ABSTRACT
The paper describes the enlargement of an existing railway underpass in Brandizzo, Turin, Italy. Variable geometry of consolidation and reinforcement of Glassfiber Reinforced Polymer, with definition of the geotechnical parameters of the soil and the embankment, allowed to perform the complex excavation, with constant verification of design assumptions and operational control of the executive phases. Lateral to the existing underpass on both sides, on the body of the railway embankment, cemented forepoling were performed, defining as a discrete volume of soil improved, like an earth retaining wall. A series of subhorizontal nails made from inside the existing underpass, has represented a tie for the underpass. During jacking phase of new reinforced concrete element, bigger than the existing underpass, demolition has involved at the same time the old underpass, and the excavation of two lateral parts of embankment.
