HS2 Manchester leg scrapped: what should happen now?

[Xenophon PCDGS]

While underground railways through cities do entail a lot of disruption during construction, it is usually accepted elsewhere.

With regards to the "lot of disruption during construction" part of your posting, remember that the Manchester city centre core has already had its share of such stated "disruption during construction" in recent years. Many will remember the Manchester Metrolink cross-city works that saw both Cross Street and Corporation Street taken out of road usage for such a long period of time.

 

[Nottingham59]

Does the peat rest on bedrock?

There's a layer of clays over the sandstone bedrock. I'm sure the people who built the Shell Oil refinery on Carrington Moss, or the more recent Carrington Spur Road, can tell you how thick the clay layer is.

 

[The Planner]

There's a layer of clays over the sandstone bedrock. I'm sure the people who built the Shell Oil refinery on Carrington Moss, or the more recent Carrington Spur Road, can tell you how thick the clay layer is.

Got a phone number?

 

[HSTEd]

The peat on Carrington Moss is between 17 and 20 feet. Not all that deep at all.

From "HS2 Cost and Risk Model Report" 2012, a single-bore high speed tunnel costs £45-66,000/m which is four to five times what a 12.6m wide viaduct costs (£13,000/m). And you need two tunnels.

That's not what it says.

The tunnel cost is per route metre for two options, one is a twin track, single bore tunnel (9.8m) and the other is for a pair of two single track tunnels (7.25m)

Current costs at that time were ~£32,400-66,000/m for a route metres worth of tunnel.
The viaduct cost (£13,500/m) is also for heights up to 10m tall, which would basically put it on the surface in the bog. You will need at least 5.03m of clearance under viaducts for any roads you cross.

At which point you need to pay for a lot of road/utility reroutings etc.

 

[Xenophon PCDGS]

There's a layer of clays over the sandstone bedrock. I'm sure the people who built the Shell Oil refinery on Carrington Moss, or the more recent Carrington Spur Road, can tell you how thick the clay layer is.

With regards to the underlying Sherwood Group (formerly known as Bunter) sandstone, many years ago, I was told that the depth of that in the western side of Manchester was between 530 to 590 metres. What is that type of sandstone like as a strata through with stable tunneling cold take place and are there any known aquifers in the area in question?

 

[Nottingham59]

Got a phone number?

British Geological Survey 0115 9363100

https://api.bgs.ac.uk/sobi-scans/v1/borehole/scans/items/802743

https://api.bgs.ac.uk/sobi-scans/v1/borehole/scans/items/802699

Link shows scans of 1945 and 1967 borehole records taken from British Geological Survey Borehole records database.
Logs shows coarse grained sandstone at 15ft and red sandstone at 29ft 6in
Taken from https://mapapps2.bgs.ac.uk/geoindex/home.html