1. CE 120 Introduction to Civil Engineering
Geotechnical Engineering
L. Sebastian Bryson
University of Kentucky

2. Introduction to Geotechnical Engineering
All Civil Engineering begins with Geotechnical Engineering
ground

3. Definitions
Soil mechanics is a discipline that applies the principles of engineering mechanics to soils to predict the mechanical behavior of soil.
Geotechnical Engineering is the branch of civil engineering that deals with soil, rock, and underground water, and their relation to the design construction and operation of engineering projects (Coduto 1998)

4. Typical Geotechnical Project
Geo-Laboratory ~ for testing
Design Office ~ for design & analysis
soil properties
design details
soil samples
construction site

5. Geotechnical Applications

6. Shallow Foundations
~ for transferring building loads to underlying ground
~ mostly for firm soils or light loads
bed rock
firm ground

7. Shallow Foundations

8. Foundation Systems
Designing of Shallow Foundations Systems – Bearing Capacity Failure
Transcona Grain Elevator
(from Budhu 2000)

9. Foundation Systems
Designing of Shallow Foundation Systems – Differential Settlement
Leaning Tower of Pisa

10. Deep Foundations
~ for transferring building loads to underlying ground P I L E
~ mostly for weak soils or heavy loads
bed rock
weak soil

11. Foundation Systems
Deep Foundation Systems: Driven Piles

12. Deep Foundations
Driven timber piles, Pacific Highway

13. Foundation Systems
Deep Foundation Systems: Drilled Shafts

14. Retaining Walls ~ Prevent soils from from spreading laterally
Road
Train
retaining wall
~ Prevent soils from from spreading laterally

15. Earth Pressure and Retaining Walls
Reinforced Earth Walls
(The Reinforced Wall Company 2003)

16. Retaining Structure Systems
Gavions
(Gaviones LEMAC (2003)

17. Retaining Structure Systems
Tie-backs
(Boulanger and Duncan 2003)

18. Retaining Structure Systems
Soil Nailing: steel rods placed into holes drilled into the walls and grouted

19. Retaining Structure Systems
Excavation Support Systems

20. Sheet Piles
~ sheets of interlocking steel or timber driven into the ground, forming a continuous sheet
ship
warehouse
sheet pile

21. Sheet Piles ~ resist lateral earth pressures ~ used in temporary works
~ used in excavations, waterfront structures

22. Sheet Pile Walls
(Boulanger and Duncan 2003)

23. Cofferdam
~ sheet pile walls enclosing an area, to prevent water seeping in
Cofferdams are often used in temporary works, to enclose the construction area within a continuous sheet pile wall around and protect it from water entering from outside.

24. Tunneling

25. Earth Dams
~ for impounding water
soil
reservoir
clay core
shell

26. Landslides

27. Earthworks ~ preparing the ground prior to construction
Roadwork, Pacific Highway

28. Geofabrics
~ used for reinforcement, separation, filtration and drainage in roads, retaining walls, embankments…
Geofabrics used on Pacific Highway

29. Geosynthetics Geosynthetic stabilized walls
(kshitija.wordpress.com 2007)
(Environmental Science & Engineering 2007)

30. Mechanically Stabilized Earth Walls
~ using geofabrics to strengthen the soil

31. Geoenvironmental Engineering
Characterization and remediation of Geo-environmental hazards
MSW Landfill
(from Willmer 2001)
(from Norwegian Geotechnical Institute 2001)

32. Geoenvironmental Engineering
Waste Disposal in Landfills

33. Instrumentation
~ to monitor the performances of earth and earth supported structures
~ to measure loads, pressures, deformations, strains
Finally, proof of the pudding is in the eating. Very often we monitor the performances of foundations, tie backs, embankments etc. for a long time after construction, to verify that it is performing to our expectations. Geotechnical engineering involves lots of uncertainty in the soil properties used in the designs and the theories. Instrumentation is a popular method to verify the theories, assumptions, construction methods etc.

34. Soil Testing
Vane Shear Test
Standard Penetration Test

35. Soil Testing
Cone Penetration Testing

36. Soil Testing
Triaxial Test on Soil Sample in Laboratory

37. Challenges
GeoHazards

38. Geotechnical Engineering Problems
How will the groundwater conditions impact the engineering project?
Teton Dam Failure (1975)

39. Geotechnical Engineering Problems
What will be the impact of excavations, grading, or filling?
Collapse of Nicoll Highway,Singapore, 2004

40. Geotechnical Engineering Problems
Are natural or proposed earth slope stable?
(from Norwegian Geotechnical
Institute, 2001)

41. Geotechnical Earthquake Engineering
Effects of earthquakes
1964 Niigata Earthquake Caracas Earthquake
(from Kramer –
1996)
(from Alshibli 2001)

42. Geotechnical Earthquake Engineering
Effects of earthquakes
1995 Kobe Earthquake Chi Chi Earthquake
(Boulanger and Duncan 2006)

43. Solutions
GeoSolutions

44. Ground Improvement
Impact Roller to Compact the Ground

45. Ground Improvement
Sheepsfoot Roller to Compact Clay Soils

46. Ground Improvement
Big weights dropped from 25 m, compacting the ground.
Craters formed in compaction

47. Soil Improvement
Stone Columns
(Boulanger and Duncan 2003)

48. Soil Improvement
Jet Grouting
(Boulanger and Duncan 2003)

49. Soil Improvement
Compaction Grouting
(Boulanger and Duncan 2003)

50. Soil Improvement
Chemical Injection
(Boulanger and Duncan 2003)

51. Thou shall not wait till the last minute to involve Geotechnical Engineers.

52. Geotechnical Engineers – Work Hard, Play Hard!