directional core drilling in tunnel construction
DESCRIPTION
Directional core drilling in tunnel construction. Directional core drilling. Devico AS Borehole survey systems Directional core drilling DeviDrill directional core barrel First version in 1988 Present version in 2001 Projects Geotechnical exploration Mineral exploration. - PowerPoint PPT PresentationTRANSCRIPT
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Directional core drilling in tunnel
construction
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Directional core drilling
• Devico AS• Borehole survey systems• Directional core drilling
• DeviDrill directional core barrel• First version in 1988• Present version in 2001
• Projects• Geotechnical exploration• Mineral exploration
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Geotechnical exploration
• Change direction of boreholes• Steer towards targets or keep hole within limits• Retrive core from the most relevant areas
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Coring along planned tunnel alignment
• Continuous rock core• Fault zones• Fractures• Geological anomalies• Rock mechanical properties
• Hole for various analysis• Geophysical• Water in-/outflow• Hydraulic fracturing
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Directional coring in Hong Kong
• 4 projects completed last five years• Traffic tunnels (2)• Drainage tunnels (4)• Sewage tunnels (6)
• Guidance note from the HK Government• “4.1 Directional drilling techniques are now available to drill from
ground level to great depth and then along a horizontal alignment. This method does not require provision of working space at the tunnel level and can be very useful in GI for deep tunnels.”
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Eagle’s Nest
• 2 boreholes• 580 and 1150 meters• 8 m radius tolerance• Borehole between twin
tunnels• Fault zones
Pressure grouting schedules
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Harbor Treatment Scheme, Stage II
• 6 boreholes• 600 to 1250 meters• 10 x 10m tolerance• Start inclination from -33° to -45°
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Conclusion
• Accurate impression of the rock formations along the tunnel alignment
• Security during construction• Stabilization measures• Predict leakage and ground setting• Material estimations• Time & cost estimations
• Achieves reliable results, proven in mining and geotechnical exploration projects worldwide
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Thank you for your attention!
www.devico.com