QUEENSLAND'S GERMAN CONNECTIONS - PAST, PRESENT AND FUTURE

The crushed rock went to a number of places: some to the airport precinct, used for reclaiming land for future uae there, some trucked to residential developments around and outside Brisbane. In February and March 2011, Rocksy and Sandy broke through into Wooloowin’s 23m-wide caverns on their way from Kalinga Park. Less than six months later, both machines completed excavation as they broke through into the Lutwyche caverns, within days of each other. Because the TBMs could not go backwards, they couldn’t return to their entry point, so it wasn’t practical to remove the cutting head and shield at the completion of its work. A shaft up to the surface could have been built but this would have emerged in the middle of the Lutwyche shopping centre, (“a far from practical option” as Charles dryly noted), so the only direction was down. The ‘working bodies’ of the TBMs (of course, narrower in diameter than the heads) were progressively withdrawn and disassembled back on the surface. After breakthroughs the cutting heads and shields from both TBMs were lowered into purpose-built shafts deep below the floor of the Airportlink tunnels. Measuring 14.5m wide and 16.5m deep, the two burial pits required 2,500m 2 of concrete pumped continuously to bury the remains of these giant machine segments. They lie far beneath Chalk Street, an unseen and soon-forgotten legacy of German engineering excellence. Unheeded since the successful opening of the AirportlinkM7, they will be unremembered for the difference they will have brought, one of a trio of traffic tunnel projects, to Queensland’s fast-growing capital city. Legacy under Lutwyche

Below: A graphic representation of a TBM’s intestines, as it progresses from the right; at the end a one-way journey, only the head and widest shield (at the left) cannot be withdrawn and may be left behind – all the backup equipment shown in the almost 200m-long body is disassembled and withdrawn. Image courtesy Herrenknecht AG

Left: A TBM segment is unloaded onto a heavy transporter on a wharf on the north side of the Brisbane River and, in the sequence (above) a proud group of workers in front of one of the cutting heads, before it is lowered into position and, months

later, the moment of breakthrough! Images courtesy BrisConnections

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