ABSTRACT
The Thames Tideway Tunnel project is the largest UK water infrastructure initiative since 1989’s privatisation. This summary explores the West contract’s construction challenges and innovative solutions, particularly the cast in-situ concrete secondary lining. Managed by BAM Nuttall, Morgan Sindall, and Balfour Beatty Joint Venture (BMB), the West contract includes a 7km segmental lining tunnel and a sprayed concrete lining connection tunnel. A section of the 8.5m diameter connection tunnel combines steel fibre-reinforced precast segments from the Central Contract and a cast in-situ secondary lining from the West Contract without waterproofing. To optimize construction without sacrificing integrity, BMB consulted Ramboll, using advanced PLAXIS 3D numerical modelling to simulate the secondary lining’s behaviour. Results showed a three to four days optimal construction window post-previous ring completion, ensuring cracks remained under 0.3mm. This case study highlights the role of advanced modelling in improving construction efficiency and maintaining structural integrity in large-scale projects.
