What an insight!!

http://www.skyscraperlife.com/turkish-infrastructure-technology/770-marmaray-worlds-biggest-transportation-project.html

http://en.wikipedia.org/wiki/Marmaray



First in Turkish:

http://www.ntvmsnbc.com/news/416993.asp

Treasure dig threatens Bosphorus rail link

It's been called the project of the century: a mission to connect two continents with a $2.6bn rail-tunnel running deep beneath the Bosphorus Straits.

The idea of linking the two sides of Istanbul underwater was first dreamt of by Sultan Abdul Mecit 150 years ago.


Now that Ottoman dream is finally being realised.

But the modern version of that vision has hit a historical stumbling block.

Istanbul archaeologists have uncovered a 4th-Century port at the site where engineers plan to build a 21st-Century railway hub. The Marmaray project cannot even begin work in the area until excavations are complete.

Out in the middle of the Straits, marine engineers are now working day and night to compensate in advance for any delays. Boring beneath the waves, they are preparing the ground for the deepest tunnel of its kind.

"We are strengthening the soil by injecting concrete into the seabed so we can place the tubes easily and take measures to counter earthquakes in the area," an engineer explains, shouting above the din of an enormous drill working non-stop behind him.


"It's true I lose sleep over this. I worry we won't make it on time"
Haluk Ozman, Marmaray Project Manager

Parts of the Marmaray tunnel will eventually run just 6km (3.7 miles) from the active North Anatolian fault line.

"This is the best way to link the European and Asian sides of Istanbul. There is no space for a third bridge," he argues.

The Istanbul authorities hope the Marmaray project will ease congestion in a sprawling and increasingly overcrowded city. The rail link should carry well over a million passengers a day, significantly reducing boat traffic on the Bosphorus and car congestion on land.

But the railway was supposed to be running by 2010. Now its managers are not so sure.

Ancient port

Yenikapi on the European side of the city was selected to house a state-of-the-art train station. But when shanty homes were cleared from the site, archaeologists uncovered treasures beneath of a kind never before discovered here.

Just a few metres below ground, they found an ancient port of Constantinople - named in historical records as the Eleutherios harbour, one of the busiest of Byzantium.

"We've found 43m of the pier so far," chief archaeologist Metin Gokcay explains, pointing to a line of wooden stakes emerging from a green pool of water. He says the Marmaray site has yielded the most exciting finds of his long career.

"We believe there used to be a platform on those sticks - down there is where the horses were unloaded."

"We've also found lots of things that tell us about the daily life of the city in the 4th Century," Mr Gokcay enthuses, standing close to a tunnel he suspects was an ancient escape route.

"We found leather sandals, for example, with strings through the toes and around a thousand candle-holders and hairbrushes. I've done many digs in Istanbul, but there are many things here I've never seen before."

As well as the stone remains of the harbour itself, Mr Gokcay and his team have uncovered perfectly preserved ancient anchors and lengths of rope. Dozens of men are still scrubbing the mud of centuries from hundreds of crates of artefacts, for assessment.

But perhaps the site's most treasured find is stored beneath a large protective tent.

Inside, dozens of jets spray water to preserve a wooden boat that is more 1,000 years old. Its base, about 10m long, was discovered intact beneath what was once the sea.

The dig has uncovered eight boats in total - another first for Istanbul - and archaeologists believe there are more to come.

It's a dream discovery for them, but a nightmare for the Marmaray management.

"It's true I lose sleep over this. I worry we won't make it on time," admits Marmaray Project Manager Haluk Ozmen. He says the dig is only delaying work at the Yenikapi site for now, but warns it will soon affect the entire project.

"The dig is the only thing that can delay the Marmaray project. That's why we're working 24 hours a day to meet our deadline. Everything is in the hands of the archaeologists now."

Engrossed in their task, those archaeologists refuse to be rushed by commercial concerns. Their work was scheduled to finish four months ago, but they now reject all talk of deadlines.

"The Marmaray team cannot spread their cement or tunnel any deeper here until we finish," states a determined Mr Gokcay. "They have to wait for us. And I will continue my work here until the last artefact made by human hands is found. It's impossible to accept anything else."

In addition to the Eleutherios harbour, the dig teams have exposed a long section of the city wall from the days of Constantine I - the first time the wall has ever been uncovered.

At a site as rich as this, there's no telling what else could turn up.
BBC news, two yrs. ago

Incredible!
http://www.skyscrapercity.com/showthread.php?t=504351

The Marmaray Project will dramatically improve the environment in the city of Istanbul. It is a fact that the capacity of the Project to move people from one place to another will be ten to twelve times as high as the capacity of one bridge crossing the Istanbul Strait. This means that the increasing problems related to road congestion in the old city can be reduced, as can the increasingly adverse effects on the environment of Istanbul.


There are many old houses of historical value in Istanbul. The Marmaray Project has been planned in such a way that only a very limited number of houses will be affected by the construction works. In each case, a preservation plan will be prepared and the house will either be protected, moved to another position or a replica will be constructed.
However, during construction of the Project, it will not be possible to avoid affecting some of the old historical buildings, nor will it be possible to avoid undertaking some deep excavations for the new stations


http://www.marmaray.com/html/gen_historical.html

Istanbul, Sunken tunnels, sunken boats
The bridge between the continents is now being strengthened. A massive engineering adventure called the Marmaray Project is underway. It aims to connect Asia and Europe by rail - and revitalize Istanbul's transport system. But the currents of water and history are getting in the way. The World's Alex Gallafent reports.

A city can't grow if it can't move. And on that count, Istanbul is failing. Turkey's largest city is choked by traffic. Most people get around by car. The few who use public transportation rely on a small network of trams and buses, plus a minimal subway. There's also a fleet of ferries.

The ferries lug Istanbullites up and down the Bosphorus Strait that runs between Asia and Europe. The old boats are a bit like elephants. Hard-working. Kind of cute. But also pretty slow.

To speed things up, the city's building an underwater railway tunnel. When it's completed, the physical connection between Europe and Asia will be transformed. And at least one engineering record will be broken.

“It will be the deepest immersed tunnel in the world.”

That's Husein Balkaya, one of the Turkish engineers leading the Marmaray Project. An immersed tunnel is quite a production. First you prefabricate sections of the tunnel on land. Then you dig an enormous trench in the sea bed. After that, you heave the sealed tunnel sections out onto the water and lower them down into the trench. It's how part of San Francisco's BART subway network was built.


“For the time being the deepest one is the BART tunnel in the States - it's 42 meters deep. This immersed tunnel will be 58 meters deep.”

That's about 190 feet down. The challenge of precisely placing eleven steel-and-concrete sections weighing 18,000 tons in an underwater trench 190 feet deep is pretty daunting. But the waters themselves are challenging too.

The Bosphorus Strait is a major route for commercial shipping and for the city's ferries. And, says Husein Balkaya, there's as much activity below the waves as there is on the surface.

“There is an upper current that is from the Black Sea to the Marmara Sea. And we have a lower current which is from the Marmara Sea to the Black Sea.”

These stratified currents reach speeds of up to 5 knots.

“So to immerse the elements of the deepest immersed tunnel in a stratified current atmosphere is a really big engineering job.”

The man for that job is Japanese engineer Hideki Sakaeda. On this project he's Mr. Tunnel. He strides across the construction site at Ayrilikcesme on the Asian side of Istanbul, decked out in an orange safety jacket and a hard hat.

Sakaeda explains that to connect the immersed tunnel to land, more tunnels are being dug through the rock on either side.

“From here, the extra tunnels must excavate almost four kilometers towards the end of the immersion tunnel for connection.”

So a tunnel boring machine will excavate about two and a half miles underground until it eventually breaks through inside the immersed tunnel, joining the whole thing up. The machine is now digging at a rate of about forty feet per day.

The tunnel has already been dug to a length of almost 3000 feet - just over half a mile. Various systems keep the process moving along. A fat yellow tube is suspended from the ceiling of the tunnel.

“The air contamination should be avoided. Therefore we must send clean air to the people in the tunnel. So you can see here the big duct for compressed air.”

A walkway allows engineers to ride bicycles back and forth to the tunnel boring machine. And along the floor, another pipe sucks out excavated rock mixed with slurry.

But not all rocks can be discarded so quickly. In some parts of the Marmaray Project, there's treasure to be found. Engineer Husein Balkaya has learnt that wherever you stick a shovel in Istanbul, something interesting will come up.

“In the upper layer we find Ottoman findings. We take them away, and we find Byzantine findings. We remove them we find Roman findings.”

At Yenikapi, on the European side of Istanbul, a huge swathe of land is being taken apart inch by inch. Eventually it will be the city's principal new transportation hub. But right now, this site is a massive archaeological dig.

Yenikapi

Workers surveying the site discovered that this was once a Byzantine port. 27 sunken boats were unearthed here, hidden and preserved by a cocoon of sand and silt. Under a plastic tent, archaeologist Evran Turkmanolo picks at the curved remains of one of the boats.

A Byzantine sunken boat

“What we are doing here is to first document every detail of the ship in place. We always give extra importance to the 3D modeling of the ship because as you see the curvatures are perfectly preserved. And we need to have a detailed map for future reconstruction.”

After each piece of timber has been carefully mapped, its location exactly recorded, it gets removed and taken away for desalinization. Since the wood is already waterlogged, it has to be kept wet. Strung along the top of the plastic tent is a series of sprinklers.

quoting Ismail Karamut

“We can't give a deadline, because it's not a construction site. It's an excavation site - and you'll never know what's going to come out from the soil.”

The Marmaray Project was supposed to be completed in 2010. That target date has already been pushed back to 2012. But Karamut says it's possible even more sunken boats will emerge, along with other artifacts. And he's adamant that no cultural treasures will be wiped out from history just so the Marmaray Project can finish on time.

Artifacts in crates

“All of humankind must learn its past. It's important to know where you are right now - and where you're going to be. That's why we want all these archaeological facts to be available to society. When they know their past, they can direct their future.”

There is one thing about Istanbul's future we can be certain about, says engineer Husein Balkaya.

“That is the seismic atmosphere of the area. The risk of having a big scale earthquake in the Bosphorus Strait is 65% in the next 30 years. So this means that our tunnels and the structure will survive a big scale earthquake in their lifetime.”

At least, that's the hope. Tunnel supremo Hideki Saekada says the Marmaray Project hasn't run into any problems so far.

http://www.theworld.org/?

q=node/15164http://www.archaeology.org/image.php?page=0707/abstracts/jpegs/istanbul1.jpg