Rapid Response & Tunnel Access Services for the Thames Tideway Tunnel - Market Engagement

Rapid Response & Tunnel Access Services for the Thames Tideway Tunnel - Market Engagement:

The Thames Tideway Tunnel (TTT) is 25km (15.5m) long, stretching from Acton in west London to Abbey Mills Pumping Station in the east, and is built on a gradient so flows travel west to east. At its deepest, it is 67m underground (33m at its shallowest) and the internal diameter of the tunnel is 7.2m. There are 21 shafts constructed on the project which will be used to divert sewage flows from London’s existing Victorian sewage network to the new 25-kilometre tunnel, which range in depth from c.35-c.65 metres across the project.

Following completion of the Works on the TTT project, Tideway is responsible for maintaining the TTT network during the System Acceptance period which currently runs from approximately mid 2025 for a minimum of 18 and up to a 36-month period. Tideway is therefore exploring service delivery options for rapid response & tunnel access capability across the 21 project sites during the System Acceptance period.

The Service consists of three core elements to be delivered by the Contractor which are summarised as follows:

1. Rapid response tunnel access: In support of search and rescue missions that will be carried out by Tideway’s Search & Rescue Contractor.

Tideway’s Search & Rescue Contractor may be called upon at any time to undertake search and rescue missions in the TTT network. For example, they may be called upon to locate and rescue intruders. Whilst the Search & Rescue Contractor will provide the specialist rescue teams and equipment, their entry to and egress from the tunnel network will be facilitated by the Contractor who will provide the lifting plant and people-carrier baskets that can be rapidly deployed at two project locations simultaneously.

2. Planned tunnel access: In support of tunnel inspections and repairs that will be carried out by Tideway’s Inspection Services Contractor and Others as appropriate.

Tideway’s Tunnel Inspection Contractor will undertake a detailed inspection of the TTT network under a planned tunnel shutdown during the System Acceptance Period. If the inspections uncover defects and/or high levels of sediment in the tunnels that require removal, then a further planned tunnel shutdown may be required during the System Acceptance Period to facilitate the repairs and sediment removal by Other Contractors.

The Contractor will manage the tunnel shutdowns; provide temporary air ventilation; provide over pumping and tankering; facilitate the Tunnel Inspection Contractor’s and Other Contractors with access to and egress from the tunnels by providing the lifting plant and carrier baskets at up to twenty-one project locations simultaneously.

3. Rapid response access to remove blockages: From near surface parts of the tunnel infrastructure.

When instructed by Tideway, the Contractor will be responsible for the removal of blockages from near surface civil structures (called vortex generators) at any time during the System Acceptance Period. The Contractor will provide the plant and the people that can be rapidly deployed to undertake the removal.

Further details of the Thames Tideway Tunnel Project can be found at www.tideway.london ↗.