BBV Washwood Heath- HS2

Project Highlights

Contract Value: £81.4 million

Duration: 42+ months

Outcome:

The project delivered a fully stabilised Depot Platform, comprehensive environmental remediation, and a successful 300m watercourse diversion. It also enabled the deep excavation required for the Tunnel Boring Machine launch.

The BBV Washwood Heath scheme stands as a vital enabler for the HS2 rail network—meeting stringent environmental, geotechnical, and safety standards while unlocking future construction phases.

Client | BBV (Balfour Beatty VINCI)

Project Overview

The BBV Washwood Heath project was a landmark undertaking valued at £81.4 million and delivered over a 42-month period. It involved extensive earthworks and environmental remediation in support of the HS2 high-speed rail network.

Duo Group played a key role, excavating over 1.4 million cubic metres of material—more than 1.1 million of which was cement stabilised and compacted to meet strict HS2 specifications. The team also managed the removal and treatment of contaminated and hydrocarbon-impacted soils, alongside the construction of a complex brook diversion.

Specialist excavation was carried out to prepare for the Tunnel Boring Machine’s breakthrough into Birmingham City Centre. The project was completed with the successful delivery of a fully stabilised depot platform, setting the groundwork for future HS2 infrastructure and meeting all environmental and safety standards.

Scope of Work

The BBV Washwood Heath project required a wide range of complex earthworks and environmental remediation activities in support of HS2. Duo Group was instrumental in delivering these works safely, efficiently, and to the highest standards.

Excavation & Soil Stabilisation

Duo excavated over 1.4 million cubic metres of material across the site.

Of this, 1.1 million cubic metres were cement-stabilised to meet specific engineering requirements.

A total of 1.3 million cubic metres of soil was placed and compacted in full compliance with the HS2 Earthworks Specification, ensuring a solid foundation for future infrastructure.

Obstruction Removal

The team encountered and successfully removed a variety of underground obstructions, including redundant fuel tanks, sheet piles, and concrete footings. Clearing these hazards was critical to ensuring the site was safe and construction-ready.

Contaminated Soil Remediation

One of the project’s most significant challenges was dealing with 70,000 cubic metres of hydrocarbon-contaminated soil.Duo managed this through a controlled excavation strategy, supported by a full-time watching brief to monitor environmental conditions and material handling.

Environmental & Safety Compliance

To maintain transparency and uphold regulatory standards, the Environment Agency conducted monthly inspections throughout the project. These visits helped ensure all works met strict environmental requirements while reinforcing best practices in health, safety, and sustainability.

Brook Diversion & Japanese Knotweed Mitigation

One of the most complex aspects of the project was the brook diversion.

• Duo installed 300 metres of sheet piles, ranging from 16 to 12 metres deep.
• This was followed by the placement of 139 precast concrete culvert boxes and the construction of a 300-metre in-situ concrete channel (10 metres wide, 3 metres deep).
• To support long-term water management, three in-situ headwalls were constructed.
• The team also completed the removal of Japanese Knotweed, installing a specialist root barrier system to prevent regrowth and safeguard the newly built infrastructure.

Specialist Excavation for Tunnel Boring Machine (TBM)

To prepare for one of the most critical phases of the HS2 route into Birmingham, Duo undertook a specialist deep excavation to create the Portal and Retained Cut.

This involved digging to a depth of approximately 23 metres below ground level, enabling the safe arrival and launch of the Tunnel Boring Machine (TBM) that would ultimately drive through to Birmingham City Centre.

The precision and depth of this excavation required careful planning, engineering controls, and close coordination with the BBV team to ensure safety and stability throughout the process.