soil mechanics introduction to soil mechanics with basis of soil types and other descriptions

1. Subject Code: 150604
Geotechnical Engineering I
Civil Engineering Department
BITs edu campus, Vadodara
Third Year 1st Semester
GeotechnicalEngineeringI
1L. S. Thakur

2. 2
Historical Perspective
Soil Mech. & Geotech. Eng
The record of the first use of soil as a construction
material by man kind is lost in antiquity.
In true engineering sense, there is no ‘Geotechnical
Engineering’ prior to the 18th Century.
One of the most famous example of problems
related to soil bearing capacity and foundations in
the construction of structures prior to 18th century is
the Leaning Tower of Pisa in Italy. The construction
of the Tower began in 1173 A.D. and last over 200
years.

3. 3
Historical Perspective
Soil Mechanics and Geotechnical Eng
The Leaning Tower of Pisa, Italy.
Morning, 1 March 2004. SW
view
Height: 54 m;
Max tilt: 5 m out of plumb
Tilt direction: E, N, W, and S.
Weight: 15,700 tons;
Base: φ = 20 m;
Reason: a weak clay layer at 11
m depth
Solution: excavation of soil from
north side for about 70 tons.

4. 4
Historical Perspective
Soil Mechanics and Geotechnical Eng
Study of soil behavior in a more methodical manner in the
area of geotechnical engineering - early 18th century
The development of soil mechanics can be divided into four
phases, according to Skempton(1985):
1. Pre classical period (1700-1776): rough classification of
soils;
2. Classical soil mechanics –Phase I (1776-1856):started from
French scientist Coulomb’s presentation on determining the
sliding surface in soil behind a retaining wall; ended by the
publication of Rankine’s paper on earth lateral pressure.
Rankine’s theory is a simplification of Coulomb’s theory.

5. 5
Historical Perspective
Soil Mechanics and Geotechnical Eng
3. Classical soil mechanics –Phase II (1856-1910): started
from the publication of a paper on the permeability of sand
filters by French engineer Darcy in 1856.
4. Modern soil mechanics (1910-1927): marked by a series
of important studies and publications related to the
mechanic behavior of clays, most noticeable,
Atterberg(1911) on consistency of clayey soils.
Bell (1915) on lateral pressure and resistance of clays;
Terzaghi(1925) on theory of consolidation for clays.

6. 6
Historical Perspective
Soil Mechanics and Geotechnical Eng
Geotechnical Engineering after 1927
The development of Geotechnical Engineering as a
branch of Civil Engineering is absolutely impacted by
one single professional individual –Karl Terzaghi(1883-
1963).
His contribution has spread to almost every topic in soil
mechanics and geotechnical engineering covered by the
test book

7. 7
Historical Perspective
Soil Mechanics and Geotechnical Eng
Born: October 2, 1883 in Prague
Died: October 25, 1963 in Winchester,
Massachusetts
Married to Ruth D. Terzaghi, a geologist.
Won Norman Medal of ASCE four times
(1930, 1943, 1946, and 1955).
Was given 9 honorary doctorate degrees
from universities in eight different
countries.
Started modern soil mechanics with his
theories of consolidation, lateral earth
pressures, bearing capacity, and stability.

8. 8
Historical Perspective
Soil Mechanics and Geotechnical Eng
“Few people during Terzaghi’s lifetime would have disagreed
that he was not only the guiding spirit in soil mechanics, but
that he was the clearing house for research and application
throughout the world.” -Ralph B. Peck
Photo: Acceptance remarks
from life long educator
Ralph B. Peck at the OPAL
& 41st Annual OCEA
Awards gala held on April
28, 2001, Washington, DC.

9. 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

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

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

13. •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?
Design and Construction Issues

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

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

16. • 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?
Design and Construction Issues

17. http://www.geol.ucsb.edu/~arthur/Teton%20Dam/welcome_dam.html
TETON DAM
The Teton Dam, 44 miles northeast of Idaho Falls in
southeastern Idaho, failed abruptly on June 5, 1976. 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.

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

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

27. Loss of SupportBridge Collapse – Kobe EQ

29. Annual Damage in the U.S.

30. 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

31. Landfills

32. Source: Coduto, 1999
How to Prepare?

33. Historical Perspective
Geotechnical Hall of Fame:
http://www.ejge.com/People/HallFame.htm

34. Charles Augustin de Coulomb
• Grandfather of the Soil
Mechanics
• 1736-1806 (France)
• Friction and cohesion
concepts
• Lateral earth pressures on
retaining walls
• Structures, Hydraulics,
Mathematics, Electricity,
etc.

35. William John Maquorn Rankine
• 1820-1872 (Scotland)
• Thermodynamics and
soil mechanics
• Lateral earth pressure
theory
• Pioneering role as an
engineering educator

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

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

38. 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

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

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

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

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