FCC   FCCIS      

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Abstract (D2.S1)

The layout and design of the underground structures will be summarised and a high-level explanation of the geological environment provided. An assessment of the soil/rock types that will need to be excavated will be given, together with the construction methods envisaged and an estimate of the volume of materials to be excavated. The areas requiring site investigations due to the uncertain geology of the subsurface will be identified with a view to reducing construction risks. The potential and motivations for staging certain civil engineering (CE) activities between FCC-ee and FCC-hh will be summarised and the resulting impact on the construction techniques and schedules will be discussed.

For the tunnel, the report will: ▪ describe the typical cross-section highlighting key features such as the ventilation spaces, drainage, tolerance envelope, etc.; ▪ provide typical construction methodologies for passing through the expected ground conditions; ▪ describe the geometrical layout of the underground RF infrastructure; ▪ describe the construction methodologies focussing on the vertical cores and the vertical access points, referencing HL-LHC as a recent experience of this type of construction technique; ▪ report the functional requirements for the injector tunnel and the envisaged CE solution; ▪ describe possible staged construction techniques for the beam dumps and comment on schedule impact if significant; ▪ describe options for staging CE activities between FCC-ee and FCC-hh, the resulting functional requirements and possible construction techniques, and comment on schedule impact if significant.

For the shafts, the report will: ▪ explain the one-shaft concept for the experiments; ▪ provide dimensions for typical shafts and an explanation of the ovoid shaft concept for the equipment shafts; ▪ provide typical construction methodologies for passing through moraine, molasse and limestone and for passing through water-bearing strata

For the caverns, the report will: ▪ describe a typical experiment cavern with dimensions, shape, etc.; ▪ describe a typical service cavern with dimensions, shape, etc.; ▪ mention the other caverns likely to be needed and their number; ▪ detail typical methodologies for the construction of caverns in molasse and limestone; ▪ outline the technical risks associated with the construction of large caverns; ▪ discuss staging options from FCC-ee to FCC-hh.