Megaproject: Singapore's Deep Tunnel Sewerage System | Tomorrow City | Part 1/3

Singapore is running out of space space to develop and prosper there is more development now it is harder to find land now the little red dot is being redesigned for the 21st century no one has done it before this is the only job that allows you to work on a project smart

city

in Singapore we are going from about 350 megawatts of solar energy to two gigawatts of solar energy and that is a big jump. New

megaproject

s using cutting-edge technologies will harness energy from the sun. It's kind of new For Singapore to have solar panels in automated water sports, I can't imagine that we will develop a 60 plus and go

deep

er.

I didn't believe the space saving

part

until I saw it with my own eyes. This is what engineering must find. space and allow Singapore to flourish this is a journey to Singapore's

city

of

tomorrow

it is a critical moment for one of Singapore's new mega projects one of the world's largest machines is being delivered to a site in the heart of Singapore a

tunnel

boring machine or

tunnel

boring machine today We are lifting all the main bodies to unload them on site. We do it at night because oversized cargo can only be transported after 9:30 p.m. m.

The TBM is so large that all six pieces must be delivered one at a time. The space in Singapore is a luxury both above ground and at its only landfill in Palau Samacal, which is reaching maximum capacity to create more space. A project is being carried out underground to revolutionize waste disposal and water management. The Deep Tunnel Sewer System or DTSS is one of the largest in Singapore. underground projects worth approximately 7 billion dollars this is the second phase in which 19 tbm will excavate hundreds of kilometers of underground tunnels that will carry wastewater across the island to different recovery plants to maximize the space in the

system

DTSS will be excavated

deep

er than any existing road and railway network at depths of between 35 and 55 meters this is one of the 50 shafts the entrance to the underworld a huge 10 meter wide hole known as m shaft is almost 50 meters deep depth The workplace in the m shaft is packed with construction and lifting equipment.

Supervisor Johnson and his team must now find space for these six massive

part

s. Okay, stop. Stop the cable. Space restriction is the biggest challenge for us today. 2:20 a.m. m., now we are going to move the front part of the body down 2 meters inward and then we will be. I am going to prepare the cutting head discharge area with the beams with the heavy SS and it is also the most delicate. Once all sections of the TBM are delivered and unloaded, the most important ones must be lowered one by one into the shaft and then reassembled underground.

The section of the whole tunnel boring machine is the cutting head. The cutter head has a diameter of 7.5 meters and is made up of dozens of high-strength cutting discs that chew through the rock at a speed of approximately 3 meters every hour. Behind the cutting head is the power source. The TBM is multipurpose as the cutter head bites into this section erects the walls of the tunnel which are made of these concrete rings the cutter head generates large amounts of waste or sludge and this section of the TBM is its waste removal

system

to drive The TBM's front thrust cylinders push against the newly constructed tunnel rings with a force large enough to move an elephant, the cutting head arrives.

Engineers take extra care when unloading this spaceship-like equipment, okay. , stop spinning, stop, heat, heat, the cutter blades are precisely designed. The team places wooden blocks underneath to prevent any damage to the blades. It slowly rotates counterclockwise as the engineers complete the download. The dawn is dawning. Well, thank you all. Good job. Good job. A further six weeks of preparation will be needed before the TBM sections are ready. ready to be assembled in the tunnel below the m shaft The deep tunnel sewer system is not scheduled to be completed until 2025 and is being built to last at least a century, so engineers will inspect every detail of the work during construction to making sure nothing is overlooked One of the engineers on the inspection team is Wu Lai Lin, so what are you doing in the workshop today?

I have been doing DTSS since DTSS one which was completed in 2008, so yes, we have been talking about the deep tunnel switch system or dtss for many years, when the dtss is completed, 300 hectares of land will be released above ground, more than half of which are currently occupied by pumping stations and recovery plants. The 19 giant tunnel boring machines still have 100 kilometers of tunnels to build. DTSS 2 follows the much used Aya Raja Highway so that all TBMs work underground. 50 vertical wells have to be drilled along the highway route without disrupting traffic, so the first thing we do is watch the long wells sink the launch wells and then we would launch the tvms from these wells and then the tvms will move forward happily, hopefully, until we reach the recovery pit, which is where we take out the machines.

The observation pits along the Ayah Raja Highway are a challenge. Space is definitely one of the challenges we can encounter. space on the surface to locate our boreholes or, more importantly, to place a large enough rack where we can launch our tunnel boring machines. There is more development, now it is more difficult to find land for your wells and things like that on the lower delta highway, a new piece. of machinery is changing the way wells are built and saving space at the same time, it is called vertical axis sinking machine or vsm. I didn't believe in the space saving part until I saw it with my own eyes.

It allows the construction of a well without the need for men to be inside the well digging, in fact, you can use it in very narrow places, very close to existing buildings. Site engineer guo hao is here to check the progress. One well has already been built and another is under construction, so this well is approximately 10 meters wide in diameter and approximately 50 meters thick. How is the parallel program? Everything is going well today they are going to finish the connecting bridge on the website, so after that we will fill with water. Okay, initial situation according to what we are currently using.

It is the only VSM machine in Asia as it is a relatively new concept compared to a traditional excavation method. The system works like this: first a narrow pit is dug to a depth of about 10 meters, then it is lined with prefabricated concrete rings and now the pit is ready. For the VSM, which has a telescopic arm with a head that can rotate to dig deep, engineers must carefully calibrate the robot arm before putting it to work. So how the vsm works is that there is a cutter drum for this ratty drum to move. towards the axis in and out in and out like the arms are going to rotate, okay?

The VSM is doing vertically what the TBM or tunnel boring machine is doing horizontally underground as soon as the cutter drum excavates a full 100 millimeter circle in both the shaft and shaft. The cutter drum will move down. It takes at least 10 hours to dig one meter as the ground sinks. Engineers will insert concrete rings that form the wall of the well. Okay, stop checking. Well, please measure the lens. Okay, ready, that's it. Thank you so much. It is the last time engineers can enter the pit. Once the telescopic arm is calibrated, the opening will be filled with water for the machine to begin the excavation work.

This is what engineering is all about, it is where we find solutions to reduce risk to workers. And to really improve excavation efficiency, the VSM system allows excavators to do their work in tight urban sites like the Lower Delta Highway on the highway, but underground engineers will soon face the biggest challenge in all of geology. Singapore underground that Singapore planners are spending. billions of dollars to build a new waste disposal system, the huge DTSS tunnel boring machines are working deep in our city down here, the biggest problem for engineers is geology, the hidden world beneath our feet, so between where I am now and maybe Right behind the camera, the ground conditions can differ a lot, so it is difficult for a TBM to cater to different types of ground conditions that change so quickly.

Adam Switzer is a geologist at the Singapore Earth Observatory. He has spent many years studying geology. of

singapore

and understand the challenges faced by tunnel diggers tanjong rimao is one of the few places locally where the hidden world beneath is exposed these rocks were deposited millions of years ago and over time have been twisted and folded by movements The geology of western Singapore is like that, with many different types of rocks very close together and very complicated in terms of folding and small faults, which means that the engineering adds a lot of complexity, so if you look here, the rocks change a lot in a very short period of time and you have your engineering system going in a way that drills through sandstone and all of a sudden you come to a muddy shale like this, the unit here, or you run into a bed full of big rocks that we have in Singapore.

Also, their engineering will have problems and that is what is happening in the x1 well located next to the Benoit flyover along the Aya Raja Expressway. The irregular readings of the tunnel boring machine or tbm instruments have stopped the tunneling work long before we began our work, of course, there are a whole series of on-site investigations carried out, shafts sunk and all that, but You can only sing so many ball holes that are close together to get an idea of ​​the ground conditions you are encountering, so between two ball holes you can draw a line that shows you where the head of the rock is, but in I could actually go this way.

Exploratory holes were drilled here before tunneling began, although ground conditions still proved difficult for the cutter head to tunnel. Can it change to normal form? screen yes, we are at 2.9 bar yes, for engineer Christian Schilling one of the most important tasks is to maintain the cutter head as the TBM slowly advances, the cutter blades constantly wear out and the huge machine must stop periodically for maintenance and in the underground Singapore it is a complicated operation so this is an example of a mixed fish right, yes, a mixture of rock and earth and these are the rocks, yes, and we teach the earth, ah, it is very bright, I can feel this is like soy, it's much softer and then the other one.

What you actually have here is quite interesting to understand the conditions of the terrain. The engineers examine samples of the rocks excavated by the TBM and confirm that the rock wall through which they have been excavating the tunnel is composed of a mixture of hard and soft materials at the moment they have stopped the TBM to intervene the head. Chilling has to choose the right moment when the ground ahead is stable and is less likely to collapse onto the workers, the geology, let's say it is interesting so far, at more than 500 meters we had mainly soft rock now we are from about 200 meters in a soft geology, it is mainly clay, it is never a good time because of course we want to continue channeling , but at that time we have to check what is the road level and what is the ground level and based on that we prepare this place for our front map.

Alright, the TBM is digging a tunnel 50 meters below sea level and the air pressure downwards. Here it is much higher than on the surface for the team it will be like diving underwater and as divers they will have to acclimatize to the pressure. This particular one we have finished changing our disc cutters which this time were 10 pieces and now we still have some scrapers to change the soft soil tools and

tomorrow

we should be on the road again. TBM engineers can only plan ahead if they have a good idea of ​​the types of rock and soil the TBM must traverse as they move underground.

Geologist Adam Switzer and his colleagues continue to map Singapore's underground world today. They have come north to investigate the mysterious springs of Sembawang. It is an area famous for its 70 degree Celsius water source and here we place the eggs andWe left at approximately one. time maybe the thing will be served our eggs are a little liquid we put them under the jacuzzi for 20 minutes but they were good, it was a good day, yes, and it was fun to be able to cook them outside and inside water the sembawang hot springs do more than cook eggs Liquids: Provide vital clues about Singapore's underground geology Singapore is not known for earthquakes and volcanoes, so the puzzle is where all this heat comes from It is quite rare for a hot spring to occur in a spicy rock sauce, it should be shallow enough that it still reaches the surface with some heat capacity and the water comes out here at about 70 degrees, it's enough to cook eggs, so you know that means that heat surface should be reasonably close at the Singapore Earth Observatory, geophysicists are using cutting-edge technology to solve the mystery of the springs and to look deep beneath the island's surface, the hot springs are evidence of an active fault line located in somewhere deep below a fault is a fracture in the earth's crust and here it heats the groundwater that is transported to the surface in Sembawang to vaporize those springs.

Faults can also activate and cause earthquakes, but where exactly is this fault and could it pose a problem? danger for dtss tunnel diggers, so this type of instrument is actually our ears and earthquakes or any other type of seismic source are like our hands caressing the watermelon, so when this energy penetrates through the earth , carries information about the underground structure, equipment. places seismometers at locations across Singapore to record data. I would adjust the position a little. Yes, it's really working. Yes, you can take it off and that's it. Over a five-week period, seismometers record vibrations from traffic, construction and distant seismic events, the result is a digital portrait of underground Singapore that they hope will identify the location of any dangerous fault lines.

It's actually at a very high frequency, so this type of map tells us what type of frog is underneath. the ground, so these numbers represent the speed of the shared pathway traveling within the earth, we can determine where this fault line is that separates the granites in the middle and the sediments of the Jurong Formation in the west and that is really important when there is construction. underground work the team will need more time to install additional sensors to determine possible problems hanging over the tunnels with expanding built-up areas and new mega projects like the dtss the information will provide insight and help prevent disasters like the nickel highway incident in 2004 On April 20, 2004, steel supports on the MRT tunnel loop line under the six-lane Nickel Expressway collapsed.

The disaster causes a blackout and plunges traffic into chaos. Construction work on the loop line had to be stopped and the highway closed for seven months to repair the lives of four lost men. This catastrophe still serves as a haunting reminder today. Huge

megaproject

s like the DTSS are built to last until the next. The tunnel is 22nd century technology but the project depends on one of the oldest construction materials: concrete, and one of the most critical ingredients is running out. There is no limit to Singapore's ambition to build the city of tomorrow and free up space for the future.

To achieve this, the new DTSS or Deep Tunnel Sewer System is digging deep beneath Singapore creating a network of tunnels that will revolutionize waste disposal and water management. All types of waste will be treated by reducing the amount of disposable garbage and generating energy. In the process the DTSS will redefine recycling for the future and relieve pressure on Singapore's only landfill in Palau Samacal, which is reaching maximum capacity, but solving the waste problem on such a scale creates other construction projects such as the DTSS They are hungry for concrete and this demand is increasing the need for a key ingredient, sand, and sand is in short supply in Nanyang Environment and Water Research Institute researcher Den Hui believes he has found a solution.

Basically, concrete is made of cement and then our fine aggregates, like sand, and then also cost aggregates, like pebbles or larger rocks, it's the bond between cement and aggregates, like sand. That makes it strong enough to withstand high compression loads, making concrete the perfect raw material for mega projects like DTSS. Sand is mainly used in construction in river sand. The world uses almost 50 billion tons of sand every year. I don't have enough sand Ten Hue believes he has the answer to the sand shortage. Waste is convinced that waste can be the new sand and a solution to improve the quality of concrete.

Our goal is to improve the quality of concrete. We have this project with nea. We have this waste-to-energy research facility. We use very high temperature gasification to convert the waste into a very stable classification. Select a new scent. The key to the process is heating to high temperatures of 1600 degrees Celsius to be exact. This produces a gas that can be used. for power generation and slag with an unattractive name or new sand in this process very little is wasted this new sand is made of pure waste we are trying to use it to replace our sand in a higher proportion this paw is a very material new and we do I don't know many properties about this and currently ours are still doing the characterization and then to fully understand this material the big question is how does new sand compare to river sand.

We can see that the river bank is made up of a lot of sand very fine particles with occasional large particles all the sand particles are rather rounded due to natural erosion along the rivers. The consistent, rounded size of river sand particles helps them bond easily with cement, so for our new sand, Select Experience I can see a very distinct rod-shaped structure known as fiber. glass and also very angular particles. A test is being carried out to compare new sand with river sand samples, so we are doing a replacement ratio of 50, so the design mix will be 4kg. of cement and then we make um 2 kg of sand and 2 kg of slag, so we will put the cement and the fine aggregate in the mixer and then we will start the mixing process.

Your sample will now undergo a compression test to see how much load or weight it can hold before cracking, it starts with the typical cube of concrete, so in the lab we test how much load it can hold through the machine. of compression, we keep applying increasing compressive strength on the concrete and then we see the maximum load it can withstand before it cracks or before it fails we can see that as the strength increases, the strain increases very quickly The next ten tests tone the new sand concrete. The higher the number, the more load or weight the concrete cube can bear. to overcome is 82.4, but in our new sand concrete you can see that as the strength increases in the initial stage there is very little deformation and the winner is Nussan.

The superior strength of the new sand has to do with these rod-shaped structures that join with the cement and with proven theory, this new sand concrete will soon be ready to be tested in reality in the ports of civil engineers. have reached a critical stage in the dtss project. The preparations in the m pit have been completed and it is time to lower the six different parts. of one of the largest TBMs, also known as tunnel boring machines, into the finished borehole, it is very difficult, the whole process will take at least two weeks. Well, that means we'll be dropping the rigger after 1:00 p.m. m., very good, so one of the milestones is to complete the assembly of the tunnel boring machine so that we can continue with the next step, which is the underground mining work.

Engineers begin connecting the different sections of the tunnel boring machine. The completed pieces are pushed into a pre-dug opening to make room for the next piece and then it comes. In the second stage, these gantries will house the electrical supplies for the control cabin and the train tracks to transport the tunnel segments. As soon as the TBM has penetrated about 100 meters into the rock, the remaining gantries will be lowered into the shaft when completed, the machine will be 130 meters. meters long, the length of 10 buses, this is one of the largest TBMs so far in Singapore, so it was necessary to segment it into a lower part at the top to make sure the alignment is correct and everything is sealed properly during assembly.

It is necessary to pay attention that all these seals remain in place. Senior project manager Uli is another veteran of tunnel construction. Today he has come to the Portstown road site to ensure that assembly goes ahead as planned. It doesn't take long for eagle-eyed Oolie to discover something is wrong. I went down to the shaft and inspected the tightness of the bolts in the state and informed the main contractor that the boats are not tight, we cannot cope with it with a cut-off wheel installation, the TBM is Apply support pressure at all times to the phase The tunnel prevents it from collapsing, so if the bolts are not tightened correctly there will be a leak through the machine segment.

The only solution is to work all night to tighten the bolts 280. The next morning, Uli returns to the site to find out if the problem has been resolved, apparently what the situation is. Yes, we are ready, so now we are placing all the cables on the drum. Yes, we are making sure that all the cables fit well in the front. Okay, so we'll be ready to connect when the cutter wheel is just a meter above the crater, we'll slide the front body forward to prevent damage to the rotating coupling. This is the cutting wheel, the largest and heaviest section of the tbm's size and weight explains why uli is so cautious.

We moved the tvm to the rear so that there is a large enough gap to attach the cutting wheel in front of the dbm. However, the complicated process of lowering the cutting wheel is now getting very tight. You can start 50 meters to the bottom of the hole and it is a very tight fit. 500 yes, it is very tight. We have to make sure it doesn't rock and it works. If any part of the million-dollar TBM is damaged, the consequences in terms of repair costs and delays. It would be catastrophic when the operation begins, everyone is hands on.

There is only a five centimeter gap between the cutting wheel and the axle wall. The swivel coupling was actually bumping into a shield on top, but we managed to leave enough room to attach the cutting wheel. After two hours, the TBM section reaches the bottom of the hole safely. One day late, the engineers are relieved. The hardest part is over and the cutting wheel can now be attached to the front body. Going underground is an important solution to Singapore's shrinking land space. The new urban plan in Punggol, northeast Singapore, will demonstrate that putting transport links underground is a way of returning city streets to the people who use them.

Space is at a premium in Singapore to create more surface space. Projects are going underground, but urban planners. They have come up with another way to tackle the problem and it is simple to plan cities in advance to maximize space, that is the concept behind the smart city and the first in Singapore is Pongol where a new district was planned from scratch led by Gilbert Chur . designed a digital district scheduled for completion in 2024, comprising a business park and a university campus, an environment where business professionals, academics, students and their families can call home, so the Pongo Drill district, together with some other districts in Singapore, are one of the ideas. of decentralization to maximize space for people planners made a crucial decision all transport links are being built underground from the new mrt connector to huge car parks leaving the ground level free for pedestrians and cyclists, I can tell you it's my angle model's favorite when If you look at this model, it's actually down here, facing west.

You see the main street, which is actually Campus Boulevard. In fact, you can see how the business park and the campers are really tied together into a very cohesive hole, so this is theset. spacewalk concept where we seek to have the deepest academic industry collaboration and that's not all room service in the beating heart of the smart district in Pongol is a new software that is being developed by James Tan and his team. It's called an open digital platform. allows them to test intelligent systems and real-world scenarios. By zooming out virtually, they can see details of the construction progress.

Yes, this is what we call a digital twin. The reason we do this is so we can have a good spatial view of what is happening. In the real world, especially when all this sensor data comes in in real time, no one has done it before. This is the only job that allows you to work on a smart city project in Singapore. The idea behind the open digital platform is to integrate smart systems with in everyday life, at some point we will need to integrate with the pdd meeting room system, if no one is using the room, we should do a reality check to know that the meeting room is at zero in this view.

I don't have one shot, like where's the one? overcrowding, so what we hope to achieve is greater efficiency through energy savings and, of course, labor distribution. On the other hand, we want to make people's lives easier, in fact, we were cleaning up the idea of ​​giving people 27 hours instead of 24 hours because I think they can save three hours of each day with less waiting time, enter faster to your office, leaving the office, etc., while the digital team builds the smart services two meters underground, another team spearheads the physical construction of the Pongol digital district, yes. Any ideas on the concourse level?

The entire Shopjimmy estate in preparation for tunnel works that will connect the digital district to the transport network. We are already reaching B1. We aim to complete it one month after the MRT roof is completed, but this is a temporary slab, so we are closely monitoring this construction sequence. Project engineer Wing Zu has been working on this from the beginning since 2017. We are working for the virtual tunnel event, which is a big milestone for the collaboration of gtc and lte. We are doing well, but of course. all the consumer projects are effective, I call it apt, but we are catching up and she is in charge of preparing the basement jobs, so now the machine is behind, how far are we okay?

The giant tunnel boring machine or tunnel boring machine that has eaten up more than 700 meters of the ground of the existing northeast MRT line is about to break through right here. One of the key challenges is that we're going under a live lrt that appears in a vaidar, so obviously we tend to do a bit more posturing. Hey, we're going very Close Make sure we don't affect the LRT structure when a TBM tunnels near critical areas underground. There is maximum alert for the entire team throughout the project. These critical points are known as zones of influence.

The challenge is to actually monitor the instruments on the TBM. be careful so that we do not dig too much and cause sinkholes the results will be very disastrous at the benoit flyover the team is on high alert two tunnel boring machines are digging tunnels very close to the flyover the two huge tunnel boring machines working together can destabilize the overpass so Engineers continually monitor the structure for any signs of weakness, so monitoring is extremely important. All of our monitoring data is collected on this online platform so you can access it at any time, so let's say you're getting readings that maybe give you over agreement.

You will be alerted, please note that our tunnel is approaching the highway. Any anomalies or significant changes, please highlight to your Engineer, we are here below the overpass where it is considered one of the critical structures for the project, so throughout this area we have installed three sets of instruments for each of the TBMs, so this will be monitored during mining work, the risk is that as the tunnel boring machines advance underground the soil above the tunnels becomes compacted causing a depression to form on the surface and in the worst case it becomes a sinkhole in densely populated Singapore this would be catastrophic this is a bare area and in Singapore most of our areas are quite congested so either you are under a road that you know, if not your other sheet, some kind of services and everything, these instruments They are part of a vital early warning system if something is wrong, the sensor readings are closely monitored with their decade of experience.

Christian Schilling keeps an eye on the progress, the TBM is constantly moving forward when we are digging a tunnel, everything is fine here, good, stay until now, there are no warnings from the sensors on the surface, so basically we see from the system reconnaissance the real position of the tunnel boring machine, we have our navigation. screen that shows us where we are currently how far we are from the alignment finally the tvms pass the critical risk zone and the next tunnel ring can be built in pongo after passing the vital lrt pillars the last few centimeters are about to give in signaling the end of the mrt tunnel and the journey of the machine, everyone comes together for this momentous event, fantastic progress, very well coordinated and very well coordinated and planned, all thanks to you, such a good job, it is a job well done for Pongol's team the moment he sees him. the crack you know is coming next and in two minutes the whole world collapses but then you can hear all the cheers for everyone this is how we live from all the jtc and lta team we finally do it we have done it dtss 2 still four years away to be completed as Singapore reaches for the sky, building gleaming towers of glass and steel deep within its depths. 19 giant machines continue to excavate a network of tunnels that extends over 100 kilometers.

This will transform the way Singapore manages water and waste, propelling the state into the next century and building a new pillar of Singapore's city of tomorrow.