Wet Shotcrete Machine Process for Tunnel Surfacing:
Mixing and Preparation:
The concrete mixture is prepared in a batching plant, ensuring precise control over the water-to-cement ratio and other components.
The mixture is fed into the wet shotcrete machine, which consists of a pump and a spraying nozzle.
Transport and Spraying:
The machine pumps the pre-mixed concrete through a hose.
At the nozzle, compressed air is added, propelling the concrete mix at high speed onto the tunnel surface.
Nozzle operators control the flow and direction to ensure an even application.
Bonding to the Surface:
The high velocity of the concrete ensures good adhesion to the substrate (rock, soil, or concrete).
Fiber reinforcement can be added to improve strength, flexibility, and crack resistance.
The operator maintains a consistent distance from the tunnel surface to achieve uniform thickness and avoid rebound loss.
Curing:
After spraying, the wet shotcrete undergoes a curing process to reach its full strength.
Proper curing is essential to avoid cracking and ensure long-term durability.
Advantages:
High productivity: Faster application compared to traditional methods.
Low rebound: Minimal material waste as most of the shotcrete adheres to the surface.
Flexible application: Ideal for irregular or curved surfaces like tunnel walls.
This method is widely employed in mining, underground construction, and infrastructure projects due to its efficiency and adaptability.
