Joint sealing with MC-Montan Injekt TR-X

The metro of the Danish capital Copenhagen and the neighbouring city of Frederiksberg, which went into operation in 2002, consists of four lines that run driverless and fully automatically. Line 4 (M4) originally connected the main station Hovedbanegård with Kongens Nytorv, the largest square in downtown Copenhagen. Back in 2012, the Danish parliament paved the way for an extension of the line that would in future lead to Orientkaj in the Nordhavn district. In March 2018, Metroselskabet, the operator of the metro, awarded the "design-and-build" project to the Tunnel JV I/S joint venture.

The project for the southern metro line is designed to take six years and includes the construction of two 4.4-kilometer-long tunnels with an internal diameter of 4.9 meters using two earth pressure-supported tunnel boring machines (TBMs) as well as the construction of five metro stations and two crossing structures. The opening is planned for 2024.

 

Convincing MC products

After a section of the metro had already been successfully sealed in 2017 with MC-Injekt GL-95 TX, MC was also involved in the new sub-project in 2020. After initial contacts with the "Mechanical Tunnelling" department at MC, a risk assessment focusing on products for tunnelling was carried out in May, which resulted in registration in the Danish database for chemical products. In December, under difficult conditions during the Corona peak phase, MC's injection experts carried out a site briefing of the products MC-Montan Injekt TR-X and MC-Injekt 2133 flex for the processors on site in Copenhagen. MC-Montan Injekt TR-X was used for the injection and sealing of the tunnel elements and support was provided by MC-Bauchemie Danmark Aps.

At the beginning of the tunnel boring, the tunnel boring machines were brought in via the Enghave Brygge station and sent in both directions. The vibrations of the machines were constantly checked via numerous control points in order to prevent building damage in the best possible way. The team subsequently achieved a Danish record of 56 m of bored tunnel in just one day. The performance was constantly optimised.

 

Segment joints sealed

A total of 5,700 segments had to be set. MC-Montan Injekt TR-X provided the elastically swelling sealing of the sealing profiles in the joints between the segments. The low-viscosity acrylate-based hydrogel for injection in rock and solid structures can even be used safely in alkaline environments and in contact with annular gap mortars thanks to its exceptional chemical resistance. Its very good injectability and controllable reaction time enable well-controllable injection paths. Furthermore, the positive test according to the UBA guideline even confirms the usability in contact with drinking water.

 

In addition, the fast-expanding, one-component injection resin MC-Injekt 2133 flex was used for the permanent sealing of cracks that occurred, and the fine filler MC-DUR 1250 TX was used for levelling the wall surfaces of the tunnel inner lining.

 

Work on the extension of the metro line is currently in full swing without any delays. From 2024 onwards, the M4 will cover the 6.5 km long track with its eight stations between the main station and Orientkaj in 12 minutes. With the extension to the Nordhavn district, the potential for the redevelopment of Copenhagen's northern harbour area, one of the largest urban renewal projects in Northern Europe, could also be further advanced at the same time.