Tunnel boring production is often limited by the speed of muck removal and the supply of critical construction material to the TBM. The back-up system, or trailing equipment, is as important as the machine itself. That’s why Robbins pays as much attention to the engineering of the back-up as it does to the TBM.
From simple, short gantry systems to sophisticated, remote-controlled double-track systems, Robbins matches the back-up system to the construction method and type of TBM. Robbins will help you decide which proven system is best for your job. Robbins offers tracked systems using muck trains or conveyors as well as trackless systems using conveyors or rubber-tired vehicles.
A single-track back-up system has the advantage of being short, simple to operate and simple to maintain. If your tunnel is small in diameter, short in length, or the equipment assembly area is restricted, a single-track back-up is often the best solution. Similarly, single-track systems are frequently used if the TBM must start from the bottom of a shaft. Depending on your construction schedule and requirements, single-track systems can be used with continuous conveyors or with muck trains.
When using muck cars in large-diameter tunnels, double-track back-up systems ensure maximum production. By installing a California switch behind the back-up, empty muck cars can be kept near the loading point while others are being filled. This minimizes delays between trains and optimizes advance rates.
Rubber tired vehicle back-up systems allow muck to be removed by conveyor or truck. This permits roadbed construction to be carried out simultaneously with tunnel excavation. As a result of this flexibility, they are often used in large diameter tunnels for rail, road, and hydroelectric projects.