Yung Loo

25.06.2014

FCC: GIS & Tunnelling Update

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FCC: GIS & Tunnelling Update

1. GIS Progress

2. Alignment: Horizontal / Laser Straight

3. Data Interpolation

4. Preliminary Findings• LHC Crossing under ATLAS Point 1• Bored vs IMT

• Total Shaft Depths• Risk Matrix

5. Next Steps

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GIS Tool Development – Current Status

Web-based GIS Decision Aid Tool

Dynamic Chart:• Profile surface elevation

and geology• Profile of tunnel• Shaft Locations • Warnings when tunnel

above ground level

Dynamic Tables:

• Depth to tunnel • Shaft Length through

geology layers• % age of tunnel

intersecting geology• ±3km horizontal

variance in results for shaft depth

User Inputs• Alignments of 6 FCC Options• Interactive alignment location on map• Alter Shaft locations (10%) - slidebar• Select Tunnel Depth - slidebar• Select Tunnel Gradient – slidebar• Select point of inflection of tunnel gradient

Outputs

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GIS Tool Development – Current Status

Web-based GIS Decision Aid Tool

Dynamic Chart:• Profile surface elevation

and geology• Profile of tunnel• Shaft Locations • Warnings when tunnel

above ground level

Dynamic Tables:

• Depth to tunnel • Shaft Length through

geology layers• % age of tunnel

intersecting geology• ±3km horizontal

variance in results for shaft depth

User Inputs• Alignments of 6 FCC Options• Interactive alignment location on map• Alter Shaft locations (10%) - slidebar• Select Tunnel Depth - slidebar• Select Tunnel Gradient – slidebar• Select point of inflection of tunnel gradient

Outputs

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GIS Tool Development – Current Status

1 2 3 4 5 6 7 8 9 10

To Develop:

• Cretaceous boundary:• Basement• Massifs Calcaire

• Lake Superficials/Moraine

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Geographic Reference System

• Alignment Geographic Reference System:- Laser straight / Earth curvature- Geoid- Ellipsoid- Inherent distortion

ILC for CERN Site (Horizontal)

This was ok for ILC

Geographic Reference System

• FCC Tunnel alignment is following Earth curvature and appears horizontal as flattened

when projected with LV95

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Geographic Reference System

WGS 84 Swiss Lv95

• A geographic coordinate system (WGS84), uses a 3d spherical surface to define locations on the earth.

• A projected coordinate system (Swiss Lv95) is defined on a flat, 2d surface.

• All data uses Swiss Lv95, which effectively ‘flattens’ the data and removes the curvature of the earth.

• Therefore this flattening removes any curvature in the alignment when viewed in profile.

Datasets• Terrain:

Shuttle Radar Topography Mission (SRTM)

• Geology:Le système d'information du territoire à Genève (SITG)

• Coordinate System:SwissLV95

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Geographic Reference System

• Swiss LV95: Geographic coordinate system- Uses Bessel 1841 ellipsoid- x,y,z derived directly from a fundamental point at Zimmerwald

Federal Office of Topography, swisstopo

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Geographic Reference System• Scale Distortion: 75-100ppm ~ 2.4-3.1m over 31.8km (~relative 0.7m)

• Meridian Convergence: angular difference from north (-0.9 to -1.0, ~relative 0.1º)

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Point Interpolation

• PostGIS function which interpolates a point on a line. Location of point is a fraction of total length of the line.

• 1% intervals used. • For 100km alignment, a point every 100m.

83km, a point every 83m.

• All geology information has been converted to raster format using the ‘Topo to Raster’ tool in ArcGIS

• Uses an iterative interpolation technique, based on IDW and kriging.

• Optimised to have computational efficiency of local interpolation methods without losing surface continuity of global interpolation methods.

• Allows for the created DEM to follow abrupt changes in elevation.

P3P1 P7

(450m)(359m) (350m)

FCC (horizontal)

FCC (at grade)

?m

Superficials

MoraineMolasse

Tunnellingunder lake

(330m)(310m)

(230m)

Vertical depth below Point 1

30m

50m130m

Effect of tunnel position on Point 1 connection

Alignment & Tunnelling Type – Preliminary Results

To be updated with Cretaceous geology

Horizontal Alignment: Above GL

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Lake Crossing: Tunnelling Considerations

IMT Bored Bored Remarks

Ground conditions Superficials Moraine MolasseGeotechnical Risks, with which can

be designed for.

Excavation Technology + + ++

All proven technology at the anticipated depths, lengths &

diameter. More extensive ground treatment in non-molasse options

Logistics: Segmental vs prefab and casting basin

- + +Navigation issues, inland segment

yards, near shore casting yards, floating docks

Long term durability: Stability, joints, maintenance & operation

+ - - Increased joint connections in TBM

Environmental: Spoil disposal, dredging, ship impacts

- + +IMT dredging can be used directly as

construction material

Energy: Power and fuel consumption

+ - -IMT less energy requirements, more

fuel requirements

Cost and programme ? ? ?To determ

ine furth

er in st

age 3

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Next Steps- GADZ Cretaceous data inclusion- GIS programming completion and integration- Screening results- Stage 2: Requirements, constraints & alignment optioneering