Hanson Regen provides soil solution for super sewer

Ground granulated blast-furnace slag product used to overcome difficult ground on Thames Tideway Tunnel project

HANSON’s Regen ground granulated blast-furnace slag (ggbs) has been used to overcome difficult ground conditions on part of the Thames Tideway Tunnel super sewer project at King Edward Memorial Park Foreshore in Wapping, London.

Around 5,700 tonnes of Regen, supplied from the company’s Purfleet plant, in Essex, has been used with 3,000 tonnes of Ketton cement to create a binder to stabilize soil so work to construct a combined sewer overflow could progress and provide a connection to the main east tunnel.

Together with Costain, Vinci Construction Grands Projets and Bachy Soletanche, Hanson were involved in extensive lab trials to test the performance of the system and suitability of the selected mix design.

The company supported the mix trials with materials and technical advice, which led to a binder being chosen for the works. Deep soil mixing – a technique that enhances the characteristics of weak soils by combining them with a cementitious binder – was chosen as the final stabilization method.

Robin Styles, Hanson Cement’s technical development manager, said: ‘Due to the variability of the soils on the site, it was imperative to find the right mix. Regen was used in the cement blend due to its superior resistance to aggressive ground conditions, as well as its ability to reduce the carbon footprint of the soil-mixing operation through its low embodied CO2.

‘As a leading supplier of ggbs, and with capabilities to supply the project, we were delighted to be involved in the works, which were completed successfully.’

The Thames Tideway sewer network expansion is due for completion in 2024 and is taking place across 24 construction sites in London, from Acton in the West to Beckton in the East.