from HS2
We are writing to update you on some planned works in your local area.
Tunnelling in Hillingdon:
Our tunnel boring machines (TBMs) have begun their tunnelling journey to construct tunnels under Hillingdon. We expect TBM Sushila constructing the Birmingham tunnel to have passed under Ickenham Close by mid-December, with TBM Caroline in the same location in January.
The tunnel boring machines will stop for maintenance between 23 December 2022 and 4 January 2023. We will resume tunnelling on 5 January and expect TBM Sushila to pass under the Metropolitan line towards the end of January.
What we are doing
Tunnels construction so far
Our tunnel boring machines (TBMs) have begun their tunnelling journey to construct tunnels under Hillingdon. We expect TBM Sushila constructing the Birmingham tunnel to have passed under Ickenham Close by mid-December, with TBM Caroline in the same location in January.
What to expect
The tunnel boring machines will stop for maintenance between 23 December 2022 and 4 January 2023. We will resume tunnelling on 5 January and expect TBM Sushila to pass under the Metropolitan line towards the end of January.
Properties potentially affected by ground movement from tunnelling will already be aware of eligibility for a building condition survey. Our Land and Property team will write to eligible properties with information on how to book a survey. See the table below outlining when you can expect to receive this letter.
Early January 2023 – Herlwyn Avenue
Early February 2023 – Lawn Close, Almond Close, Roundways, West End Road and New Pond Parade
Please book your condition survey as soon as possible after you receive your letter. We will also send you a reminder letter approximately four weeks in advance of tunnelling nearby. Our Land and Property team will be out and about with the community engagement team. It may be possible to book a survey appointment at that time.
Keeping you updated
We will provide updates on the TBMs’ location at https://www.hs2.org.uk/in-your-area/map/
As tunnelling progresses eastwards towards Herlwyn Avenue, Lawn Close and Almond Close, Roundways, West End Road and New Pond Parade, our community engagement team will keep you regularly updated before the TBM is nearby and will follow up after it has passed, which will be no more than a few days.
How we are managing the impacts of tunnelling
TBMs are the best method for safely excavating tunnels of this type because they build the tunnel as they dig. This reduces the risk of settlement (the way ground moves around a hole after it has been dug) and minimises potential for any damage to nearby properties. The TBMs will operate 24 hours a day, 7 days a week until the construction of the tunnel is complete.
Continuous tunnelling by TBMs has been used successfully on major projects such as Crossrail, Thames Tideway and the Northern Line Extension. Extensive knowledge and data gathered from tunnelling in similar conditions enables us to predict ground-borne noise and vibration levels. Our assessments did not predict significant ground-borne noise and vibration impacts. However, it may be possible to hear a low-level sound from the TBMs during quieter periods of time. It is unlikely vibration from tunnelling will cause damage to nearby buildings.
We will be closely monitoring tunnelling progress and will keep you updated on when it is likely that the TBMs will be passing nearby. The duration should be no more than a few days near any one property.
Monitoring taking place during tunnelling
We have installed specialist equipment along the tunnelling route to monitor ground movements before, during and after construction. The surveying team will be out and about in Hillingdon to take regular readings from the studs located in the pavements or to take readings from the equipment mounted on buildings. You may see members of the team assembling a tripod to mount monitoring equipment in order to take readings. This activity will be quiet, for a short duration and will not affect access to footpaths and driveways. We apologise in advance should this activity inconvenience or disturb you.
How are properties protected from the potential impact of our tunnelling works?
- There are legal provisions under the HS2 Act to provide protection should any damage occur from HS2 tunnelling works or excavations.
- Eligible properties within 30 metres of the tunnel route are entitled to a Settlement Deed, a formal legal agreement between HS2 and the property owner.
- HS2 will be responsible for paying for any property repairs related to its works, whether the property owner holds a deed or not.
- If your property is within the 10mm settlement zone (the area which may experience some ground movement after tunnelling), you will have been contacted three months in advance of tunnelling nearby to arrange a building condition survey. The purpose of the survey is to capture the condition of your property as close as possible to the time when tunnelling will take place.
- If, during or following tunnelling, you believe that damage has occurred, you can contact us to let us know. As part of the assessment of a damage claim, a second comparison survey of a property may be undertaken. You can contact the HS2 Helpdesk on 08081 434 434 or email HS2enquiries@hs2.org.uk
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