Shotcrete

Shotcreting is a common method in rock reinforcement

Shotcreting is one of the most important elements in modern rock reinforcement. Shotcreting is used mostly in the reinforcement of rock and soil. The most common applications are traffic tunnels and underground car parks. Our experienced staff and versatile equipment enable effective and safe implementation and high-quality end result to the customer and end users.

Shotcreting is an effective way of reinforcing uneven surfaces of various shapes. As shotcrete will adhere instantly when applied, it is excellent in the following, for example:

• tunnels
• reinforcement and cladding on the walls of vaults and shafts
• tunnel openings
• reinforcement of road banks
• repair and reinforcement of concrete wall bases, beams, pillars and vaults.
  

Work stages

Before shotcreting, the substrate must be prepared to ensure that the concrete will stick to the surface of the rock or other structure.  The can be done by scaling, for example. The idea with scaling is to remove any loose aggregate from the rock surface.

Shotcreting begins with the preparing of the concrete mix. The proportions of the concrete mix are determined on the basis of the application to ensure durability. Once the concrete mix is ready and all other preparations have been completed, the concrete is sprayed using compressed air on the substrate. Depending on the chosen method, the spraying is done either manually or by machine.

Once the concrete has been sprayed, it is allowed to dry sufficiently before the next stage. Thanks to the short drying time, work can continue relatively soon.

Wet and dry shotcreting

We do both wet and dry shotcreting, as both have their benefits. Dry shotcreting equipment is compact. This is why it is a method that is better suited for repairs in small areas and for spaces that should remain dry or are difficult to access. These include shafts, and tunnels that can only by accessed through shafts.

Wet shotcreting, on the other hand, is more efficient and owing to its large capacity, suited for more extensive application. Wet shotcreting equipment is relatively bulky, so the method is suited for sites where the equipment can be wheeled in or where the distance from the equipment to the spray nozzle is short.

We have spray robots and various wet and dry shotcreting equipment for a variety of needs, and we update our equipment and expertise of our staff regularly.

Shotcrete works we have done

• Renovation of the train tunnel, Pepallonmäki, R. Ajalin Oy – Renovation of the Rantarata train tunnel 560 m, drilling of anchor pins, netting, shotcrete, installation of cladding and post-sealing work
• Länsimetro Espoonlahti, Espoo, YIT Infra Oy – Reinforcement works of Espoonlahti metro station shafts, installation and equipment work of shotcrete sub-floor, shotcrete of tunnel 600 m3
• Lippulaivan shopping center, Espoo, Louhintahiekka Oy – Shotcrete of the shopping center’s foundations
• Renovation of the Lavianmäki train tunnel, Destia Rail Oy – Renovation of the Rantarata train tunnel 580 m, drilling of 11,500 dowels, netting 11,500 m2, shotcrete approx. 12,000 m2
• Renovation of HSY Pasila’s water tunnels, Destia Oy – renovation of the narrow water tunnel, drilling and bolting approx. 10,000 m2, shotcrete 12,000 m2, installation of shotcrete drainage system 2,000 m2 and wedge excavation works
• Heat cavern Helen Mustikkamaa, YPR – heat cavern reinforcement work, e.g. drilling, bolting, shotcrete drainage system and shotcrete. 
• Neste Kilpilahti – Porvoon Paalurakenne Oy – wedge excavation and shotcrete for the bottom of fuel tanks
• Högbacka train tunnel renovation, R. Ajalin – shotcrete approx. 5,000 m2
• Plastering of the maintenance tunnel of the Sulkavuori waste treatment plant, YIT