Where highway alignments pass through rock formations by means of cut excavations, very steep rock cut slopes may be formed. If the rockfall catch ditch is not sufficiently wide, fragments detaching from the rock slope may fall onto the highway and create a serious risk to life and property. Depending on project-specific conditions and available space, various mitigation measures can be implemented to eliminate this risk. One of these measures is to realign the highway section and widen the rockfall catch ditch.
Another mitigation measure is the construction of a reinforced concrete protection structure along the highway section exposed to rockfall hazard (Figure 1). Where such a reinforced concrete protection structure is constructed, the structure itself must also be protected against damage caused by falling rock fragments. For this purpose, the space between the protection structure and the rock slope can be filled with geofoam blocks. In this application, the geofoam blocks act as a “buffer,” deforming under high-energy impact from falling rock fragments and absorbing the impact energy, thereby helping to prevent damage to the protection structure.
The geofoam block application implemented on a protection tunnel constructed against rockfall hazard along the Çiftehan–Pozantı section of the Adana–Pozantı Motorway is an example of this type of application in Türkiye (Figure 2).
