Crossrail’s first two tunnel boring machines (TBMs) will arrive in London early next year ahead of being launched from Royal Oak for the western running tunnels. Construction of the project’s 21km twin bores will involve at least seven TBMs – each 120 metres in length and weighing 850 tonnes – which will undertake ten individual tunnel drives to construct the six-metre diameter bores. The need for an eighth is currently being assessed for the short drive between Limmo Peninsula and Victoria Dock Portal (Drive G).
Two different types of TBM will be used, reflecting the differing ground conditions along the route. All but one will be Earth Pressure Balance Machines, passing through ground which is predominantly London clay, sand and gravels. The Thames Tunnel, mostly through chalk, will use a Slurry TBM.
Meanwhile, structural building work has been completed on Crossrail’s Tunnelling & Underground Construction Academy in east London. It will offer training to at least 3,500 people needed for delivery of the project and will be fully open by September.