There are many technical challenges still facing High Speed 2 (HS2), according to the project’s engineering director.
Speaking at New Civil Engineer’s Tunnelling Summit today (7 November), HS2 project engineering director Tim Smart said that there were a number of challenges still facing the teams that will carry out the design work on the project.
“What’s important to us?” he said. “Establishing an efficient design is paramount. We need a right first-time design.”
Smart added that logistics would play a huge part in the design of the network.
“We have a lot of spoil to use and not all of it is moved out by rail, a lot of it will be used in mitigation earthworks, landscape noise works, bunds etc.,” he said.
“We are a sustainable project and we want to use as much of our waste material as we can. There are limits on it; as for a high speed rail project, there are constraints on using high grade fill but we want to use as much of it as we can.”
Smart said he wanted to see more innovation in the tunnelling sections of the scheme, using lessons learnt from the Crossrail project.
“We want to use 3D laser screening [and look at] how we can use smart analytics in instrumentation and monitoring. We won’t have as much instrumentation as on Crossrail, as most of it is in the countryside,” he explained.
Smart also said that there was a huge challenge in trying to increase the sustainability of the concrete that will be used on the project.
“There’s a challenge on the sustainability front, about using low carbon concrete,” he said. “There are a lot of environmentalists that would love to fit out the project with sustainable products. However, we do need reinforced concrete and for high speed rail to go fast, it’s heavy and they have braking forces and that does mean OPC (ordinary Portland cement). That’s an omission on the carbon front, so what we do about that is going to be an interesting challenge.”
He went on to say that there seemed to be a panacea that building information modelling (BIM) saved money, but insisted that the engineers involved with the project would have to make sure that BIM was buildable.
“I’m not sure how that works,” he said. “I’ve got examples around the world where BIM has not saved money.”
He added that there was a danger that BIM could become a thing that is run by “computer jockeys” without looking at the engineering behind it.
“I’ve seen problems in construction, because there haven’t been the experienced engineers looking at the output. There are no clashes, but can you actually build it?”
Smart also announced that all of the tenders have now been submitted by the preferred bidders and that the chosen contractors for the major civils works packages for each of the three sections on the project would be announced in summer 2017.
He said that the contract for HS2 is being carried out in a two-stage process. Stage one, he explained, will involve setting the target price and revision of the programme, and stage two will focus on honing in on the final target price. To provide an incentive, Smart said that there would be a “quite complicated” pain-gain share.
“Basically at the end of stage one, it’s 50-50 pain-gain share; and at the end of stage two, it’s 60-40 in favour of the contractor,” he said.