Spring 2010

TenCate Polyslope® for protection against avalanches

Imagine that you want to protect a popular ski resort in the Tyrol (Austria) against avalanches but the natural condition of this mountainous area rule out traditional solutions. In addition, the barrier has to fit appropriately into this landscape. Well then you opt for a solution with a system based on reinforced geosynthetics, such as TenCate Polyslope® S. The barrier near Dias Alpe is proof of this.

The avalanche barrier near Dias Alpe is perhaps the largest barrier in the world that avalanches can encounter on their way down. The barrier is siatuted 2,200 metres above sea level and guards the place Kappl against all too powerful masses of snow. The barrier was contructed using natural materials that are available locally. TenCate Polyslope® S is an environment-friendly and attractively priced system for constructing retaining walls. It consists of three components: geosynthetics for reinforcement (TenCate Polyfelt®), erosion protection using fibre glass, and steel formwork (TenCate Miragrid®).

The mountains around Kappl are funnel-shaped, which virtually guides avalanches directly towards the village. Due to the natural conditions of the area, it is not possible to install protection at the top of the mountain and protection nearer the village provides just as little relief: at this stage avalanches already have too much mass and kinetic energy. This is the reason for constructing a barrier at a level where it will break up the avalanche before it has reached its highest speed and force. The length of the barrier is 600 metres and it is 25 metres high. Some 400,000 m³ of soil had to be moved and 285,000 m² of geosynthetics were required.

The idea behind this system is that the area will become entirely covered in vegetation. In view of the fact that thriving plant growth cannot be guaranteed at 2,200 metres, it was decided to use galvanized frames, which will help to provide a longer time for growth to become established. These geogrids are folded back over the layer above, which provides extra safety when such dynamic forces are at play.


Blue fabric (Tecawork Blue 65287)