Procurement for the major civils contracts for HS2 is expected to begin at the end of this month (September 2015).

Major bored and cut-and-cover tunnels for HS2 Phase 1 London–Birmingham

Alistair Cowan, for HS2, told TunnelTalk: “Pre-qualification questionnaires for £6.4 billion of civils contracts, divided into seven packages ranging from £700m to £1bn, will be sent out later this month.”

The procurement timeline now envisages invitations to tender in Spring 2016, followed by the award of contracts later in 2016 or early 2017. This will be timed to follow the granting of Royal Assent for the hybrid bill that is currently proceeding through UK Parliament. Construction of the major civils, including tunnelling is scheduled to begin in 2018.

It is understood that the originally-planned three contracts in the South section have been merged into two larger lots, and it is these that incorporate most of the twin running TBM-bored tunnels for the first phase of HS2.

These include the 7km tunnel out of Euston Station, the 14km Northolt tunnel in the east of the capital, and the 16km Chiltern tunnel from the M25 through Buckinghamshire.

Chiltern tunnel extended again

Following a detailed engineering and environmental impact assessment, the Chiltern tunnel is now extended at its northern end by 2.6km, to just beyond South Heath. Originally it was planned as separate tunnels of 1.25km and 9.5km, but in 2012 it was decided to join them into a continuous deep level tunnel of 13.4km. Following a residents’ campaign to extend the tunnel – backed by the local Member of Parliament – the UK Government confirmed the decision to amend the alignment on Friday last week (28 August).

“HS2 is determined to keep the environmental impact of the project as small as possible and we recognise the importance of listening to stakeholders and local communities as we continue to develop the scheme,” said Alison Munro, HS2 Managing Director of Development. “Major infrastructure projects like HS2 will always be about striking a balance between engineering, cost and environmental impacts. We will remain open to potential design improvements and I believe today’s proposals would deliver a successful long-term solution for South Heath, Hyde Heath, Great Missenden and the wider area.

Most of the large civil contractors in Europe have teamed up into eight joint ventures to bid for HS2 Phase 1 civil construction contracts. These include the confirmed partnerships of Kier/Carillion/Eiffage, and Robert McAlpine/Buoygues/Volker Fitzpatrick. Costain/Skanska are also thought to have teamed up following their successful collaboration on Crossrail.

Ten TBMs will be procured for excavation of the 39km of twin running tunnels that are required for Phase 1 of the High Speed 2 Rail project connecting London and Birmingham in the UK. Additionally 16km of cut-and-cover and green tunnels will be required for a total underground alignment of nearly 25% of the total 230km distance.

In response to questions posed by TunnelTalk, HS2 Ltd has, for the first time, revealed details of the plan of attack for construction of the five sections of underground alignment that are included in the first phase of underground works. Two machines will drive the 7km x 7.55m i.d. Euston Tunnel between the route’s southern terminus at a redeveloped Euston Station, and Old Oak Common Station – both in London. The concrete segmental lining is anticipated within the current design at between 350–450mm, for a TBM outer shield diameter for the Euston Tunnel of 8.25-8.45m.

The four remaining sections of TBM driven tunnels are designed to a larger i.d. of 8.8m, and will require eight machines of 9.5–9.7m diameter.

At a supply chain briefing attended by TunnelTalk in Manchester last week (23 October), it was announced that the civil construction packages for Phase 1 are to be split into three areas:

• North (Birmingham and Curzon Street and Birmingham Interchange stations)
• Central (Birmingham interchange–Chilterns Tunnel north portal)
• South (Chilterns Tunnel/Colne Valley viaduct, Northolt Tunnels and Euston Tunnel).

Each of these, with a construction contract value of £3 billion for a total of £9 billion, is subdivided into three lots – although it is yet to be decided whether construction of Curzon Street and Birmingham Interchange stations in Birmingham will be offered as two lots or a single one. Euston Station in London is a separate lot, though at this stage, and to save money, it has been decided that a direct underground link with HS1 for onward travel to continental Europe at nearby St Pancras International will not be progressed.

The five lots that incorporate TBM driven tunnels (S1, S2, S3, N1 and C1) are in Tranche 1, with the remaining civil packages in Tranche 2.

The three southern civils packages (S1, S2 and S3) predominantly involve tunnel construction, though the S3 Chiltern Tunnel contract includes construction of the Colne Valley viaduct (Table 1). Each lot will have a contract value of approximately £1 billion, in line with the preference stated to HS2 Ltd by both the tunnelling and surface rail construction industries (Table 1).

Alistair Cowan for HS2 Ltd told TunnelTalk: “A total of 10 TBMs are envisaged. Two will drive from Old Oak Common to Euston; four will drive the Northolt tunnels – two driving west from the Victoria Road box and two east from the West Ruislip portal. Two TBMs will drive the Chilterns Tunnel, both machines driving north from the southern portal adjacent to the M25 highway. A single TBM is envisaged for the Long Itchington Tunnel, driving from the south portal; and a further TBM is envisaged for Bromford [in central Birmingham] driving from the western Washwood Heath portal.”

The Northolt tunnels package also includes a 320m SCL section between Old Oak Common Station and the Victoria Road box. A total of 11 shafts are included in the design of the tunnels in the three southern packages, each to an average depth of 35m. For the Euston Tunnel these are located at Salisbury Road, Alexander Road and Adelaide Road; for the Northolt tunnels they are located at Westgate Road, Green Park Way, Mandaville Road and South Ruislip; and for the Chiltern Tunnel they are located in the villages/towns of Chalfront St Peter, Chalfont St Giles, Amersham and Little Missenden.

HS2 Phase 1 and 2, with connections

Beth West, HS2 Ltd Commercial Director, told TunnelTalk that a series of Category Event days will be held in the new year (2015), and that these will start with the underground and tunnel construction industry in order to engage early interest and collaboration with this sector. RFQ questionaires will be sent out to interested parties in the latter part of 2015, she said. Contract awards are expected in 2016.

At this stage it has not been decided whether contractors, either alone or in joint venture, will be allowed to hold more than one construction contract. “Tranche 1 includes five large packages which encompass the bored tunnels, with each package valued at around £500 million to £1 billion. We intend to prequalify contractors for this whole tranche and subsequently issue an invitation to tender for each individual package,” said West.

“At the end of the tender process, we will award the contract to the team with the best people, the highest levels of safety, the right collaborative culture and the ability to deliver value for money. We will be appointing an integrated contractor and designer team under an incentivised two-stage contract.

“In Stage 1, the contractor will have three main tasks; first, they will develop and optimise the design in a way that’s aligned to HS2’s objectives; second, they will plan the construction, developing and incorporating opportunities for innovation, off-site manufacture and engaging the supply chain; and third, they will develop a target price which offers the best value and is deliverable.

Left to right: HS2 executives Alistair Kirk (Programme and Strategy Director), Simon Kirby (CEO) and Beth West (Commerical Director) answer questions posed by Manchester conference host Nadine Derezan

“At the end of Stage 1, the contract is theirs to lose. Often, in similar types of contracts, under-performance is tolerated because it is too difficult to reprocure - usually because of time constraints. This will not be the case on HS2. We will measure our contractors’ performance and assess the target cost. If the performance has been sub-optimal or the target cost is too high, we will seek to reprocure. We will design reprocurement mechanisms that can be deployed easily so that we have them if we need them, but our strong preference is that we never need them and never use them. In Stage 2, we want the contractor to complete the detailed design and construct the works.”

West added that the awards will be staggered, and that the Chilterns Tunnel lot is likely to be one of the last ones made because it is currently the subject of fierce criticism from protestors who want the whole section through the natural beauty spot run underground. This lot is considered a risk by the project owner, and one which can be mitigated by delaying its construction procurement.

“We don’t want to go too far down the design path while Phase 1 is still before Parliament,” said West. “We have a design of our own but as far as tunnel construction is concerned, it needs to go further. There are fewer owner design constraints on tunnelling than for other sectors to encourage design innovation and capture industry know-how.”