Work has begun on one of the most significant tunnelling projects in the HS2 scheme, which will bore a deep tunnel underneath the Chiltern Hills to take the route northwards out of London en route to Birmingham.
A 2,000-tonne boring machine known as Florence – female names are traditional for such machines – has begun the task. It is one of ten that will be involved in the huge excavation project that will dig 64 miles of tunnel between London and the West Midlands. A second machine called Cecilia will start work at the south portal site soon.
The Chilterns tunnel will be ten miles long and help preserve the peace and serenity of the designated Area of Outstanding Natural Beauty (AONB) at surface level.
Not everyone is satisfied with this, however; the authorities responsible for the preservation of the AONB – Buckinghamshire Council and the Chilterns Conservation Board – have expressed concerns that the work may negatively impact on chalk streams and underground aquifers.
Chalk streams represent a very rare habitat found mainly in the Chilterns and other parts of southern and eastern England.
Dealing with sensitive environmental issues is one key part of the project and a reason that which specialist plant hire services are needed, in order to ensure the right equipment is used in the correct way to minimise damage to habitats and environments, either at the surface or underground.
Welcoming news of the start of tunnelling work as “a major moment of progress for the HS2 project”, HS2 Chief Executive Mark Thurston called on the country to get behind the project, which some have opposed on cost grounds as well as for environmental reasons.
He noted: “With more than 16,000 jobs already supported by the project and thousands of companies big and small benefiting from contracts, HS2 is providing a major boost to the economy.”
The Chiltern tunnels are just the first of many HS2 tunnels being dug in some very different settings across the country. These will also include urban locations such as west London, south Manchester and under Crewe town centre, as well as rural locations like Long Itchington wood in Warwickshire.
In the case of Long Itchington and some other rural tunnels, such as Wendover, the tunnel will be developed by the cut-and-cover method, rather than deep tunnel boring.
These two different methods can be seen with underground railway tunnels. The London underground originally used cut-and-cover for its wider, sub-surface tunnels such as that seen on the Circle line, while the development of the shield tunnelling machine enabled deeper, rounded tunnels to be cut.
Other recent developments for HS2 include the awarding of the contract for the construction of the Curzon Street station in the heart of Birmingham. Last week, Mace Dragados won the race for the £570 million project to design and build the station to the highest BREEAM energy performance standards.
Mace Dragados already has a record of major railway station development in the city, having previously delivered a large-scale refurbishment of Birmingham New Street. It is also working on the London HS2 terminus at Euston.