A3 highway reinforced soil slope

Italy, Lagonegro (PZ) 
PET woven geogrids with PVC coating as a structural element for reinforced soil slope construction

Problem:
the enlargement of the A3 Salerno-Reggio Calabria highway requires the construction of various types of retaining systems, including bulkheads, reinforced concrete retaining walls and reinforced soil. With reference to this type of works, it was supplied SIS scpa contractor materials, technology and technical support for reinforcement slopes named TR23. The reinforced slope has a maximum height of 16.90 m.
The site soil consists of two layers of soil defined UG6a and UG6b.
The first, with a maximum thickness of about 4 m, consists of composite flysch deposits alternating with brown and black clay, and silica-bearing calcilulite with relatively modest mechanical properties. This has required deep soil improvement with burying the first courses of the reinforced soil slope. Below the top clay strata is the UG6b unit, Flysch clay, very similar to the UG6a unit but with better mechanical propertieswith better mechanical properties.

Solution:
the solution supporting the road overloading, able to guarantee the stability of the road surface while allowing excellent integration in the surrounding environment, was performed on soil reinforced with Edilgrid, a PET woven geogrid with PVC coating.
It has a tensile strength of 35-55-80-110 kN/m, low tensile strain at failure, provides low tensile creep, good durability and mechanical protection, and is extremely simple and quick to install.
The anchor length of the first layers of geogrid, starting from the ground level is equal to 14.00 m. The TR23 works are reinforced embankments that belond to the reinforced slopes category, with a face inclination of 63° and 65 cm thick compacted soil layers. It consists of three steep slopes.
The first starts at ground level with a height of 7.15 m, followed by 1.0 m flat tread (constant dimension also for the other flat treads). Then the second slope starts, with a maximum height of 4.55 m, followed by the second flat tread. Lastly, the last slope starts with a height of 5.20 m. Then, there is a small 34° embankment with height of 1.30 m.
The reinforced soil has a linear extension of about 216 m, with a total surface area of 2000 m2. Given the particular height of the works and the critical stratigraphic situation, numerical analysis was performed in addition to classic inspections to better understand the behavior of the works. After a short time, the face is completely re-grown and the works are perfectly integrated in the surrounding environment.