Underwater Tunnel Project in South Korea Documentary
Your next vacation may be spent in a paradise you’ve never heard of you’ll just need a way to get there here’s the catch that way has to go underwater it would become the deepest immersed highway on earth oh they also have to build a couple of bridges and did we mention the typhoons these talks are towing a contradiction a tunnel segment that’s both colossal and fragile maybe your slowdown a raft of techno breakthroughs and untested results bound for a place few known to entice the world to visit and even sway the choice for the Olympic Games Busan is South Korea’s second-largest city million people bigger than Madrid closing in on Milan and as hectic as Manhattan South Korea is an Asian tiger and Busan makes it raw its skyline will soon include one of the world’s tallest buildings it’s the nation’s biggest port and the fifth busiest in the world every three seconds they unload a container it’s so busy they had to build the scrolling Busan Newport and still Busan grows busan is such a comer it’s bidding for the 2020 Summer Olympics but Busan has one big problem and it’s on display here at one of Asia’s biggest fish markets dozens of vendors crammed in here 14 hours a day every day of the year and that’s the trouble with Busan it’s so crowded it’s running out of room the solution to Busan’s problem lies just across gin hey BAE go Jay an island seven times bigger than Manhattan but just one eighth of Manhattan’s population busan go Jay Busan go Jay go Jay is a goldmine of development a potential Korean Riviera with room for Olympic athletes to hit their stride and for the Korean tiger to stretch its legs but go Jay has its own big problem getting there by sea go Jay lies only eight kilometres from Busan but by Road it’s 140 kilometers three and a half hours one way one of the world’s worst commutes lost time and lost work costs almost 400 million dollars a year and it could cost Busan the Olympics the athletes won’t come if they can’t get around the solution will slash travel time from nearly half a workday to 40 minutes and revolutionised life on both sides of the bay the boo sanggojae fixed link a four-lane highway that runs nearly 50 meters beneath the sea then it leaps across two colossal cable-stayed bridges altogether longer than 80 football pitches one of the biggest infrastructure projects in the world plunging 48 meters below sea level the link will boast the deepest immersed roadway in the world the tunnel will be composed of 18 mammoth segments each as long as two football pitches and as heavy as an aircraft carrier wide enough to carry two lanes of traffic each way with an access tunnel between that’s the concrete reality now here’s where it gets dicey each segment has to be carefully towed into position then carefully sunk to the seabed and all the segments have to align within 35 millimetres less than a thumbs width whether adds its own demands this site is exposed to the open sea there are always high waves and the water is deep as well sushi Livesey it is wide open to the Northwest Pacific Ocean so we have extreme exposure conditions before the construction period so we’ve got to be ready for whatever that sends us like big swell waves say strong winds and even occasional typhoon building a tunnel like none ever seen we’ll take techniques like nah never tried yet the Koreans have never built an immersed tunnel but this country has the Dutch have five centuries of experience at holding back the sea of shrink up and finish tunnel immersion is actually a Dutch speciality if you look at a number of immerse tunnels in the world most of them are in the Netherlands don’t I’m fed up if the Meister in Natal not that’s completely new either so the Dutch company had a zest for a challenge and the confidence that they could solve these problems and so we were able to trust each other but that’s how we ended up working with the Dutch you now face a particularly this is what confidence looks like we have a look in elope of the ever me up with the forever 21 years ago Peter van Westendorf joined struct him at the bottom and worked his way up he’s worked on eight underwater tunnels better when it yeah but not as daunting as the fixed link its know about Dana line this next more is just nothing better than immersing a tunnel it’s great to work with a relatively small group of people who are so focused on their job Slager only raise and put in two hundred percent that’s just amazing construction begins with the tunnel entrances one on guard oak island the other near an uninhabited island from here engineers will dig down to 12 meters below sea level to meet up with the undersea tunnel segments but they won’t tunnel through the seabed itself if they did the gradient would be too steep for driving instead Peters crew will lay prefabricated tunnel segments on the seabed first engineers dredge a trench where the tunnel will rest to buttress the foundation they bore concrete columns into the seabed stopping 3 meters shy of bedrock the reason earthquakes avoiding bedrock will give the tunnel crucial flexibility the segments will rest on a bed of gravel to ensure an even surface because the bed determines the exact height of each tunnel segment the gravel must be placed with pinpoint accuracy later the entire tunnel will be covered with thousands of tons of crushed rocks to protect it from collisions with ships or anchors because the tunnel segments will be prefabricated the first challenge is finding land for a Construction Yard not an easy task in Busan if you look around there’s not a single meter of flat land anywhere that a contractor can use as a as a piece a for the construction period from the tunnel site the closest spot lies 35 kilometers away it’s big enough to build up to five tunnel segments at a time each segment weighs about 48,000 tons and is made of eight sub sections each twice as long as a London bus anyone with a basement knows water can penetrate concrete joints potentially disastrous in an underwater tunnel but each giant section is cast without a single joint thanks to Korean ingenuity we continuously poured fall sections from the ground up to the top of the walls to eliminate gaps in the walls a process lasting 24 hours after casting the ends are sealed with steel bulkheads a Dutch innovation best appreciated later on the bottom of Jinhae Bay the bulkheads are watertight because these babies are about to take a bath flooding the drydock will allow them to float the segments out to sea in India of about the inundation of the dog takes approximately 48 hours during the first phase we let in water until it reaches the level of the bulkhead door then we’ll check to see if the bulkheads are leaking once all the leaks are repaired or if there are no leaks we’ll fill up the dock completely it’s enough water to fill 230 Olympic pools so how do you prep 48,000 tons of deadweight to float in now inside every tunnel segment there are six ballast tanks and they’re filled with water Ben Ilyich Lepus an old British for my master pumpin mind a Bible enema to start the flotation process we begin pumping out the water we continue until the tunnel segment starts floating the grotessa do is to tow that slow then with the auto inches at the backsides we control it’s an element or sideways direction now they can begin to warp out the segment removing the first segment takes brawn and finesse to avoid colliding with the drydock I thought nothing even Debra mica with barely two meters on each side there’s no room for error grandma latest on the design the delay mr.
Chicken is over hammer oh by the bones amazing huh believe it or not clearing the dry dock was the easy part while work continues on the undersea tunnel the rest of the boo sanggojae fixed link starts to rise two giant bridges one with three pylons the other with two at its top most the two pylon bridge will saw 156 meters above sea level the height of a 50-story building the span between the pylons will stretch the length of five football pitches with enough room for the tallest freighters to pass under crucial for a city that thrives on shipping for its livelihood the most pleasing aspect of the bridge is also the most daunting it’s curved diamond shape provide a drop click opera bin of course curved pylons are very difficult to construct but they’re very much in harmony with the surrounding scenery in many ways in that they bear resemblance to a mother’s praying hands and to the wings of seagulls I think it 35 kilometres away the first five tunnel segments arrive at a temporary mooring site from here they’ll travel across Jinhae Bay to their resting place on the sea floor already leveled and lined with gravel and here’s how they’ll get their pontoons the size of a mansion Dutch designed Korean made one pontoon is positioned near each end of the tunnel segment after arrival at the tunnel site mammoth winches on pontoons will lower the segment to the seabed at least that’s the theory because it’s never been done in the open sea a specialist diving team prepares the first tunnel segment for the immersion operation divers test connections for data systems and power supplies standing by and remove marine growth from the bulkhead down on the wire placing down wire finally they install steel wires underneath the tunnel segment crucial for positioning during immersion position now we can come up on the wire coming up on the wire above water the crew are also adding a temporary access tower so workers can enter the segment in case of trouble with the ballast tanks every problem has to be anticipated because if things go south they won’t get a second chance the space look what we do doesn’t have anything to do with luck we know it’s involved we know how the process works and we have the feeling we control the whole process not quite back in Holland the rest of the immersion team stands by to fly out in all 56 men wait for Peter to say go and he’s waiting for a forecast when the wind blows from the south swells roll in from the Pacific not being an offshore because we’re situated offshore we have to deal with waves these waves will be pretty fierce even swells barely 30 centimeters high packs so much force they could fracture the subsections that form the tunnel segments throughout its journey the segments will be at the mercy of the waves so the team needs three days of calm seas struck ttan looked around for a forecaster but few dared to stick out their neck for such a costly guess then a Danish company seized the challenge they came up with a model to predict waves as small as 10 centimeters up to five days out a stunning breakthrough in forecasting the what else image that that means we’re able to say tomorrow we can do an immersion and that means we’re able to put people on the plane yesterday really on a last-minute basis it takes away a big risk for us and for our client emitter all shown the same addiction the smell still not as bad so we go green light we’ll try one more try okay thank you yes a headlight 48 hours of tension for the boss 6 months of work rides on steel threads and a forecasters guess tonight no one will sleep soundly after a cautious voyage at 3 kilometers an hour the first tunnel segment arrives a guard Oak Island the starting point of the tunnel joining Peter is the elite team fresh from Holland among the few men on the planet who can do this job boy uncle says father of boards honey Esther the monk doin all secondary bugger but working along Shore poses a huge challenge forty-eight thousand tons have to be maneuvered into a slot with just one meter of clearance underwater on each side one false move and the segment could get jammed in the rocks controlling the segments of 14 steel cables and cut in the rocks and on the seabed aligning the segment takes painstaking accuracy surveyors take readings using a system of prisms and mirrors mounted on the access shaft and the survey tower it’s all new to the Koreans so it takes time getting used to the technology the ordeal will take all day and end either with an engineering triumph or a forty-eight thousand ton disaster with so little clearance and so much at stake the segment moves at a snail’s pace after a journey of 35 kilometers it’s now just four meters from the abutment ever all fair long we’ve worked really really hard for a half a year to prepare for this moment 56 of our people are here to execute this operation the Koreans are excited intense because they’ve never witnessed this we’ve done it more often but still a very special moment till now steel plates have protected the leading edge of the segment years ago behind them is a component as crucial as it is fragile a rubber gasket to ensure a watertight connection with the abutment now they’re ready to begin the descent operated by remote control the ballast tanks slowly fill the command post monitors everything via remote control cameras on the pontoons and inside the tunnel segment okay yeah here they you tomorrow maybe 5000 feet the Hawaii about a second the segment must align with the mouth of the tunnel to within three and a half centimeters you can’t afford you can imagine that if this segment were placed 10 centimeters off and he did that 18 times you’d end up 2 meters off on the other side well that wouldn’t be very good 7 hours later touchdown the segment now rests just 50 centimeters from the abutment the mouth of the land would tunnel to close the gap engineers have installed a pair of powerful hydraulic jacks linking the jacks and applying tension closes the gap the final stage begins from the land Woodside a wall of water nearly three meters wide separates the segment from the abutment what they call the immersion joint opening this valve will force the water out as the immersion joint empties external pressure will further compress the gasket for a watertight seal the echo from the bulkhead reveals the water level in the joint with the water drained they can open the bulkhead door but the locks jammed you know that the evil sir gonna breed you know that because you made you feel the toolbox with you this calls for cruder technology all that stands between the crew and the first immersed segment is the steel wall installed back at the dark and here is why it’s so brilliantly simple another two knots engineer seal the ends of segments with concrete then lock it out after immersion but that takes time and creates debris the modular steel bulkheads are easy to install easy to remove and they’ll be reused on every segment and eventually recycled faster cheaper and safer an engineering trifecta yeah finally Open Sesame while in they will be experience some unexpected things we were very happy that it was completed successfully in the end and the feeling of accomplishment was indescribable you lot of illnesses the marathon operation lasted almost 78 hours some have gone 2 days without sleep one down 17 to go and they won’t all go smoothly like the Busan tomorrow the bridges advance in segments but two at a time not one it’s called balanced cantilever construction working outward steel segments are laid on each side of the pylon to keep the bridge in balance then two cables are attached to brace the segment’s once they’ve done that the directory and then lifts up six precast concrete panels and places them onto the steel frame then put a final post-tensioning into the cables and we’re ready then to start the whole thing over again back at the tunnel the team have installed 12 concrete segments but now they’re heading for 48 meters the deepest water and the hardest challenge my thin train’ll throws it out fast okay you stop ever actually I’ll over there are not new hurdles demand new techniques the seafloor out here is soft clay so they need to set anchors that can hold the segment and pontoons fast Stev Montes named for their fish like shape they’re designed to dig in where other anchors lose their grip once segment 13 arrives here 14 steel cables connected to the anchors will hold it in position but once again deepwater raises the stakes whilst the segment hits the bottom suppose a problem arises with the ballast tanks somehow Peter would need to get the engineers inside on segment 1 they could use an access tower but not in deepwater the solution is a first internal immersion a self-propelled diving bell purchased in America the sub was refitted just for this project coming down to 50 meters see we kept the tunnel on Sona simple element he had that’s something Metron Bochy with a little boat like this that can go to 300 meters you’ve got the concept of a ferry transferring people to the tunnel segment it’s nine meters long with room for a pilot copilot and five engineers it can dock on a landing Tower on the segment for watertight access to the tunnel you deep-water poses another problem monitoring the position of the segment as it’s lowered because one misalignment would be disastrous to calibrate the position of the first segment surveyors took readings from prisms mounted on the access tower but remember there’s no access tower here so once more the Dutch devised a smart simple solution it’s named for what it is a taut wire one end attaches to the leading edge of the segment to be immersed the other end attaches to the previous segment the taut wire ensures the connection stays under high tension positioning the device is a delicate operation this custom-made model is the only one in existence breaking it is not an option when this segment descends a computer will record the length and angle of the wire allowing the team to monitor the segments position it will rise on irritation the taut wire is now under high tension between this segment and the previous one and as the segment descends the wire automatically retracts and becomes shorter so that provides us with exact positioning data to fine-tune the position of the segment on the seabed four of these sensors are attached one on each corner of the bulkhead another custom innovation for this project and wait till you see how accurate they are the whole operation is remote controlled from the command unit on the pontoon with one click they start filling the ballast tanks we make fog you can feel the tension building up now and then we all have one question can we do it again can we get it in position it’s the same tunnel but it’s farther away from the coast it’s deeper the weather everything so many aspects make it different every time so you have to stay alert all the data feeds into Peters computer and refreshes the position of the segment every second is that there are at all this is the tunnel where we have to go to the green one is the final position and this is where it is now so you can see it’s just below sea level context is shaking it 3 over took another day on 113th on Island you chose any what’s right and a lot of bluster on data from the winches allows him to adjust the segment during this end it all happens like working downstairs one step forward one step down and the deeper it goes the more careful the steps in there’s fire surviving at this stage where the tunnel is just a few meters underwater there’s no problem we can still move in any direction nothing can hit it but when we’re approaching the segment that’s already on the bottom then I have very little clearance so the steps I make will be a lot smaller you it takes 7 hours to descend 48 meters just 9 centimeters a minute the first step in joining the segments poses another challenge and another solution the moment a tile segment approaches the one ahead of it it’s moving because of the swell so we install to guide beams on the top end of the segment book another simple but elegant solution madatha different at the moment we pulled them closer together the guide beams become less flexible the movement diminishes until the segment is motionless with only 50 centimeters separating the segments and in near zero visibility a diver connects the hydraulic jacks the segment seemed aligned yet the slightest error on this end will translate into a big mistake at the other but the Dutch don’t miss a trick the full remote-controlled sensors on the bulkhead now deploy they measure the position of the segment within one millimeter the width of a guitar string and relay the data back to the command center Peter needs to shift 48,000 tons of concrete 20 centimeters to the right even on calm days the swell is so heavy and the segment is so long stability is a problem the solution the external positioning system or EPS yet another Dutch invention based on a simple idea a pair of hydraulic legs an extendable feet to hold lift and move the segment connecting each pair of legs are four steel cables already installed back at the mooring site braced on its robot legs the EPS laterally aligns the segment into its correct position now the jacks are tightened by remote control compressing the rubber gasket done one more segment complete like the tunnel the bridges approach the final stages before the two pylon bridge can accept its last section engineers have to perform a stretching exercise as Tiny as it is powerful both pylons have to be pulled back about 7 centimeters to create enough space for the key section to be placed once the tension is released the final section will have a tight fit after six years they must be eager to finish but just like the tunnel crew they have to move in baby steps because this baby is a giant a few kilometers away Peters crew prepares to install their last segment just like the first segment number 18 has to be maneuvered between rocks as before they run some of the anchor lines from the pontoons to the rocks somehow or I get there because it’s so close to the island it’s very difficult to install the immersion connecting them isn’t easy by any means it’s not just a matter of simply pulling them in place with all cables attached they can start maneuvering the segment into place you can take our because this segment is extremely heavy we can’t afford even a small mistake light contact can cause huge damage to the segment and that kind of damage can set back the entire project after three years they’ll open the last tunnel segment tonight if all goes well the segment hits the bottom but there’s trouble one end is sitting 28 centimeters too high now trying to figure out the bosses we don’t know yet it’s a major a problem with enough you’re taking about half an hour go all through all the steps so that we don’t miss anything then I’ll inform you the gravel foundation under one of the EPS feet is overbilled so they’ll have to remove the foot and the ground opening we’ll have to wait one more day after final adjustments the last tunnel segment now sits squarely on the sea floor all that’s left is entering the tunnel to seal the joint with the final segment they’ll enter via the tunnel entrance and God opened it’s the last time Peter will make this trip between their town there they are later you start something three years ago the first time you think gee still so many to go but time flies now it’s the last one that feels kind of strange mixed feelings glad it’s almost finished but it’s a pity we can’t do one more we’re approaching that moment again it’s at the bottom opening the door hoping it’ll all be okay after three years light at the end of the tunnel the clip had a new open sanke the last step is pumping water out of the immersion joint so the segment can close up for a tight seal Monisha faith they have ever been a development tal as a fiddle blade ok prema they always celebrate their stand but today is the grand finale once complete strangers now firm friends and soon to go their own way the end of their long journey lies behind this bulkhead door and the honor of opening it falls to Peter back at the bridge the final section is lifted into place once the tension on the towers is released the whole structure will be locked in place with the bridge complete all that remains is opening the final segment of the tunnel last inspection two thoughts really extremely proud that we did it and happy of course happy for the whole team it’s just great after all this time and after a difficult operation we did it very emotional yes fits the moment I’m proud so so proud yeah come back for Peters team the tunnel marks another success on a stellar resume for the Koreans it’s a chance to join the Dutch on the world stage actually this was the first the most color project in Korea and we developed lots of new equipment and we trained the last surviving the engineers and you can terrific for the finish in time and everything is happy this isn’t just a shortcut to an island it’s a path to the future …
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