This project comprises a 28.5m deep basement in central London to host a Proton Beam Therapy Centre, the second of only two in the UK to be operated by the NHS, and a 5 storey 220,000ft2 Oncology and Haematology centre.

This specialist hospital is dedicated to delivering advanced cancer treatment and surgical services in London. The Proton Beam Therapy centre is housed in a 5 storey deep basement (to a maximum depth of 28.5m).

CampbellReith undertook a desk study which revealed the presence of numerous buildings and assets in close proximity to the proposed basement, including London Underground tube tunnels and fragile Victorian brick sewers, which would require impact assessments to be undertaken.

A comprehensive site investigation was undertaken to develop a detailed ground model for the site, including a specialist 50m deep borehole and small strain stress path analysis testing.

From this a non-linear finite element analysis was undertaken using a combination of WALLAP, Plaxis 2D and XDisp software packages. Various retaining wall types were modelled and the full construction sequence analysed to assess the impact on third party assets and to inform both the temporary and permanent works design. Reviews were also undertaken against published case study information and empirical data to ensure a representative and robust analysis was being carried out.

The experienced team of geologists and engineers collaborated closely with the structural team developing the design and as a result a 1m thick diaphragm wall was adopted, which offered the benefit of stiffness combined improved watertightness. This ensured that movements were limited to within acceptable limits which resulted in timely sign off of the scheme by the London Underground, Thames Water and London Borough of Camden.

The project won the UK Geotechnical Project with a Geotechnical Value of over £15m at the Ground Engineering Awards in 2018.