Tunnel boring machine

Tunnel Boring Machines In hard rock nothing bores tunnel faster than a Main Beam TBM. If you want to bore a tunnel through hard rock in the shortest time possible, then the Robbins Main Beam TBM is the right solution. Get the best machine for the job and the most experienced team working with you. The results will be greater reliability, higher advance rates, and record-breaking performance. WHAT IS A MAIN BEAM TBM? A Robbins Main Beam TBM is complex in its design, yet relatively simple in concept. The front of the TBM is a rotating cutterhead that matches the diameter of the tunnel. The cutterhead holds disc cutters (ranging from 14″ to 20″ in diameter) which are positioned for optimal boring of the given rock type. As the cutterhead turns, hydraulic propel cylinders push the cutters into the rock. The transfer of this high thrust through the rolling disc cutters creates fractures in the rock, causing chips to break away from the tunnel face. A unique floating gripper system pushes on the sidewalls and is locked in place while the propel cylinders extend, allowing the main beam to advance the TBM.