A few weeks ago, I jumped at a chance to descend to the bowels of the earth ... and gawk at the state-or-the-art in tunneling technology! Take a look at the map below. (You can click on the two icons and the red line.)
The map is a topographic view of part of Kuala Lumpur (KL), and parts of the neighboring states of Pahang and Negeri Sembilan. The building icon on the left is the location of our Sinaran TTDI building.
Malaysia is building a massive tunnel to bring water in from a river in Pahang state (an "inter-basin transfer," as we hydrologists say) to quench the ever-growing thirst of the greater Kuala Lumpur area. If you see all the development in the KL area, you'll see why!
When complete, the tunnel will be 44.6 km (27.7 mi) long, the 11th longest in the world. It'll also be among the world's deepest (8th deepest), with parts of the tunnel running under 1.2 km (0.75 miles) under the mountain peaks.
The approximate route of the tunnel is shown in red in the map above. The white icon along the map shows the approximate location of the tunnel boring machine (TBM) you'll see shortly.
Shimizu Corporation of Japan)! Soon after Pat and I arrived in Malaysia, we had dinner with construction engineer Takayuki Matsumoto and geologist Frank Pittard of Shimizu (pictured here). I hadn't seen this crew for 15 years! (We're all a bit older now!) At dinner, they invited me to visit their project, and I gladly accepted.
So, along with Mun-wei Leong, a Malaysian engineer who's working in San Francisco but who was in KL on vacation to attend his sister's wedding, I set out to the construction site! (Pat wanted no part of tunnels that day...) Click on the photos to see enlargements.
adit," an access tunnel to the main shaft. The floor and walls of the adit are concrete, and equipment and supplies of all kinds line the sides.
tunnel boring machines (TBMs) in this project (there are three altogether) from fabrication to deployment. Today TBM-2 is down for maintenance, so we can get pretty close.
We pile into the small utility train that will bring us down 750 meters under the mountain. Several European TBM specialists are also on the train to do the maintenance work on the machine. Other tunnel rats are also going down with us.
As the train leaves the station and proceeds downward into the shaft, I take a last look back. I look for the proverbial canary in a cage, but I see none. The giant ventilation tubes overhead must be doing their job... <fingers crossed>
On the way down, we pass gangs of tunnel rats doing maintenance work. Rails are laid on the bottom, and the floor and walls are lined with concrete. Conveyor belts, equipment of all kinds, and supplies also line the shaft. We're sweating buckets by now.
We disembark from our train and walk past all the equipment toward the cutting head, with Matsumoto-san in the lead and Mun-wei following. Note the concrete-lined walls of the shaft with utility hooks at regular intervals to carry cables and whatnot.
Things are a lot wetter as we reach the cutting head, much of which was hidden from view by a canvas sheeting. Thankfully it's still a lot cooler (if also a lot damper) here than in the shaft.
We go from one side of the TBM to the other and crawl down to see the underside of the (back of) the cutting head. Eveything is covered with rock powder and water. Matsumoto-san tells us that we're about 750 meters below the mountain range (about half a mile) at this point.
The European techs we saw earlier have gotten themselves into a tight space to adjust and repair whatever it is they are maintaining today. They, and I, are all covered with rock powder and rock dust.
Matsumoto-san and I pose for the obligatory "at-the-cutting-edge" photo at TBM #2. Note how smooth the rock behind us is. The granite formation here is very solid, and the TBM leaves a very smooth and solid shaft that, here at least, does not require immediate reinforcement by shotcrete.
As we head back to the train, we pass a crew taking what appears to be a core sample of the newly excavated granite surface. Maybe this crew works for Frank the geologist. The entire area is free of excavated material (muck), the stuff having been efficiently carted away by the 4 km-long belt conveyor system ! The whole tunnel construction system has an efficient wastewater circulation system that carries the murky water you see to the surface for treatment at the water treatment plant!
We stop by at the site control room located at the back of the TBM train. The operator here is an Indonesian fella who was with Shimizu in Indonesia --- when I was there way back then! He sees the status of all TBM operations on his monitor panels.
Now it's time to go back to the surface. We walk back to the utility train that will take us back to the adit where we started. You are looking at the "locomotive" part of the train. The train will be traveling backwards, if you will, to go up.
We board the train and start on the half-hour journey that takes us up 750 meters to the surface. As soon as we leave the air-conditioning unit of the TBM train, the shaft starts getting very hot and humid (and noisy, thanks to the train).
This time, we have an unobstructed view of the train driver. His locomotive is pushing our carriage on the way up. It's the same hot, sweaty, and noisy half-hour ride to the surface.
Bye and bye, we pull into the train station at the surface level where the adit meets the descending shaft. Matsumoto-san's pickup truck is waiting for us. Before we break for lunch, Matsumoto-san wants to show us another part of the system that's being constructed in a more traditional manner.
So our tour is done, and we head back to the waiting pickup truck. The water tunnel is being constructed in seven chunks simultaneously: three are by TBMs, and four are by the drilling-and-blasting method. Precision surveys are undertaken regularly to ensure that these separate pieces will eventually join perfectly to deliver water to the Kuala Lumpur area.
Matsumoto-san and Kawata-san will be on this job through its projected completion date in early 2014. Seeing state-of-the-art tunnel construction was awesome! And it sure was fun to see old buddies again after so many years. Thank you, fellas, for the great tour!