Here's an outline of these differences:
1. Tunnel Entrance
Accessibility:
Easier access for larger machines and auxiliary equipment.
Machines with higher capacity may be used since space is less constrained.
Mobility:
Machines with wheels or tracks for easier transportation to the tunnel face.
Flexibility to handle different terrain outside the tunnel.
Spraying Distance:
Longer spraying reach may be required due to open space.
Environmental Considerations:
May encounter temperature or moisture variations that can affect the shotcrete mix.
Power Supply:
Usually easier to access external power sources.
2. Inside the Tunnel
Compact Design:
Machines must be compact to navigate narrow, confined spaces.
Lightweight and maneuverable designs are critical to prevent obstructions in small tunnels.
Ventilation and Dust Control:
Wet shotcrete machines should minimize dust generation in confined spaces.
They may include features like water mist systems to control airborne particles.
Adaptability:
Ability to work on uneven surfaces or within curved sections of the tunnel.
Adjustable arms and hoses for spraying overhead or on walls.
Spray Efficiency:
Consistent spray quality with a controlled flow rate for uniform application.
Reduced rebound to minimize waste in confined areas.
Durability and Maintenance:
Machines designed to withstand high humidity, dripping water, and abrasive tunnel environments.
Easy maintenance to reduce downtime in remote locations.
Power Supply:
May rely on onboard power systems or compressed air due to limited electrical access.
Safety Features:
Enhanced lighting for visibility.
Anti-slip and stable operation on uneven surfaces.
Summary
While the entrance allows for larger, more flexible machines, the interior demands compact, durable, and highly efficient equipment tailored for limited space and challenging environments. Equipment selection should prioritize safety, adaptability, and spraying precision to meet the specific challenges of each area.
