The boring process
From the top of the Damrak all the way down to Scheldeplein, the route of the Noord/Zuidlijn will be excavated by two tunnel-boring machines. The machines will bore both tunnels with a time difference of about three months between the first and the second.
In the route chosen for the Noord/Zuidlijn, the tunnel-boring machines can follow the existing street pattern. That means that almost no buildings need to be demolished in the process.
The tunnel shafts will have a diameter of about 7 metres. They will be 3.8 km long – or 3.2 km if you don’t count the length of the platforms in the stations that the boring machines will pass through.
The tunnel-boring machine
Each tunnel-boring machine has a diameter of 7 metres and is approximately 60 metres long. Both machines will be assembled in the launching shaft – a construction pit some 20 metres deep in the water of the Damrak.
Just past Scheldestraat, the bored tunnel will end in the reception shaft – a construction pit about 15 metres deep, where the boring machine will be dismantled and removed.
The head of the tunnel-boring machine consists of a hollow steel cylinder: the shield. The shield is approximately 8 metres long. This is where the tunnel builders work. The shield protects them from both the ground and the groundwater that surround the tunnel.
In front of the shield is the cutting wheel, and behind the shield is where the segments that will make up the tunnel are put into position. The shield is open at the rear, where the completed tunnel sections appear. Each day, the tunnel-boring machine creates about eight metres of metro tunnel.
The cutting wheel at the front of the machine turns slowly, scraping through the ground layer for layer. The sand, peat or clay that the cutting wheel scrapes loose is mixed with water and immediately carried off by conveyor belt.
At the same time it scrapes away the ground, the tunnel-boring machine is also edged forward. It uses jacks to push itself off against the section of tunnel that it has already completed. As soon as the giant machine has made sufficient progress, it creates a new section of the tunnel by putting together a number of ‘tunnel segments’.
Once enough space has been bored open, the digging is stopped temporarily. A special device puts the new tunnel segments precisely into position. Each time, a total of seven segments are necessary to complete a section of tunnel wall.
Once the new tunnel segments have been pushed together tightly, the tunnel has grown a little longer. Immediately after each new section of the tunnel is finished, rails are laid that can carry a train loaded with workers and materials to that point.
There needs to be sufficient space for inserting the tunnel segments. The hole that is bored is therefore one centimetre broader than the tunnel itself. Once a new segment of tunnel has been put into place, the leftover space is filled with a mixture of sand, cement and water that will harden over time.
All of this takes place at a depth of 20 to 30 metres. No one at street level will be able to notice what is going on so deep below the surface.
Most of the route of the Noord/Zuidlijn runs beneath streets and canals, where there are no foundations. Wherever the bored tunnels come near the foundations of buildings, extra care is required.
The Beurs van Berlage building on Damrak and the ‘Industria’ building on Rokin are two buildings whose foundations lie close to the route of the new metro. In each case, the soil around their foundations is being reinforced with a mixture of water and cement. This will fortify the soil permanently. Along the entire route, foundations that were in a poor state were already reinforced during the preparatory phase.
Earlier experience with drilling tunnels through the soft Dutch soil over the past ten years was of great help during the preparation phase.
Since the Tweede Heinenoord Tunnel was bored under the Nieuwe Maas River in 1995, a variety of other traffic tunnels in the Netherlands have been built using this technique, including three for the so-called Betuweroute (the Botlek Tunnel, the Sophiaspoor Tunnel and the tunnel under the Pannerdensch Kanaal) and the Westerschelde Tunnel under the Westerschelde River.
Overview and HistoryAmsterdam is the capital of the Netherlands even though the seat of government is in the Hague. It is the most densely populated country in the world! And to be accurate, Holland only makes up part of the Kingdom of the Netherlands. There is North Holland and South Holland and the Netherlands encompasses them both, as well as some other area without.Time for some etymology! Netherlands is physical space reclaimed from the ocean, hence its name literally means "the ground below." The name Amsterdam comes from a dam in the river Amstel. The dam stood, guess where, Dam Square! Look at all those bikes, man, it just warms the quadriceps with joy.Amsterdam was first settled as a fishing village in the 12th century and grew to become a wealthy trading port, riding on the demand for diamonds and tulips. But let's not get ahead of ourselves..In the beginning there was water. As usual, the Romans came along and wanted to do some conquering, so they set up a military post at Nijmegen. Prosperity commenced growth lasting until the Frankish invasion of the 5th century brought Christianity.By the fall of Charlemagne's Empire in 814AD, the Netherlands was already one of the wealthiest places in Europe. Dutch shipping reached as far as Asia and North Africa while agriculture and commerce within the country flourished.Benevolent neighbors such as the Dukes of Burgundy and the Hapsburgs put in regular appearances in the Netherlands, playfully sending their armies to take over and introduce some fun taxation schedules. The Eighty Years War flared up over this jest and resulted in strong unification of the Dutch national identity.As of the sixteenth century the Netherlands became an independent Republic and within one hundred years they had grown to be the most powerful maritime nation of Europe. This is referred to as the Dutch Golden Age. Of course, major griping on the part of England followed, concerning naval power.The Dutch fell under French influence during the reign of Napoleon. The Kingdom of the Netherlands then included Belgium and Luxembourg, but they revolted during the 19th century, amidst rampant liberal and republican ideas on-continent.The country remained neutral during WWI but suffered dire foot shortages; during WWII it was invaded by Germany and resisted valiantly. But the industrial revolution had been good to Amsterdam and the city was positioned to proceed with fast economic growth in the post war period. Today the Netherlands, and Amsterdam, are one of the wealthiest countries in the world.Getting ThereThe Dutch national airport, Amsterdam Schiphol, is located 20km from the city. It is well-organized to meet the demands of being Europe's fourth-largest passenger airport. From Schiphol you can reach Amsterdam by taxi and train. Taxi takes about a half hour and should cost around 40 Euros. Also, an 11 Euro ticket for the shuttle bus service from the airport gets you access to 100 hotels throughout the city.The trains leave from the basement of the airport. "Schiphol" is the name of the train stop for the airport, a lovely sensible name you can easily understand. Some cities don't do such nice things with their train station naming. The direct rail link connects to the Central Station with trains every ten minutes at EUR 3.60 price. Thirty-five Euro fine for not having a valid ticket, watch out! The yellow ticket machine is your friend but carry change because it doesn't eat bills or credit cards.TransportationAlright! Now you're here, let's go for a walk! If you for some reason decide to be a total freak and drive a car here, we can't help you.Riding a bicycle is the best way to enjoy Amsterdam . Of course, you can use other moving objects such as train, tram, subway, bus and ferry to move yourself from one place to another. But we all know that bikes are the coolest so let's cut the crap. Renting a bike should cost about eight Euros per day. LOCK IT OR LOSE IT!!! triple exclamation mark.For riding the trams you need to buy a "strippenkaart" which is a paper ticket that can be stamped multiple times until there are no strips left.Metro in Amsterdam is a recent development, considering that the place is kind of, um, swampy to say the least. Construction started in 1977 and a new North/South metro line is in the works, no specific prediction of success available at time of writing.On the touristy end of transportation there's the Canal company which does boat tours and bike rentals as well as bus trips. Rent a canal hopper and go exploring the little waterways.People and CultureAmsterdam grew up with good manners. Being an international trading city required vast social networks and attendant tolerance of all cultural possibilities. This translated, over the centuries, into attracting people from all across the globe. Amsterdam is a real melting pot of 174 different cultures, with the freedom to be who you are and to say what you think, whether you're gay or straight, a squatter or a millionaire.Violent crimes are not prevalent here; pickpocketing and other petty theft is more of a threat to the average visitor.Now we can get to what all you young youths want to know -- how about the smoking? Yes, there are coffee shops where you can get hash or herb and smoke it. Yay. It's only tolerated, not legal. Everything else IS illegal so try to use your brain for thinking when you go to Amsterdam. Note that the red light district is under camera surveillance.Things to do, RecommendationsAmsterdam is a city of museums. The Dutch Master painters all have galleries and exhibits representing the work of their lives, from Rembrandt and Vermeer to van Gogh and Mondrian, and don't forget M.C. Escher and de Kooning either.For music there is the famous Concertgebouw, the acoustics of which are so phenomenal that it has been described as a musical instrument itself! And then numerous clubs and lounges with bangin' DJs as well.The usual stereotypes still apply: bring home some wooden clogs for a souvenir, take in a beer in a 'brown cafe' (so named for the nicotine stains), etc.But don't forget to get up high and have a look around! Enjoy.Text by Steve Smith.