fcc tunnel civil engineering and geology

FCC Tunnel Civil Engineering and Geology

John Osborne (CERN GS-SE) 4 April 2014

John Osborne (CERN) 2

• Goals of the meeting :

– Review status of studies– Ensure no duplication of tasks– Understand what geological data exists– Establish where to find additional data– BRGM contact– Understand the role of GIS– Agree reporting milestones and future review

dates

John Osborne (CERN) 3

Potential locations• Options for a ring tunnel have been proposed in

the past :

• Summer 2012 CERN GS-SE group studied the pre-feasibility of an 80km ring tunnel in the CERN area.

• Pre-feasibility study of an 80km tunnel project at CERN prepare for the European Strategy for Particle Physics 2012 : http://indico.cern.ch/event/175067/call-for-abstracts/165/file/1.pdf 4

1980’s :LEP 30km and 27km tunnel locations 2001 : VLHC 240km tunnel location1997 : VLHC 113km tunnel location

John Osborne (CERN GS-SE)

Potential locations : European Strategy for Particle Physics

• Several locations have been studied for the possibility to construct an 80-100km ring tunnel in the CERN area.

– Location constraints • CERN area• Connected to LHC/SPS at one point• Limit depth of access shafts

5John Osborne (CERN GS-SE)

Possible machine layouts

6P.Lebrun

7

Single tunnel, longitudinal ventilation

FCC I&O meeting, 140326 8

Single tunnel + refuge, longitudinal ventilation

FCC I&O meeting, 140326 9

Single tunnel, transverse ventilation

FCC I&O meeting, 140326 10

Single tunnelwith shielded technical & safety zones

11

Double tunnel

Feasibility /Risk Issues of the Options

Some examples of issues (needs to be studied in more detail)• Environment

– Risk of environmental impacts such as civil engineering, social acceptance, pollution of aquifers etc

– Risk of encountering hydrocarbons – Risk of EIA rejection

• Costs– Risk of cost increase due to all issues mentioned

12

Riskwater

ingressheaving ground

weak marls

hydrocarbons

support &

lining

ground response & convergenc

e

hydrostatic pressure

& drainage

Pollution of

aquifers

effect of

shafts on

nature

effects of

shafts on

urban areas

Total

Option 1

5 3 0 0 5 4 5 5 4 2 33

Option 2

2 0 3 3 3 3 2 2 3 2 23

Option 3

…….

1 0 2 2 2 2 1 1 2 5 18

High

LowFeasibility

John Osborne (CERN GS-SE)

• Develop a geological tool to allow comparison of the various tunnel options

• Circumferences, shapes, inclination (max 2%, out of plane ?) etc. to be easily compared

• non-planar tunnel ?• Optimise shaft positions to

minimise depth (+/- 2km ?)• Bypass tunnels instead of

shafts ?

John Osborne (CERN) 13

Next Steps

John Osborne (CERN) 14