Secure foundations for a new school in Givisiez: geotechnical engineering and construction supervision by GEOTEST
Givisiez
46° 81' 65, 7° 13' 13''E
2021 - 2026
The buildings are being constructed on the Les Taconnets site, which is owned by Transports publics fribourgeois (TPF). The site is currently being converted into a modern school and community centre. In addition to the school building with 36 classrooms, a triple-court gymnasium is being built directly adjacent to it. Operations are scheduled to start in 2028, with a planned expansion to around 800 pupils by 2030.
The plan drawn up by the architects at Atelier MARCH SA shows the location of the planned buildings directly between the road and the railway line.
Due to the limited space available, safety measures for the excavation pit (including nailed and slotted walls) are required on the road side, and a protective wall is required on the railway line side.
GEOTEST AG has been supporting the project since the initial planning stages, working closely with the planning team. The geotechnical, hydrogeological and environmental challenges are manifold: the heterogeneous and, in some cases, unstable construction ground requires deep foundations with piles. In addition, part of the terrain had to be raised, as the school building will be constructed without a basement or parking garage. The proximity to the railway line, heavy inflow of water from the slope, and tight construction schedule involving many contractors are additional factors influencing the construction work. GEOTEST is supporting the planning team in all geological and geotechnical aspects and is accompanying the execution of the work.
Along the soil nail wall facing the road, numerous built-in drainage openings ensure controlled diversion of water from the slope.
Drainage is necessary to remove water coming directly from precipitation and from the slope. The concept includes drainage ditches and pump sumps. Before the water can be discharged in an environmentally friendly manner, it is treated on site using a settling and neutralisation plant.
As part of the implementation of the planned geothermal probes (40 probes with a depth of 250 m), GEOTEST developed a concept for construction site wastewater management and accompanied its implementation. This service includes monitoring of the water treatment plant, hydrogeological support regarding high water inflows into the boreholes (>200 l/min per probe), and recording of the drill cuttings.
Settling and neutralisation plant for the geothermal boreholes.
Geothermal drilling conducted with two drilling rigs.
The services that have already been provided include construction ground investigations, clarification of soil contamination, and dimensioning of the excavation pit safety measures, pile foundations, and the protective wall on the railway line (SBB) side. GEOTEST also prepared the wastewater management plan and is monitoring the excavation pit walls using inclinometers. During the excavation, the company is accompanying the special civil engineering work and checking that it is being carried out properly on site.
The large drilling rig...
The concrete piles provide a secure foundation for the building and transfer the load to the molasse rock.
makes holes for the concrete piles.
This is how the Geneva-based firm MARCH SA visualises the finished school building.
The combination of complex construction ground, limited space, and the involvement of numerous specialist disciplines makes this a challenging project. With its expertise in geotechnics, environmental aspects, geothermal energy, and construction supervision, GEOTEST is ensuring that the new school site in Givisiez is built on a solidly planned and closely monitored foundation.
La succursale GEOTEST de Givisiez offre des conditions optimales pour cette mission... et pas seulement parce qu'elle se trouve presque à proximité immédiate du chantier.
