Tunnel technology RijnlandRoute: a report from the heart of the operation

Central to the RijnlandRoute will be the N434, the future connection between the A4 and the A44 near Leiden. Almost 2.5 kilometers of the N434 will consist of a bored tunnel. The tender for the realization of the tunnel was won by the COMOL5 combination, in which the companies Croonwolter&dros, Mobilis, Vinci and Dimco joined forces.

The province of South Holland awarded this part of the RijnlandRoute project to COMOL5 under EMVI (Economically Most Advantageous Tender). COMOL5 promised to make everything IFAT (Integral Fabrication Acceptance Test) two years before opening. Meanwhile, the group is working feverishly in a specially created test center, in Eindhoven. GWW magazine had the unique opportunity to take a look there.

Welcome to the world of tomorrow
The old halls where COMOL5 is housed fit into the streetscape of Eindhoven's old neighborhood. On the outside, nothing suggests what goes on inside. The greater the surprise when we are let in by Jan Witte, project manager at Croonwolter&dros and assistant project manager within COMOL5. A totally different world, brimming with technology and innovation. As we recover from the amazement, Witte begins to explain, "In this test facility in Eindhoven, we are building modular units for all the technical components for the tunnel. The advantage is that we can carry out our tests here fully conditioned. All aspects involved in technical work are within walking distance of each other. We build, simulate, test, solve problems and finally arrive at ready-to-use modules that will soon go to the tunnel plug and play.       

Problems we encounter can be addressed immediately and very efficiently. This will soon prevent failure costs, loss of time and other unpleasant surprises. An additional advantage is that the number of interfaces with Civil Construction has been significantly reduced."

Simulation of the tunnel entrance. Traffic light, matrix sign and LED fixture.

Work is literally being done in the future
"An extraordinary sensation, to be able to virtually drive through the tunnel already," Witte outlines. "Everything is in our integral 3D model/ BIM. Even more exceptional is the fact that the test site in Eindhoven is already remotely linked to the traffic control center in Rhoon. The tunnel will soon be operated from there, but for them the tunnel already exists, so to speak. We currently have a live connection with Rhoon, there has already been audio contact. Bear in mind that the tunnel boring machine won't start drilling the first tunnel tube in Leiden until July of this year. People are literally working in the future here."

This is what the unit for local control looks like.

The test center is a stone's throw from the Eindhoven Croonwolter&dros office. Is that a coincidence? "Not a coincidence," Witte replies. "That's where our Technical Automation department is located. It's very pleasant to work so close together. Short distances, both internally and externally, contribute substantially to an efficient workflow."

It all started with a sketch
Witte smiles when he shares an anecdote with us: "The idea for modular construction in the preliminary phase literally started as a sketch. The fact that that same sketch, in elaborate form, won us the TBI Innovation Award in 2017 makes me cherish that image. It makes us realize that we have gold in our hands with this method, within the organization the method is now also an accepted formula within other disciplines." The construction drawings adorning the wall in the test center show nicely how everything is to be realized later. In total, COMOL5 is building no less than 24 technical modules, which will be divided between the service buildings East and West, on either side of the tunnel. The tunnel itself will also contain modules for various technical aspects. "Legolization" is a fancy word for the method of working. All parts are delivered plug and play in Leiden, it's just a matter of connecting cables. If something does not work after connection, we know for sure for 99% that it must be due to the cabling, because everything leaves Eindhoven working."

Test setup emergency phones/intercom.

Packed with innovation
The lineup of technical ingenuity is impressive. From the whole long row of working CCTV cameras, ICT network, to the complete collection of working emergency phones/intercoms, from a complete field of fire detectors linked to the BMI (fire alarm system) to the SOS (speed underrun system) linked to the MTM (motorway traffic management), everything is present and working. There is no shortage of innovation: everything is also dedicated to sustainability. "A great development is the Solar Optic Fiber sunlight system. With GPS-controlled lenses on the tunnel that rotate with the sun, light is bundled and transported via fiber optics up to 100 meters to daylight fixtures located in the tunnel entrances. This dramatically reduces the energy used to illuminate the mouths of the tunnel. That light is needed to minimize the transition between the tunnel and the outside world for the motorist's eyes," Witte explained.

Artist Impression of service building East.

Second half of 2020 is scheduled for delivery of the first modules. "In terms of dimensions, the units are specially developed to dimensions of 3 x 3 x 9 meters. This is the maximum size allowed as normal transport by road. However, we are currently looking at the possibilities of transporting them by water, for sustainability reasons. That would contribute enormously to the CO₂-reduction mean," Witte said.