HS2 Western Portal Sump Excavation | Specialist Civil Engineering Subcontractor | Rorcon
Western Portal Sump - SL4
Rorcon delivered the excavation and support works for the western portal sump at Washwood Heath, a key enabling element for the tunnel drives forming part of the HS2 programme.
The sump, approximately 55 metres long and up to 7 metres deep, had to be constructed within a constrained footprint while neighbouring civil works were progressing on an accelerated schedule.
The excavation served as a critical drainage and operational feature for the incoming TBM, which meant the works had to be delivered with precision, stability and full compliance with the project’s temporary works requirements.
The ground conditions demanded a controlled and staged excavation sequence to maintain stability and protect adjacent structures. Rorcon’s team installed the required support system, managed groundwater challenges and carried out the works in close coordination with the main contractor’s geotechnical and engineering teams. The excavation profile and tolerances had to be achieved without deviation, as any inaccurate preparation would have impacted follow-on works associated with the portal interfaces.
Throughout delivery, Rorcon maintained consistent production and adhered to the strict safety standards expected on a major infrastructure project. The team worked within a busy and congested work zone, coordinating with multiple contractors and adapting to evolving programme pressures. Despite these constraints, the sump was completed on time and within the contractual budget, providing a compliant and fully prepared structure for the subsequent portal and TBM operations.
This work formed part of the enabling sequence that allowed the TBM “Marie-Anne” to complete her breakthrough in April 2025. Rorcon’s contribution ensured that the portal area was ready for that milestone, supporting the wider tunnelling programme and demonstrating the company’s ability to deliver complex excavation works under tight constraints and demanding oversight.
The Western Portal Sump project highlights Rorcon’s competence in structural excavation, temporary works execution and integration within major project environments. It reinforces our capability to undertake specialist civils and tunnelling support packages where safety, accuracy and programme certainty are critical to success.
