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S.S. 318 “Valfabbrica (PG)”

Retaining structures

Project name S.S. 318 "Valfabbrica (PG)" Volume 20.000 m³ expanded clay 0-30 mm Location Valfabbrica (PG), Italy Year 2013-2015
Contractor Carena S.p.A. Designer Anas SpA, GP Ingegneria Srl Owner/Builder Anas SpA

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

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