Sources close to the contracting joint ventures working on the detailed design of HS2 have described the project promoter’s U-turn on the use of geotechnical baseline reports (GBRs) as “carnage”.
HS2 originally chose not to use GBRs and placed all the ground risk on the contractors, which has been blamed as one of the reasons for scheme designs coming in 50% over price.
The contractors are understood to have been instructed to start preparing GBRs by HS2 in November and are expected to complete the process by April this year. Both the timescale and the delivery of the GBRs by the contractors has drawn criticism.
Transport for London principal engineer Mike Black, who worked on the GBRs for Crossrail, confirmed to GE that it took a total of two years to agree the reports for the Crossrail for the tender process.
One engineer linked to an HS2 contractor told GE: “The have done a complete 180° and instructed us to write the GBRs. On Crossrail the GBRS were done by the client before the tender stage but here they are being done by the contract for a design and build project.
“Some would say they have seen sense but, in reality, they want to take back risk from the contractors to reduce the headline costs.”
The scope of work that the GBRs on HS2 are to cover is also reported to be challenging, as it includes the earthworks as well as the tunnelling, which is conventionally what GBRs are used for.
A source told GE: “The northern contractors are struggling to write meaningful GBR statements for earthworks as they are very dependent on workmanship and the weather, which you can’t baseline.”
GE understands that GCG associate director John Davis has been appointed by HS2 to review the contractor-led GBRs.
HS2 has so far declined on the change regarding use of GBRs but issued this statement to GE: “The first stage of our main works civils contract is focused on design development and the consideration of key engineering issues, including the detailed assessment of ground conditions before moving to construction. This includes, where appropriate, the preparation of reports setting out the findings of such assessment”.
The change in stance on GBRs is not the only change that HS2 is understood to be making on the scheme. Several sources reported that the form of contract on HS2 may also be changing from target cost to cost plus in a bid to provide the tax payer with better value.
Other option understood to be on the table is reducing the number of HS2 platforms at Euston from 13 to six, which would affect capacity, but would avoid the need for construction of the crossover cavern and help save around £1bn in costs.