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Colline des Mathurins : Filling work with impressive volumes

The Colline des Mathurins project, in Bagneux (France), aims to transform a historically closed place into a sustainable district open to the city which must play its role of pivot between the city center and the southern districts. The real estate project consists by the construction of 300,000 m² of floor space, part of which (20,000 m²) for the rehabilitation of an existing building.

This project concerns a 15.6 ha right-of-way, a unique property formerly occupied by the Thomson-Thalès company for 50 years.


It is therefore in this context that Sefi-Intrafor (agent) intervenes for the restoration of the site. A project with extraordinary volumes since 170 linear km of drilling, 250,000 m3 of filler grout and 10,500 m3 of treatment injection are planned for the safety of this site undermined by the underground exploitation of the 1st, 2nd and 3rd masses of gypsum.


Even if the works are of a classic nature, and without great technical difficulty, the complexity of this work lies in the management of the phasing on the different lots (drilling, filling, keying, treatment) and in the co-activity with the other companies (demolition, earthworks). All this having imposed on the teams a very heavy and rigorous piloting on each batch.

Despite the impressive figures and the challenges, the project is ahead of schedule. In fact, 90% of phase 1 has already been completed and phase 2 will start 2 months ahead of schedule.


Efficiency made possible thanks to the human and material resources deployed (4 drilling workshops instead of the 2 planned and the new grout plant). Currently, the site mobilizes around thirty people with four drilling workshops on one workstation, a continuous production plant for filling and keying grout and a grouting plant.

Client : BNP Paribas Résidentiel, LBO France

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