The Secret $5BN Tunnel Under London

this Tunnel right here is the latest addition to London's Subterranean landscape it's 25 km long 7 m wide and cost more than5 billion US which is about £ 4.5 billion but this isn't a new rail tunnel and trust me when it's up and running you definitely do not want to go for a ride in it but it will relieve one of London's most urgent [Music] problems every year 40 million tons of raw sewage is dumped into the temps that's enough to fill Wembley Stadium 40 times over now this once in a century project is designed to change all that but there's just one thing the land under London is a complex Maze of tube blinds mail rail pipes and potentially unexploded bombs so how on Earth do you dig an enormous tunnel through all that without potentially bumping into something the UK has a sewage problem England's rivers are filled with a chemical cocktail of sewage agricultural waste and plastic since 2020 England's water firms pumped sewage into our rivers and seas for more than 7 million hours a rainwater and sewage mix for 9 months of the year across the country sewers are bursting at the seams and their contents are ending up in rivers it's turning this green and pleasant land into the color of the BBC weather map the temps is no exception in 2022 14.3 billion lers of sewage ended up in the capital's main water course London's existing Plumbing dates back to the Victorian era when engineer Joseph Basel Jetts was commissioned to create the city's first comprehensive sewer system when it opened in 1865 Basel jet sewer was a Triumph of engineering but the population of the city it was built to serve has almost tripled since then so in 2016 work began on this the temps tideway [Music] tunnel so R for people that don't know what is temp tiway what's this project about so temp's sideway tunnel is a 25 km 7.2 M internal diameter tunnel from 30 m deep in the west to about 70 M deep in the East to capture flows of sewage that currently overflows into the river temps from the old Victorian sewer Network currently when it rains in London or if there's any other kind of surge overflow pipes funnel the excess waste into the river the new super sewer works by intercepting the waste and plopping it down the deep shaft into the new tunnel where it floats away for processing we've tried to make that sound as nice as we can essentially it's a 21st century backup for this centuries old sewage system for the tunnel to work it has to stay close to Basel Jet's original system running alongside the temps for most of its route it also needs to fall consistently by 40 M over its length to allow gravity to facilitate the flow of feculent and that's the catch the ground under London is almost as congested as the space above it where' you start with digging a tunnel that big under London there's so much happening under our feet what kind of stuff do you have to think about well the planning that goes into a project like this is quite enormous so from 2007 to to 2014 7 years of of of design and planning we Transit something like 43 42 or 43 tunnels as we come our 25 km two of them are are below us in the west all the rest of them are above us once the river was mapped there was just the smallest isue of avoiding everything else this is the Victoria embankment it runs for about 2 km along the north side of the temps and it was created by Basel jet to hide his sewer before it was constructed this area where I'm standing would have been just the Muddy Banks of the river temps but it's not just the sewer that's underneath here this stretch is also shared by the circle and District underground lines there's another 10 tube lines which intersect the path of the tideway tunnel as they cross underneath the temps as well as a multitude of Road tunnels utility pipes and mail rail to name just a few so how do you avoid all of that you really like threading a needle the whole way through London well we were getting underneath it really I me here we're 5 m no our tunnel isn't but the rest of our infrastructure is about 5 m away from a couple of tube lines we very close to Bridges so we go under uh some of the most iconic bridges in London and the amount of instrumentation assessment of those structures to make sure that when the Tuttle Boring Machine passes underneath typically 50 M below the surface of the river that there's nothing un TOS going to happen in 2018 with the route set it was over to the tunnel Bor machines to start digging because of the mix of chalk and Clay under London six different tbms were used so that's a 25 km tunnel under one of the busiest cities in the world with multiple machines to align that's a lot to keep track of and the team did it by using this ezri Arc GIS we needed to be able to generate an understanding of where things were in the ground today the geology as well as the physical built environments and we needed a tool that would enable us to see that in a way that engineers and planners could interact with Arc GIS enabled the team to combine hundreds of years of data ranging from the most upto-date CAD models all the way back to Basel Jet's original blueprints this let the team create a 3D model of the entire project with millimeter accuracy that huge source of data is also used to create specific applications for the team on the ground if we were out stay um worrying about where all the doors were and we wanted to M those that's a really easy thing for us to spin up and do can go out and do a lot of condition surveys through it we capture the data in the field telecom's communications allow us to beam that straight back into our databases and push it straight back out through our web mapping front ends so effectively there's not it's almost a realtime data data from field to desk having the ability to feedback data in real time was especially valuable in some of the Project's most sensitive areas under my feet is where the river Fleet flows out into the temps but where it will soon be diverted into the new temps tiway tunnel but there's just just one problem it's directly under black Fry's bridge to get around this challenge the cver which would divert the flow into the new sewer was constructed in a coffer Dam next to the bridge but once again London's underground got in the way the ideal place to build the Coffer dam is exactly where the waterl and City Line runs under the temps and up into bank that made it impossible to build the foundations needed to keep the Coffer Dam stable meaning it had to be built even further away from the bridge once the C was constructed it then had to be floated into place before being rested on a conrete slab on the riverbed tunneling Works were completed in 2022 and the team is now testing them out before they get commissioned later in 2024 this might not be the most glamorous of projects but it's the perfect example of how infrastructure is the unsung hero of our modern lives let's up on running this system will catch all but the most extreme overflows into the temps and play a vital role in keeping the river clean and safe for the people and Wildlife who rely on it this video was sponsored by ezri you can learn more about arcgis at the link below don't forget that you can learn more about the temps tiway tunnel and other topics on our Channel over on the world's best construction podcast available right now wherever you get your podcasts and as always guys if you enjoyed this video and you want to get more from the definitive video channel for construction from the channel that takes you into some of the world's biggest sewers hit that subscribe [Music] button

Channel: The B1M

Views: 559,004

Keywords: B1M, TheB1M, Construction, architecture, engineering, The B1M, Fred Mills, building, tideway, sewer, esri, london, underground, tunneling, water, thames, tbm, blackfriars, thames tideway tunnel, infrastructure

Id: LW-Jhg0cZsk

Length: 8min 52sec (532 seconds)

Published: Wed Mar 13 2024