Tottenham Court Road Crossrail Station, London

To support the delivery of a new £14.8 billion Crossrail project that aimed to transform rail transport in London – increasing capacity by 10%, cutting journey times and supporting regeneration – we constructed the foundations for the new Western Ticket Hall. 

Our scope of works included installing 39, 1,800mm diameter piles, up to 44 metres deep, to provide the foundations for both the station box and the future over-site development (OSD), as well as a 1,000mm thick, 221-metre-long diaphragm wall for the station box.  

The diaphragm wall was built using panels ranging from 2,800mm to 4,400mm in length. Geothermal loops were installed in 45 out of the 63 diaphragm wall panels, allowing us to maximise the use of sustainable energy to heat and cool the building. This was only the second time that a Geothermal system had been used within a diaphragm wall in the UK and contributed to a 20% reduction in the project’s carbon emissions. The reinforcement cage was fitted with geothermal pipes and ‘box out’ units to allow access to the geothermal system without having to drill or damage the concrete, this is crucial for connecting the pipes to the heat exchanger system. For health and safety reasons and to ensure maximum contact with the surrounding soil in order to extract geothermal energy, the geothermal pipes were installed on the outside face of the reinforcement cage. 

The project presented significant engineering challenges, requiring the installation of a diaphragm wall and rotary bored piles within a congested urban site. Located next to London’s busiest shopping street, the site faced numerous operational constraints and required detailed logistics planning to minimise disruption. However, we were able to deliver these critical foundation elements on time and within the budget.  

To verify the high quality of the diaphragm walls, our specialist in-house testing and analysis team conducted sonic testing by installing six sonic tubes on the reinforcement cages to confirm the structural integrity of the diaphragm wall panels.