Safeguarding the intake structure of a hydroelectric power station against avalanches 

Overview

ÖBB, Austrian Federal Railways, a leader in the mobility and transportation sector in Austria, embarked on a significant endeavour to expand a hydroelectric power station. Because of its location, the intake structure of the power station needed an avalanche protection bund at Tauernmoossee, an artificial lake nestled in the central Alps of Salzburg, Austria. Situated more than 2,000 m above sea level, this lake boasts a volume exceeding 20 million m3 of water, feeding the hydroelectric powerplant. The project called for the construction of a 6m high and a 100m long combined avalanche deflection and catchment dam, purposed to shield the intake structure of the by-pass.

Challenge

Given the elevation of the site, the project had a restrictive timeframe of just two months, making early completion paramount due to the onset of winter. Throughout the design process, collaborations were forged with the owner, the designer, and the contractor. The design chosen was influenced by construction costs, availability of resources, and a design proposal put forth by Solmax. The elevated terrain posed significant challenges, chiefly the early arrival of winter. Addressing these challenges demanded strategic solutions. Leveraging delivery from stock and incorporating flexibility in design were key in manoeuvring these challenges. A distinctive feature of this project was the decision to opt for a geogrid reinforced structure, facilitated by the quick and easy construction process.

Solution

Solmax supplied the Polyslope S system consisting of MIRAGRID® GX 55, MIRAGRID Green, steel shuttering elements and locally available fill material. This system was used because it is an approved and certified reinforced soil system, coupled with its availability and the design assistance that came with it. The result was the successful protection of the vast water reservoir.