Thames Tideway Tunnel, London
Thames Tideway Tunnel, London
Client: Costain, Vinci Grand Projets & Bachy Soletanche Joint Venture (CVB JV)
Project: Thames Tideway Tunnel East Section
Value: Wentworth fee £7m, overall project £4.5bn
Client: Costain, Vinci Grand Projets & Bachy Soletanche Joint Venture (CVB JV)
Project: Thames Tideway Tunnel East Section
Value: Wentworth fee £7m, overall project £4.5bn
Upgrading London's 150-year-old sewage system required a new 25km tunnel running beneath the Thames from west to east, called The Thames Tideway Tunnel. Wentworth worked on the East Section, where tunnel depths reached 70 metres and ground conditions varied from London Clay to water-bearing sands and Chalk. We provided continuous geotechnical and temporary works support across six major sites, assessing existing Thames Water structures and underground assets while designing complex temporary works for a project of this magnitude.
Upgrading London's 150-year-old sewage system required a new 25km tunnel running beneath the Thames from west to east, called The Thames Tideway Tunnel. Wentworth worked on the East Section, where tunnel depths reached 70 metres and ground conditions varied from London Clay to water-bearing sands and Chalk. We provided continuous geotechnical and temporary works support across six major sites, assessing existing Thames Water structures and underground assets while designing complex temporary works for a project of this magnitude.
700
700kPa of hydrostatic pressure to provide additional isolation
700kPa of hydrostatic pressure to provide additional isolation
600
tonne tunnel boring machine to support components
tonne tunnel boring machine to support components
10
year appointment across the life of the full programme
year appointment across the life of the full programme
Our role
Our roleWe supported the Costain Vinci Bachy Joint Venture (CVB JV) design and construction teams from early stages through project completion. Our work spanned multiple sites, including Abbey Mills Pumping Station, Chambers Wharf, Deptford Church Street, Earl Pumping Station, Greenwich Pumping Station, and King Edward Memorial Park Foreshore. We developed 3D finite element geotechnical models, designed temporary foundations and support systems, assessed impacts on existing Victorian infrastructure, and provided rapid response engineering support as site conditions and construction sequences evolved throughout the 10-year programme.
We supported the Costain Vinci Bachy Joint Venture (CVB JV) design and construction teams from early stages through project completion. Our work spanned multiple sites, including Abbey Mills Pumping Station, Chambers Wharf, Deptford Church Street, Earl Pumping Station, Greenwich Pumping Station, and King Edward Memorial Park Foreshore. We developed 3D finite element geotechnical models, designed temporary foundations and support systems, assessed impacts on existing Victorian infrastructure, and provided rapid response engineering support as site conditions and construction sequences evolved throughout the 10-year programme.
Capabilities
Capabilities- Infrastructure
- Substructure
- Geotechnics
- Structural Engineering
- Temporary Works
- Infrastructure
- Substructure
- Geotechnics
- Structural Engineering
- Temporary Works
- Long-term partnership: continuous involvement from early design through construction completion, built deep project knowledge
- Risk management: 3D geotechnical modelling identified and resolved potential issues before construction, preventing costly site delays
- Heritage protection: Victorian structures remained operational and undamaged throughout complex adjacent works
- Construction confidence: bespoke temporary works designs tailored to each site's specific conditions enabled safe, efficient delivery
- Collaborative approach: open communication and proactive problem-solving with the CVB JV, other designers, contractors and stakeholders resolved complex multi-party challenges.
- Long-term partnership: continuous involvement from early design through construction completion, built deep project knowledge
- Risk management: 3D geotechnical modelling identified and resolved potential issues before construction, preventing costly site delays
- Heritage protection: Victorian structures remained operational and undamaged throughout complex adjacent works
- Construction confidence: bespoke temporary works designs tailored to each site's specific conditions enabled safe, efficient delivery
- Collaborative approach: open communication and proactive problem-solving with the CVB JV, other designers, contractors and stakeholders resolved complex multi-party challenges.
Designing infrastructure for 600-tonne TBMs
Designing infrastructure for 600-tonne TBMsGreenwich Pumping Station and Chambers Wharf required temporary foundation systems to support tunnel boring machine delivery, storage, and removal operations.
Wentworth developed a full 3D FE geotechnical model to verify the global stability of the existing cofferdam, considering loading effects exerted by the TBM shield and cradle delivery, the long-term storage of TBM gantries as well as due to the extraction of spud legs of jack-up barges.
We created shallow and piled foundation schemes accommodating loads from steel structures, overhead bridge cranes, and the skidding system for tunnel boring machine delivery and removal.
At Greenwich, to protect an adjacent historic river wall while handling TBM components up to 600 tonnes, we developed a temporary foundation system for large slurry treatment silo farms and equipment. This included a ground-bearing slab and a sheet pile wall to protect the historic river wall. Emergency tanks for the de-sanding units were designed to meet strict liquid-tightness and serviceability requirements. Shallow foundations supported a temporary shed structure with two overhead bridge cranes, facilitating the delivery of TBM components up to 600 tonnes using SPMTs and specialised gantry cranes.
Wentworth developed a full 3D FE geotechnical model to verify the global stability of the existing cofferdam, considering loading effects exerted by the TBM shield and cradle delivery, the long-term storage of TBM gantries as well as due to the extraction of spud legs of jack-up barges.
We created shallow and piled foundation schemes accommodating loads from steel structures, overhead bridge cranes, and the skidding system for tunnel boring machine delivery and removal.
At Greenwich, to protect an adjacent historic river wall while handling TBM components up to 600 tonnes, we developed a temporary foundation system for large slurry treatment silo farms and equipment. This included a ground-bearing slab and a sheet pile wall to protect the historic river wall. Emergency tanks for the de-sanding units were designed to meet strict liquid-tightness and serviceability requirements. Shallow foundations supported a temporary shed structure with two overhead bridge cranes, facilitating the delivery of TBM components up to 600 tonnes using SPMTs and specialised gantry cranes.
Greenwich Pumping Station and Chambers Wharf required temporary foundation systems to support tunnel boring machine delivery, storage, and removal operations.
Wentworth developed a full 3D FE geotechnical model to verify the global stability of the existing cofferdam, considering loading effects exerted by the TBM shield and cradle delivery, the long-term storage of TBM gantries as well as due to the extraction of spud legs of jack-up barges.
We created shallow and piled foundation schemes accommodating loads from steel structures, overhead bridge cranes, and the skidding system for tunnel boring machine delivery and removal.
At Greenwich, to protect an adjacent historic river wall while handling TBM components up to 600 tonnes, we developed a temporary foundation system for large slurry treatment silo farms and equipment. This included a ground-bearing slab and a sheet pile wall to protect the historic river wall. Emergency tanks for the de-sanding units were designed to meet strict liquid-tightness and serviceability requirements. Shallow foundations supported a temporary shed structure with two overhead bridge cranes, facilitating the delivery of TBM components up to 600 tonnes using SPMTs and specialised gantry cranes.
Wentworth developed a full 3D FE geotechnical model to verify the global stability of the existing cofferdam, considering loading effects exerted by the TBM shield and cradle delivery, the long-term storage of TBM gantries as well as due to the extraction of spud legs of jack-up barges.
We created shallow and piled foundation schemes accommodating loads from steel structures, overhead bridge cranes, and the skidding system for tunnel boring machine delivery and removal.
At Greenwich, to protect an adjacent historic river wall while handling TBM components up to 600 tonnes, we developed a temporary foundation system for large slurry treatment silo farms and equipment. This included a ground-bearing slab and a sheet pile wall to protect the historic river wall. Emergency tanks for the de-sanding units were designed to meet strict liquid-tightness and serviceability requirements. Shallow foundations supported a temporary shed structure with two overhead bridge cranes, facilitating the delivery of TBM components up to 600 tonnes using SPMTs and specialised gantry cranes.
Managing extreme loading conditions for 70m shafts
Managing extreme loading conditions for 70m shaftsAt Abbey Mills, we faced the challenge of delivering a massive roof cover slab via self-propelled modular transporters (SPMTs) over 70-metre deep shafts. The existing structure had initial prestressing and cracking that needed careful assessment. We developed a 3D finite element (3D FE) geotechnical model that analysed soil-structure interaction and assessed adverse effects from the planned roof installation sequence. This is the heaviest plant loading adjacent to the shaft in the world.
At Abbey Mills, we faced the challenge of delivering a massive roof cover slab via self-propelled modular transporters (SPMTs) over 70-metre deep shafts. The existing structure had initial prestressing and cracking that needed careful assessment. We developed a 3D finite element (3D FE) geotechnical model that analysed soil-structure interaction and assessed adverse effects from the planned roof installation sequence. This is the heaviest plant loading adjacent to the shaft in the world.
Designing temporary bulkhead resisting 700kPA
Designing temporary bulkhead resisting 700kPAWentworth also designed a temporary reinforced concrete bulkhead resisting 700kPa of hydrostatic pressure to provide additional isolation to the existing concrete plug between the Lee Tunnel and Thames Tideway Tunnels. This 3D FE analysis enabled permanent works construction within the shafts to proceed with confidence that existing structures would remain stable under extreme loading.
Wentworth also designed a temporary reinforced concrete bulkhead resisting 700kPa of hydrostatic pressure to provide additional isolation to the existing concrete plug between the Lee Tunnel and Thames Tideway Tunnels. This 3D FE analysis enabled permanent works construction within the shafts to proceed with confidence that existing structures would remain stable under extreme loading.
Protecting Victorian infrastructure
Protecting Victorian infrastructureAt Deptford Church Street, we had to maintain the operational capacity of a Victorian sewer while the main tunnel was under construction. The existing masonry structure couldn't be disrupted, but capacity enhancement was essential. We designed a steel flume to fit precisely within the Victorian sewer, with flexible bulkheads accommodating differential thermal expansion between the new steel and the existing masonry while maintaining structural integrity and waterproofing.
At Earl Pumping Station, Thames Water assets sat within the zone of influence of deep soil mixing, secant pile walls, and jet grouting operations. Our detailed 3D geotechnical assessment evaluated potential damage from permanent works and the construction of the combined sewer overflow chamber, allowing us to design propping schemes that protected existing assets throughout excavation.
At Earl Pumping Station, Thames Water assets sat within the zone of influence of deep soil mixing, secant pile walls, and jet grouting operations. Our detailed 3D geotechnical assessment evaluated potential damage from permanent works and the construction of the combined sewer overflow chamber, allowing us to design propping schemes that protected existing assets throughout excavation.
At Deptford Church Street, we had to maintain the operational capacity of a Victorian sewer while the main tunnel was under construction. The existing masonry structure couldn't be disrupted, but capacity enhancement was essential. We designed a steel flume to fit precisely within the Victorian sewer, with flexible bulkheads accommodating differential thermal expansion between the new steel and the existing masonry while maintaining structural integrity and waterproofing.
At Earl Pumping Station, Thames Water assets sat within the zone of influence of deep soil mixing, secant pile walls, and jet grouting operations. Our detailed 3D geotechnical assessment evaluated potential damage from permanent works and the construction of the combined sewer overflow chamber, allowing us to design propping schemes that protected existing assets throughout excavation.
At Earl Pumping Station, Thames Water assets sat within the zone of influence of deep soil mixing, secant pile walls, and jet grouting operations. Our detailed 3D geotechnical assessment evaluated potential damage from permanent works and the construction of the combined sewer overflow chamber, allowing us to design propping schemes that protected existing assets throughout excavation.
OUTCOMES
OUTCOMESThis project demonstrates the value of sustained early involvement across a major programme. Our 10-year engagement with the project gave us a thorough understanding of each site's history, allowing us to integrate solutions and take advantage of existing features rather than work around them.
Key results:
The Thames Tideway Tunnel East Section was completed successfully in 2025 after 10 years of construction, with Wentworth's construction engineering knowledge helping deliver predictable outcomes across some of London's most challenging underground construction sites.
Key results:
The Thames Tideway Tunnel East Section was completed successfully in 2025 after 10 years of construction, with Wentworth's construction engineering knowledge helping deliver predictable outcomes across some of London's most challenging underground construction sites.
This project demonstrates the value of sustained early involvement across a major programme. Our 10-year engagement with the project gave us a thorough understanding of each site's history, allowing us to integrate solutions and take advantage of existing features rather than work around them.
Key results:
The Thames Tideway Tunnel East Section was completed successfully in 2025 after 10 years of construction, with Wentworth's construction engineering knowledge helping deliver predictable outcomes across some of London's most challenging underground construction sites.
Key results:
The Thames Tideway Tunnel East Section was completed successfully in 2025 after 10 years of construction, with Wentworth's construction engineering knowledge helping deliver predictable outcomes across some of London's most challenging underground construction sites.
“Wentworth engineers have provided continuous support to the Costain Vinci Bachy Joint Venture design and construction teams throughout all stages of the project's development. Their rigorous design processes and commitment to high standards have significantly contributed towards the project's success.”“Wentworth engineers have provided continuous support to the Costain Vinci Bachy Joint Venture design and construction teams throughout all stages of the project's development. Their rigorous design processes and commitment to high standards have significantly contributed towards the project's success.”
Alexandre Chaizemartin
Design and Engineering Manager
Costain Vinci Bachy Joint Venture