I dont use twitter a whole lot, but I will make an exception here given the danger the #HS2 protestors are in and the apparent willful blindness to danger that some accounts like @Hs2Rebellion are engaging in.
#StopHS2
#BattleForEuston 1/23

In my day job, I'm a professional engineer and what I have seen coming out of the #battleforeuston fills me with dread. I fully believe there is an extremely high risk of the tunnel collapsing and it will mostly be the fault of the people within it. #hs2 2/23

The signs have been there for a long time in previous newspaper/vid reports. The writing has (forgive me) been on the wall for multiple reasons where the #battleforeuston protestors should have recognised they were in danger and not proceeded. #hs2 3/23

The first (and dominant) of these reasons is the soil itself, where its been described as loose, sandy and easy to dig. This should indicate immediately that the soil is *not* capable of bearing the load of the soil above it. 4/23

A common theme through many reports on the tunnel is mentioning where the tunnel had collapses during construction or during rain - another sign that the soil and drainage in situ is not stable enough to support tunneling. #hs2 #battleforeuston 5/23

Another common theme through reports is how the tunnel was inspired by The Great Escape. Now its been at least a decade since I read the book, but I *do* remember details like the POWs having massive problems with cave ins because the soil at SL III #hs2 6/23

was also sandy, and that when it caved in it occupied more volume loose than compacted - an obvious problem in the confines of a tunnel. It also, IIRC, mentions needing continuous boxed shoring - which the #battleforeuston guys havent done. 7/23

Which brings us to the next item - the shoring is made with stuff taken from scrapyards and skips. Theres no guarantee of its quality, which is the _worst_ thing when you're building something to keep you safe from ~5m of earth above you. #hs2 8/23

From memory a standard density of soil is something like 1.5t/m3; so 7.5 tonnes per square meter on top of the tunnel. Trusting your life to some dodgy reclaimed chipboard and wood of unknown strength against this weight is _stupid_. #hs2 9/23

Much was made by #larch in a recent video from @XRebellionUK on youtube of the bailiffs covering protestor shoring with their own in the shaft. But if they removed the shoring, they would collapse the shaft. Very heads I win tails you lose. #hs2 10/23

Another point is preventing ingress of water and its removal which was apparently completely overlooked. Its _sand_. Its porous. This should not be a surprise that rain has to go somewhere under gravity and the tunnel is that somewhere. #battleforeuston 11/23

Doubly so when every book ever made on constructing tunnels or mines _will_ have a section describing the importance of removing water from the tunnel or mine in question. 12/23

Yet another point is also fresh air. The Great Escapees had a sophisticated air pump with one-way distribution system to blow fresh air to the working face through pipes made from food tins and bad air back to the shaft to exhaust it. #hs2 12/23

Apparently the problem of CO2 buildup in the tunnel when occupied with protestors was never thought of.

Ironic.

Again, proper ventilation an issue in any book about tunnels or mines. #battleforeuston 13/23

Finally & maybe most damning, the regulatory knowledge of the protestors is dodgy. I noted in the @XRebellionUK @ 12:48 a graphic that shows a 30m and 100m exclusion zone for heavy machinery around the tunnel entrance #battleforeuston #hs2 14/23

#Larch makes a great point of arguing with the bailiff dude about being in breach of the regulation - but as far as I know (admittedly not my particular field of engineering) there is no such regulation for an exc zone when excavating #hs2 15/23

AFAIK HSE advice/regs require excav. to be made with shoring to an appropriate level (AKA, Not shit chipboard you got from a scrapyard) with proper baulks of timber and beefy steel prop supports. #battleforeuston 16/23

The closest I can find is in HSE HSG150 Part 276 - but no distances are mentioned. Also note Part 338 onwards same document and check this against what #battleforeuston have done. 17/23

But what I did find - with suspiciously relevant phrasing and numbers - is this document (advice only!) from Scot Nat about protecting _badger setts_ by keeping vehicles 30m/100m away _in sandy soil_ #battleforeuston

https://www.nature.scot/sites/default/files/2017-10/A2293028%20-%20Species%20Planning%20Advice%20Project%20-%20Badger.pdf

18/23

If they are relying on this document as their guidance and regulatory shield, they are putting themselves at (not hyperbole) _FATAL_ risk through their own incompetence #battleforeuston #hs2 19/23

Anyone who is in a position to do so should be trying to persuade them to leave the tunnel for their own safety. It is not a safe undertaking and they do not have the experience or knowledge to make it safe. @H_S_E does. #hs2 20/23

They may not intend to martyr themselves but I think they are blind to the risks of where they are and now stand a good chance of doing just that. There will be other protests to fight but those will not happen if they are buried alive. #hs2 21/23

Sorry for taking so long and I would not have gone on otherwise, but after being blocked by @Hs2Rebellion for asking if the Scot Nat document was what they were using, or to provide the document ref, they refused and blocked without answering. #hs2 22/23

Engineering regulation is generally written in blood. Excavations are no exception. Dont make the next lines be written as a result of #battleforeuston.

Ends. 23/23

@guardiannews @Independent @BBCNews @SkyNews @XRebellionUK