, and the other one placed at the base of the excavation, acting as separator between the embankment fill and the natural soil.

Finite element method analysis has been carried out, and the results showed that the proposed solution did not result in any issues, in terms of deformations and settlement of the walls and track structure; at the same time, the solution allowed the construction company to meet the project deadline.