Acciona Mostostal Warszawa is part of the Acciona Capital Group.

TBM Machine "Karpatka" begins tunneling in Babica

11 July 2024

The TBM machine "Karpatka" has commenced the tunneling process in Babica on July 11, 2024, as part of the construction of the S19 expressway section between Rzeszów Południe and Babica. The project involves boring a tunnel over 2 km long using the TBM (tunnel boring machine) named "Karpatka." The investment is being carried out by a consortium of Mostostal Warszawa and Acciona Construcción.

I am pleased to confirm that after adapting the TBM machine for potential methane conditions, the tunneling process has started and is safe - says Jorge Calabuig Ferre, Vice President of Mostostal Warszawa.

- I would like to thank the entire Mostostal Warszawa and Acciona Construcción team working on the project, the General Directorate for National Roads and Motorways, scientists, and experts for their professionalism and efforts to get the TBM machine ready for tunneling - he adds.

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Tunnel and TBM

The 2255-meter-long tunnel will consist of two lanes connected by 15 cross passages and an additional emergency passage. Each lane will have two traffic lanes and an emergency lane. The technology, know-how, and tunneling machine for the S19 Rzeszów Południe-Babica section have been provided by Acciona, a strategic partner of Mostostal Warszawa.

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The production of tunnel lining elements, known as tubings, takes place in a prefabrication hall directly at the construction site in Lutoryż, where a future Motorway Service Area (MOP Lutoryż) will be located. The hall is equipped with a production line, four cranes (the largest with a lifting capacity of 60 tons), and a concrete plant. Tubings form a cylindrical tunnel lining made of reinforced concrete. Ten connected tubings create a ring, and over 2230 rings will be used for the tunnel lining in Babica.

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"Karpatka" is 114 meters long and 15.16 meters in diameter, weighing 4400 tons. It has a hydro-electric drive and 12 engines, each with a power of 1 megawatt. The 440-ton cutting ring rotates at up to 2 revolutions per minute and has 471 drilling tools. The machine will tunnel more than 100 meters below the Grochowiczna hilltop. The time required to drill one lane of the tunnel is approximately 9 months under favorable conditions. The machine will then be turned around in three months and will begin drilling the second lane of the tunnel.

Detection of Methane

In July 2023, during test pumping to lower the water table for TBM tunneling, gas was detected. The gas appeared in 2 of the 44 well holes.

To ensure the safety of construction personnel, the contractor halted test pumping and drilling of the remaining wells. Methane was confirmed in the gas samples collected, and laboratory tests also confirmed its presence in the water. It's important to note that gas detection did not stop construction work on the rest of the 10-kilometer section.

A team of specialists from the contractor and investor, along with experts from the AGH University of Science and Technology in Krakow, the Higher Mining Authority in Katowice, and the District Mining Office in Krosno, worked on addressing the issue.

To prepare the TBM for methane conditions, experts in mining required the installation of methane detection sensors and a modified, high-efficiency ventilation system to prevent methane accumulation. Parts of the machine were also replaced with equipment suitable for methane conditions.

These measures comply with the EU ATEX directive, which requires protective equipment and systems for use in potentially explosive atmospheres, ensuring devices and machines operating in such conditions have appropriate safety features, especially intrinsic safety.

The tunneling process follows geological and mining law regulations. The contractor developed a tunneling project for methane hazard conditions, which received a positive opinion from the Commission for Hazards in Mining Plants at the Higher Mining Authority in Katowice. The necessary documentation was approved by the Director of the District Mining Office in Krosno in April this year, giving formal approval to prepare for tunneling.

Obtaining administrative decisions, equipping the TBM machine, and successful tests allowed the start of Karpatka's operation.

Construction of S19 Rzeszów Południe–Babica

The project is being carried out by a consortium of Mostostal Warszawa and Acciona Construcción. The contract, worth approximately 2.2 billion PLN, was signed in July 2020, and construction began in April 2022.

The project includes the construction of the Babica junction near the intersection of DK19 with DW988, and various engineering structures, including a 2.3 km tunnel, six viaducts, two overpasses over S19, a grade-separated crossing over the railway line on DK19, three animal crossings, and an underpass under S19.

Additionally, the first Tunnel Management Center in the Podkarpackie Voivodeship will be built. The investment also includes the construction of two Motorway Service Areas (MOP): MOP Lutoryż (Rzeszów and Barwinek directions) and two helicopter landing pads for the Air Ambulance Service (at MOP Lutoryż in the Rzeszów direction and at the Tunnel Management Center).

Currently, the contractor is working on all aspects, including road, bridge, and tunnel construction. Roadwork progress is at 57%, including earthworks and laying structural layers on the main route and additional roads. Bridgework is 76% complete, with the most advanced work on viaducts in Racławówka, Mogielnica, and Lutoryż, where the superstructures have been completed. Work is ongoing on installing equipment in these structures. The south portal of the tunnel is 100% complete, and the north portal is 80% complete. Production of prefabricated tunnel lining segments continues.

Overall project progress is currently around 40%.

Photo: MW