During construction of the headrace tunnel in July 2012 for a hydro power plant some severe rockburst occured. The high internal stress in the rock and overburden over 1000 m on top of the tunnel as well as the brittle metamophic character with a rock mass rating RMR › 65 caused some severe problems during the project.
The tunnel was divided in sectors to analyse the stress level in regard to the high stress classification whereas it shows that some rockbursts of level 2 and 3 occured. In the most critical zone a support system with MINAX® 80/4 was applied in combination with mechanized installation thanks to Geobrugg's MESHA® handler. The installation time had been decreased between 20 to 25% and safety for workes was significantly improved.