Excavation carried out behind a Lutetian wall for the Variétés project in Toulouse
In the heart of Toulouse, the construction project for the ‘Les Variétés’ building, led by the client Caso Patrimoine with support from Green City Immobilier acting as project management assistant, was developed on an enclosed plot subject to significant constraints, directly adjacent to existing buildings and situated directly above the connecting tunnel between lines A and B of the Toulouse metro.
The architectural design was carried out by Taillandier Architectes Associés, in collaboration with structural engineering firm Terrell Group, and the works are being carried out by Socotrap and Botte Fondations.
In this particularly sensitive urban context, Terrasol was involved from early 2023 to April 2024, acting as the geotechnical engineering consultancy, first during the design phase (G2 PRO contract), then during the construction supervision phase (G4 contract).
The main challenge was to design a retaining structure compatible with sensitive neighbouring areas, ensure the stability of the historic façade during the temporary phase, and monitor the impact on existing infrastructure, particularly the underground metro tunnel.
The solution adopted was the installation of a Lutetian-type braced retaining wall, combined with a shotcrete wall. The project site consists successively of fill, alluvial deposits and then Toulouse molasse, in an environment where permissible movements were strictly limited.
Thanks to meticulous engineering and rigorous monitoring, stability and displacement criteria were met throughout the earthworks phase, ensuring the safety of neighbouring properties and existing infrastructure. Construction of the superstructure is now underway.
The project drew on all of Terrasol’s geotechnical expertise, with our engineers Laetitia Pavel and Florian Rocher playing a direct role in tackling the challenges of a complex underground construction site in the heart of the city.
A concrete example of bespoke geotechnical engineering serving the needs of a dense urban environment and sensitive underground projects.