S.S. 318 “Valfabbrica (PG)”
Retaining structures
Problem/solution:
The route for a new road ss 318 km between km 13 and 17 near Valfabbrica (PG) passes through a mountaineous area with risk of landslides. In one of these areas, the design engineers decided that the best solution was to create a lightweight embankment with expanded clay reinforced with geogrids.
Why Expanded Clay:
A lightweight embankment with expanded clay was chosen as a solution, in order to keep load weights on the slope to a minimum, as any increase in weight is dangerous to the stability of the slope. This is also an area with frequent and heavy rainfall throughout the year, expanded clay is a material that drains well and helps to avoid overloading due to water.
Experience:
The embankment was built with alternating layers of 70 cm of expanded clay with geotextile on top, and 30 cm of granular normal local aggregate , each layer of granular normal aggregate was passed over by a roller to optimize the compaction of the embankment. These layers were repeated for the whole height of the embankment.
Key Issues:
Drainage, Earth preassure, Settlement, and Stability