LODZ | MILAN | PARIS | WARSAW | ALGIERS | WASHINGTON | ROME | SUFFOLK COUNTY

The project also includes construction of two new stations, which are to be connected to each other via the tunnels to be headed. The “Łódź Polesie” station will be located in the vicinity of the Manufaktura shopping gallery, while “Łódź Śródmieście” will be in the city center.

The EPB TBM, with a boring diameter of 13.08 m, tunnels under the inner-city of Łódź, featuring a range of historic building with only a slight overburden. This demanding ground consists predominantly of abrasive, in some cases highly abrasive, sand, stretches of loam and isolated stones of differing sizes. The first stage, totaling approx. 2.7 km in length, and later to be expanded to a double-track section, starts at the just on 900 m long tunnel between the “Odolanowska” launch shaft and the “Łódź Polesie” station. This will be followed by two further sections of tunnel, of 970 m and 540 m, connecting the “Łódź Śródmieście” and the “Łódź Fabryczna” station.

TunnelTec has developed for this project an especially durable cutting tool concept to assure mastery of the demanding soil conditions, the large diameter and the long tunnel-heading sections. Particular attention has been devoted in this context to critical factors, such as precise overcut, optimized flow of material on the front of the cutterhead and minimized, homogeneous tool wear. This special tool concept, combined with cutting tools carefully tailored to the ground, have achieved a significant improvement in tool service-lives. The pleasing result: genuine cost-savings and a decisive contribution to the overall cost-effectiveness of this project.

The future Line 16 of the Grand Paris Express will access a series of suburbs in the northern and eastern parts of Greater Paris.

Lot 2 involves the construction of an 11.1 km long tunnel. The Webuild and NGE GENIE CIVIL Joint Venture entrusted with the construction of the tunnel is using for it two earth-pressure balance machines of a boring diameter of 9.86 m. The EPB tunnel-boring machine christened “Houda” has been equipped with high-quality TunnelTec tools and is drilling the northern part of this tunnel route. This begins upstream the “Aulnay” station and ends after a length of 5.8 km to the south of the future “Sevran-Livry” underground station.

For this section of line, with its difficult geology, the customers put their trust in exceptionally robust face and bucket scrapers specially developed for this project, a special copy cutter and weld-on rippers supplied by TunnelTec for the cutterhead configuration.

The AGP Metro Joint Venture commissioned for construction of the tunnels in the north-east sector selected for one of the two tunnels an earth-pressure balance shield TBM with a boring diameter of 6.30 m, christened “Maria”. This machine tunneled with total success the “Brodno” to “Trocka” section from May 2020, achieving the final breakthrough in February 2021.

A major challenge involved in this project was the tunneling of a 1,300 m long section in difficult soil conditions of sand, gravel, large boulders and, in addition, nine concrete walls through which it was also necessary to tunnel. TunnelTec developed specifically for these tunneling conditions an individual set of cutterhead equipment which comprised, in addition to disc cutters, special cutting tools in the form of rippers and scrapers. As a result, no change of cutting tools was necessary throughout the tunnel-heading operation for this 1,300 m length. And even after completion of this challenging tunneling work, it was necessary to change only a few tools. It was thus possible to restart tunneling for the final 650 m without delay. The EPB TBM again achieved the greatest success in heading this section of tunnel.

SELI Overseas was chosen by the latter as the operational contractor for tunnel construction.

From the “El-Harrach Center” station, tunneling continues for around 10 km toward the east, with the ultimate destination being the “Houari Boumedienne” station at Algiers International Airport. An earth-pressure balance machine of a boring diameter of 10.50 m is being used for tunnel heading.

For this project, TunnelTec developed and supplied a special multi-part nose-cone unit to replace the disc cutters originally installed. The TunnelTec tunneling concept also included, to enhance tool service-life, additional cutting tools for the face and gauge areas, while special protection elements on the cutterhead rim protect the cutterhead structure.

Due to the character of the ground expected, the Webuild Group Joint Venture was anticipating elevated tool wear for the final approx. 3.2 km of the total of 8.2 km length of the Northeast Boundary Tunnel. TunnelTec developed, specifically for the conditions anticipated, cutting tools with an extended lifetime, in order to counter the higher wear expected for the EPB machine, which was christened “Chris”. In addition, TunnelTec modified and augmented the existing tool concept to achieve a further enhancement of the total service-life of the tool equipment.

The line has an in-tunnel length of approx. 17.6 km. The system operator, Roma Metropolitane, awarded the project contract to the Metro C Joint Venture.

The Joint Venture selected two identical EPB machines for tunnel-heading from the “S.Giovanni” to “Venezia” station (Lot 3). These machines had already tunneled, together with two other EPB machines, Lots T6 – T4 from the “Torrenova” to the “S.Giovanni” station. A particular challenge involved in Lot 3 was the close proximity of the tunnel leading to the World Heritage Site of the Colosseum. The geology encountered during tunnel-heading work consisted mostly of gravel, sand and clay; in some cases it was necessary to tunnel through thick concrete walls at the start of tunnel-heading operations.

TunnelTec convinced the customer with a tunneling concept specially matched to this project. For this reason, the Metro C Joint Venture awarded TunnelTec the contract for initial equipping of both TBMs and for further replacement tools for the cutting wheels used.

The tunnel-heading work for the new wastewater tunnel, which runs from the Bergen Point treatment plant located in Suffolk County under the Great South Bay, was started in late 2019. The wastewater treated in the plant is conducted via the new tunnel bores to the receiving shaft, from which it is then discharged into the ocean via existing infrastructure.

The tunnel was headed using a slurry (mixed-shield) TBM with a boring diameter of 3.84 m and replaces the existing wastewater tunnel, which was threatened with collapse. The ground traversed consists predominantly of sand, silt and clay. The receiving shaft was reached on 25 January 2021 after completion of a tunneling length of 4.3 km.

Cutting tools specially developed by TunnelTec and incorporating especially high service-lives were used, in order to keep the number of tool changes during tunnel-heading work as low as possible.