problem
The new south ring road around the city of Vicenza, Italy, allows drivers to easily commute, and it solves a traffic congestion problem. Construction of the road was planned over highly saturated soft clay with low bearing capacity, meaning that settlement could take place during or after construction, with serious consequences for the life span of the road. The base layer, made up from granular material, can sink into the foundation soil, and horizontal and vertical movement capable of forming ruts can occur at the base.

solution
To avoid the differential settlements, it is necessary to place one or more layers of reinforcing geogrids, having the ability to confine the aggregate and distribute the load.
Any increase in load may result in an increase of pore water pressure, and in impermeable soils. This water dissipates very slowly, causing instability of the soil and potential slip plane failures.
A vertical drainage system using PVD drains allows for a faster removal of excess pore water, faster consolidation rate, thus decreasing the risk of slip plane failure. The design for the Vicenza road, carried out by highway consultants with project designer SEPI of Italy, required the construction of a geogrid reinforced raft comprising two layers of an integral extruded geogrid and two nonwoven geotextiles (Fig. 1).
The contractor, ATI Astaldi-Mantovani, working on behalf of the client Autostrada BS-VR-VI-PD, proposed the use of TENAX LBO 201 SAMP bioriented geogrids, which met the requirements of the design specification.