The historic village of Brienz is built on an alluvial fan at the foot of a large catchment area. In 2005, after a period of extraordinarily heavy precipitation, the Trachtbach carried enormous amounts of debris and buried several buildings, a road and a tourist railway. To prevent similar impacts in future, the torrent was tamed with a combination of different protection measures including the GEOBRUGG debris flow barriers.
The three VX ring net barriers in the Trachtbach have an almost identical flume geometry. All three barriers can retain a volume of 4,000 m³ for a total retention capacity of 12,000 m³.
The VX ring net barriers are dimensioned with a a clearly defined overflow section so there is no risk of the debris flow material breaking laterally. The abrasion plate protects the top of the barrier from potential damage by debris that may be present in subsequent flows and overflows. For drilling the anchors and the subsequent assembly of the ROCCO ring nets, a light step excavator was utilized. No heavy machinery was required for assembling the anchorages.
Barrier 1: bottom width 5.5 m / top width 15 m
Barrier 2: bottom width 6.5 m / top width 17 m
Barrier 3: bottom width 7.0 m / top width 20 m
The single UX160-H4 barrier has a retention volume of 6,000 m³. The bottom width of the barrier is 16 m and the top width is 37 m.
In the event of complete barrier activation, the four barriers together provide an unfilled retention capacity of 18,000 m³.