Arrival of the tunnel boring machine Malala – Grand Paris Express

TBM Malala Arrival

Presentation of the T2C L15-Sud section T2C project on the Grand Paris Express

Contractor: ALLIANCE Group (Grouping Demathieu Bard NGE, and Pizzarotti).

Engineering: SYSTRA

Asset Owner: Société Grand Paris (SGP)

Location: Between Noisy Champs and Bry-Villiers sur Marne and Champigny sur Marne

Length: Total tunnel length is seven kms with two TBM’s. Two terminal stations serve as a starting point for each tunnel boring machine. One disassembly station and seven intermediate structures comprise the tunnel-boring project.

The 7km-long project is subdivided into three sections.

Grand Paris Express T2C L15-Sud Cementys
Monitoring objectives

As part of the “Grand Paris Express line 15, T2C section”, the monitoring mission of Cementys aims to:

  • Monitor and analyze the behavior of the soil around construction;
  • Monitor and analyze the behavior of structures under construction in the short term and ensure site safety;
  • Oversee the sustainability of the tunnel and its structures in the long term, during post-construction operations;
  • Monitor the impact of the execution of the tunneling and the building of the structures, by monitoring and analyzing the behavior of neighboring buildings, existing structures, civil infrastructure, sensitive utility networks, etc.
TBM Monitoring

Cementys has placed approximately 1,500 prisms on the buildings located in the GIZ (Geotechnical Influence Zone).

For the measurements on the prisms of the buildings, a total of 15 automatic stations were installed for monitoring the TBM 2 from the start of digging until its arrival at the disassembly station.

Cementys installed 250 leveling rivets between the two terminal stations for surface monitoring of deflections. The measurements are made manually using a level of precision and surveying by the field team.

Cementys team drilled 37 boreholes for installation of measurement sensors, including 18 holes inclinometers, 9 for extensometers, and 8 for piezometers.

15 rings were instrumented with extensometers and pore pressure cells, embedded in concrete.

TBM Malala arrival

TBM2, Malala, which started in September 2018 arrived at the level of “the Cave” at the end of February 2020. It underwent a series of maintenance to resume its activity (postponed following the Covid-19 crisis).

The TBM Malala now is scheduled to restart on 11 May 2020 to continue digging to BVC station. Here are some pictures of his arrival:

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