Minimisation of spoil to landfill from a collaborative approach to re-use on site

The High Speed Two (HS2) affordability challenge launched in November 2018 was the springboard to new ideas to change the scheme in the West Ruislip area. The idea was named the NEMO concept (New Excavated Material Opportunities). NEMO achieves a 3% carbon reduction, avoids 400k m³ of excavated material and removes 1.35M m³ of off-site disposal, with significant cost, programme, community and environmental benefits.

The idea works by replacing a large cutting with a cut and cover tunnel, reinstating the countryside over this tunnel to return to the local community, a shortening of the West Ruislip Portal to shorten the critical path of the tunnelling, and reconfiguring existing rail sidings at West Ruislip for use during the construction. This eliminated the need for an even larger temporary railhead at Copthall Cutting, which was the basis of the hybrid bill design.

As shown in this paper, a holistic approach to the design has led to a combination of ideas coming together to achieve one big idea that delivers more than the individual parts. This paper explains the full story of NEMO, as well as all the benefits it will deliver once fully implemented.