ABSTRACT
The construction of the twin bore 16.1km Chiltern Tunnels for HS2 by Bouygues Travaux Publics (BYTP) enabled multiple advancements in innovative tunnelling. This paper examines the innovations implemented in their 10.2m diameter Variable Density Tunnel Boring Machine (TBM), which have significantly enhanced productivity, safety, and sustainability in the construction of the tunnels.
In partnership with Herrenknecht, multiple automation systems were incorporated on the TBM. These include: a robotic system, called Krokodyl, for removing wooden spacers between tunnel segments; ATLAS which enables semi-automatic and automatic ring building; a semi-automatic slurry system which makes it possible for the pilot to manage the 16km slurry circuit while remaining focused on mining parameters and the Centre of Thrust (CoT) which simplifies TBM steering. Krokodyl and ATLAS remove the hazard of people plant interface, manual handling, and working at height. The CoT allows for continuous mining by removing pairs of thrust cylinders to enable ring erection while still excavating.
Another key innovation is the integration of recycled water injection on the TBM reducing slurry feed flow and the size of the pumps and slurry pipes. This led to significant reduction in power and freshwater consumption with the associated benefit of carbon reduction and cost savings.
Development of an inert polymer in the Slurry Treatment Plant to process filter cakes is a first in the UK. This innovation enabled landscaping of 3 million cubic meters of spoil on site by removing the need for lime and acid treatment. This presented significant improvements in environmental sustainability, removed tens of thousands of lorry movements from local roads, and avoided the risks of operatives working with acid.
These innovations demonstrate BYTP's commitment to push the boundaries of tunnelling technologies and set new standards for projects worldwide, enhancing productivity, safety and environmental sustainability.
