Rock Mechanics and Engineering Geoscience

EOSC316

Dr. Dan Faulkner

Rock Mechanics

• First 6 weeks: Rock Mechanics– 12 lectures– 6 practicals

• Second 6 weeks: Engineering Geoscience– 12 lectures– 6 practicals

• Assessment: 3 hour exam + 2 practicals

Course structure• Lectures 1-4

– Stress and strain• Lectures 5-8

– Rock fracture• Lectures 9-12

– Faults, friction and earthquakes

• Lectures 13-24– Engineering applications of Rock Mechanics– What can happen? How can we mitigate against it?

Recommended texts• 1st 6 weeks: Rock Mechanics

– Mechanics of Earthquakes and Faulting by Chris Scholz (2nd

Edition)• Stress and Strain by Win Means• Fundamentals of Rock Mechanics by Jaeger and Cook• Structural Geology textbooks for stress/strain

• 2nd 6 weeks: Rock Mechanics and Engineering Geology– Foundations of Engineering Geology by Tony Waltham– Practical Rock Engineering by Evert Hoek. Available free on the

web:• http://www.rocscience.com/hoek/PracticalRockEngineering.asp

Rock Mechanics

• Mechanics: study of motion and force• Emphasis on brittle rock mechanics (top 15

to 20 km of the Earth’s crust)– Fracture– Friction

Why is Rock Mechanics important?

• For understanding how the Earth works– Fault mechanics (earthquakes, etc)– Lithosphere strength– Propagation of seismic waves

• For design and analysis of man-made structures:– Dams– Tunnels– Waste repositories

Scale of observationsIn order to understand the processes that contribute to the failure process, we need to investigate what occurs on a small scale. Predictions of the macroscopic behaviour is based upon what happens physically at the microscopic scale.

Mechanistic rather than phenomenological approach

What can we do with rock mechanics?

• Engineering structures• Understand earth processes

Emosson Dam, Switzerland

Mersey tunnels: 1934 (Queensway) and 1971 (Kingsway)

Tunnels meet, 1928

Recent improvements to Kingsway

Golden Gate Bridge, San Francisco, 1937

Akashi Kaikyo Suspension Bridge, Kobe, Japan, 1998. 1991 m span

What happens when we don’t understand?

City Hall, San Francisco, 1906

Statue of Louis Agassiz,Stanford University campus,1906

Izmit earthquake,TurkeyM7.4, 17th August 1999

“We fundamentally don’t understand how earthquakes work. After all these years, we

don’t have a clue.”

Mark Zoback, Science, 1992

What happens when we get it wrong?

• Roads over landslips, Mam Tor• Vaiont dam disaster, Italy

The Vaiont dam disaster, Italian Dolomites, 1963

bThe Mam Tor head scar – looking west

The Mam TorLandslip