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  • Technical Concept

    Design Principles

    The TUM Boring TBM Design is based on a balanced mix between industry standards principles like pipejacking and multiple innovative approaches to solve inefficiencies and increase tunnelling rates. This method has several advantages: fast tunnelling feed rates, robust pipe segments with pre- installed driving surfaces, many off-the-shelf components, and many more, which were decisive for our team.
    The main task of our cutterhead is to dig a tunnel with a diameter of approximately 0.5 m. It consists of a cutting wheel, rotating drum, housing, sealed bearing, mechanical face sealing, ring gear, four synchronous motors and an auger with the relevant housing and bearing.
    Steering System
    The steering system makes sure we stay right on track and makes small correction movements in correspondence to the guidance system. It has integrated hydraulics and many sensors to allow precise steering.
    The Guidance System aims to measure the TBM‘s diversion from the planned tunnel axis. As we are drilling a straight tunnel, we decided on a laser guidance system. We can precisely measure the TBM’s heading by measuring the machine’s offset in reference to a laser beam representing the tunnel axis.
    Control System
    The control system acts as a brain for the entire TBM. It receives signals from our almost 30 sensors and 15 actuators and evaluates them accordingly. This control system is implemented on a state-of-the-art programmable logic controller (PLC).
    The jacking system consists of 2 clamps; each is propelled with four hydraulic cylinders. The system can be operated in a continuous mode, which supports jacking forces up to 500 kN or a discontinuous mode, providing forces up to 1 MN. Our calculations show that the constant pressure of 500 kN is sufficient for the conditions in the U.S., and the discontinuous mode is only used as a backup.
    Since we are planning to build the tunnel as quickly as possible, we constructed a revolver pipe storage that contains all tunnel segments. This allows us to quickly switch to the next segment with minimal downtime thanks to a motor-driven gear system that rotates our revolver and prohibits unintended movement.
    Material Removal
    The material removal system consists of 6 conveyor belts integrated into the pipes we use to construct the tunnel structure. It also includes an auger conveyor, which enables removing all mined material from the drilling process.
    Power System
    Power is needed for all sensors and actuators in the TBM. Our water-cooled synchronous motors drive the cutter head. The water-cooling with our self-designed cooling plates allows us to achieve the highest possible power density in the cutter head in a confined space.
    Soil Conditioning
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    A Vision Becomes Reality

    Following our technical concept which was finalized in February 2021, we have started constructing our TBM. Having completed most of our testing, the TBM will now be shipped to the US. This hands-on and remarkable work would have never been possible without the generous support from our partners.


    Our TBM has been optimized for use in the Not-a-Boring Competition. With our design, we aim to achieve optimal speed. At the same time, our machine is integrated in a 40ft shipping container. That makes it ideally suited for transport since we can rely on the standardized infrastructure of the logistics industry.

    Total Weight
    22,000 kg
    Inner Tunnel Diameter
    540 mm
    Propulsion Force
    500 kN / 1 MN (discontinuous mode)
    Machine Dimensions
    12.2 m (length) × 2.4 m (width) × 2.6 m (height)

    Watch out, Gustl! We're catching up.

    Our boring machine will rival a snail in speed. This is significantly faster than industry standard.

    Gustl is our pet snail