Work on the construction of the new collector on Česká has reached the stage of the actual excavation. This work was preceded by the necessary relocation of surface networks, the construction of a temporary water supply system, and the reinforcement of buildings on the street with jet grouting. Miners will be digging underground for approximately one year, after which the surface of the street will be repaired.
“For the last year, the contractors have been working at the surface, carrying out the necessary steps prior to the actual excavation of the collector,” said Brno Mayor Markéta Vaňková. “This involved the relocation of engineering networks – primarily the water, steam, and gas pipelines. This brought with it restrictions for local residents, businesses or pedestrians. I would like to thank everyone for their patience and I now wish the miners an excavation that will go without any problems.”
An equally important part of the work was securing the buildings in the street. “This was carried out using modern jet injection technology,” added Brno’s Deputy Mayor for Investments, René Černý. “Rows of cement columns were created underground, thanks to which the properties are now secured below the collector floor level. The surface above the ceiling of the future collector was also reinforced using low-pressure injection. Thanks to this, a cemented layer was created here, which helps protect the surface during underground work. The current state of Česká is provisional, the street surface will be repaired when the underground work is finished. Instead of asphalt, Česká will be paved and the street will thus get the look it deserves.”
The excavation is being carried out using a classic mining approach, the so-called New Austrian Tunneling Method. To ensure stability, mining reinforcement and shotcrete are used. The construction workers are proceeding from two shafts, each approximately 10 metres deep. The first, Karolínka, is located at the intersection of Česká, Veselá and Solniční. The second, Maruška, is on Středova. The excavation is thus taking place from both ends of the tunnel. The location of the section currently being mined will be marked on the surface by a mobile safety barrier, which will be moved as the work progresses.
According to Michal Chládek, chair of the Board of Directors of the Brno Technical Networks municipal company, the final collector will be 235 metres long, with 21 branches to properties and three technical chambers. Once it is finished, it will contain and protect water, sewage, heating, and high-voltage cables, for all connected properties along the street. Any repairs or accidents can be addressed by the administering authority without the need for excavation on the surface.
If you would like to know what the inside of a secondary collector looks like, you can find a life-size inflatable model in the courtyard of the New Town Hall until the end of September.
Further news and more information about the collector can be found on the project page.
