FAIR – New International Accelerator Facility

The project involves building eight ring accel­er­a­tors with a circumference of approximately 1,100 m, two linear accel­er­a­tors and 3.5 km of beam tubes at depths down to 17 m, all covering an area of around 20 hectares, with an embankment of up to 15 m height acting as a radiation shield to cover the equipment.

We have been commissioned with all of the geotechnical consulting and planning services as well as on-site construction supervision for the project. Combined pile-raft foundations have been planned for all of the buildings except the accelerator ring. We used 3D finite-element calculations to investigate the load-bearing and deformation properties of the subsoil under future load conditions, with a load test on a bored pile at 60 m depth and test filling to improve planning and costs. This resulted in 1,350 piles at a depth of up to 62 m and 60,000 m in length completed within just 14 months – exceptional performance given the location of the construction site in a water reserve and the various requirements applicable to the site.

The next construction stage will see early preparation of deep excavation at down to around 19 m below ground, which will involve partly lowering the groundwater for protection. Secant pile walling with beam supports are planned to shore up the excavation area. The excavation pit will take around 57,000 m² of construction area in this section; around 880,000 m³ of soil will be excavated for intermediate storage in separate storage areas before being used for backfilling after shell construction.