1. The Leaning Tower of Pisa
GEOTECHNICAL ENGINEERING
The Leaning Tower of Pisa

2. Why Geotechnical Engineering?
“Virtually every structure is supported by soil or rock. Those that aren’t - either fly, float, or fall over.”
-Richard Handy, 1995

4. Case Study I: Building Foundation
Weight of building (DL + LL) = 37,000 tons
Weight of excavated soil = 29,000 tons
15-ft soft fill and organic silt
20 ft of sand and gravel
Soft Clay Soil
75 ft
Firm Soil or Bedrock
Estimated settlement due to the net load of clay (37,000 – 29,000 = 8,000 tons) = 2-3 in.
Initial estimated settlement = 1 ft
Source: Lambe & Whitman, 1969

5. Building 10 on M.I.T.’s Campus – Photo by Professor Zoghi, Sept. 1984

6. Design and Construction Issues
How deep?
Size of the footing (mat foundation)?
Groundwater table?
Dewatering?
Braced excavation?
Damage to adjacent buildings?
Quantity and rate of the estimated settlement?
Stress distribution?
Design bearing capacity?

7. Alternative Foundations
Pile type?
How deep?
Spacing?
Maximum allowable load?
Pile efficiency?
Driving/drilling?
Optimum sequence of driving piles?
How much variation from vertical?
Adjacent buildings?

8. Case Study II: Earth Dam
Source: Lambe & Whitman, 1969
Zoned Earth Dam

9. Design and Construction Issues
Dimensions? (Most economical design)
Thickness of the rock facing and gravel to keep swelling of clay core to a tolerable amount?
The moisture content and compaction technique (lifts, equipment, etc) to place gravel and clay?
Permeability and seepage characteristics of the dam?
Consolidation and settlement characteristics of underlying soil?
Shearing strength parameters?
Potential leakage under and through the dam?
Factor of safety of upstream and downstream slopes?
Rapid draw down effect?
Seismic activity?

10. TETON DAM
The Teton Dam, 44 miles northeast of Idaho Falls in southeastern Idaho, failed abruptly on June 5, It released nearly 300,000 acre feet of water, then flooded farmland and towns downstream with the eventual loss of 14 lives, directly or indirectly, and with a cost estimated to be nearly $1 billion.

17. Teton Dam Failure - Flood waters advancing through Rexburg, Idaho.

19. Landslides
In excess of $1 billion in damages and 25 to 50 deaths each year in U.S.

20. Loss of SupportBridge Collapse – Kobe EQ

22. Annual Damage in the U.S.

23. Geo-Environmental Municipal Solid Waste
Approx. 3.6 lbs trash per person per day
Total trash = 216 million tons
Make up:
40% Cardboard
18% yard waste
9% metals
8% plastic
others

24. Landfills

25. How to Prepare?
Source: Coduto, 1999

26. Historical Perspective
Geotechnical Hall of Fame:

27. Charles Augustin de Coulomb
Grandfather of the Soil Mechanics
(France)
Friction and cohesion concepts
Lateral earth pressures on retaining walls
Structures, Hydraulics, Mathematics, Electricity, etc.

28. William John Maquorn Rankine
(Scotland)
Thermodynamics and soil mechanics
Lateral earth pressure theory
Pioneering role as an engineering educator

29. Karl von Terzaghi The Father of Soil Mechanics
1883 (Prague) – 1963 (Massachusetts)
Coined the phrase…
First publication in 1925
Great many contributions

30. Arthur Casagrande 1902 – 1981 Worked closely with Terzaghi
Started soil mechanics at Harvard
Received numerous awards
Fundamental soil mechanics problems…

31. Ralph Brazelton Peck 1912 – Winnipeg, Canada
Co-authored a textbook with Terzaghi
Initially a bridge designer…
Several decades as a pioneering foundation engineer and educator
Numerous awards

32. Alec Westley Skempton 1914-2001 (UK)
Established soil mechanics at Imperial College
Soil mechanics problems, rock mechanics, geology, and history of civil engineering

33. Nilmar Janbu 1920 - NTNU – Norway
Ph.D. student of Casagrande at Harvard
Slope stability problems – Janbu Method
Landslides in quick- clay

34. Laurits Bjerrum 1918-1973 The First Director of NGI (1951-1973)
Quick clay
Progressive failure of slopes
A “Giant”

35. Harry Bolten Seed
1922 – 1989
Father of Geotechnical Earthquake Engineering
UC Berkley
Pioneering work in Geohazards