Fundamentals of engineering geology

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Fundamentals concepts of Engineering Geology. A Glimpse of engineering geology and rock mechanics

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  • Pile foundations are the part of a structure used to carry and transfer the load of the structure to the bearing ground located at some depth below ground surface. The main components of the foundation are the pil
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Fundamentals of engineering geology

  1. 1. National University of Malaysia Engineering Geology (A Glimpse of Engineering Geology and Rock Mechanics) Wan Zuhairi Wan Yaacob (Assoc. Prof, PhD) Faculty of Science and Technology National University of Malaysia 43600 Bangi, Selangor, MALAYSIA. 28-Jan-14 1
  2. 2. Contents National University of Malaysia • Introduction • Fundamentals of Engineering Geology • Case studies 28-Jan-14 2
  3. 3. National University of Malaysia Introduction ALL Civil Engineering works are carried out on or in the ground Hoover Dam, Colorado Tunnel in Wales, UK Underground mining “An engineer is a person who can do for one dollar what any fool can do for two” Matthewson, 1981. 28-Jan-14 3
  4. 4. Geology & Civil Engineering National University of Malaysia GEOTECHNOLOGY Engineering in earth materials Engineering Geology (Geological Engineering) Civil Engineering Mining Engineering A. Roberts (1977). Geotechnology: An Introduction text for students and engineers. B. Pergamon Press. 28-Jan-14 4
  5. 5. ENGINEERING GEOLOGY (Geological Engineering) National University of Malaysia Engineering geologist as a “two-faced” professional looking back at geologic processes and forward to engineering products 28-Jan-14 5
  6. 6. Fundamentals of Engineering Geology • Lithology / Rock Type • Rock Structure • Rock Weathering National University of Malaysia Rock Type Rock weathering fresh weathered Rock structures 28-Jan-14 6
  7. 7. National University of Malaysia Rock Type (Lithology) 28-Jan-14 7
  8. 8. 3 Major Rock Types 28-Jan-14 National University of Malaysia 8
  9. 9. Definitions of rocks: National University of Malaysia • Architect – Rock is a type of building material, dimension stone • Engineer – Rock as a hard or brittle material that requires BLASTING to excavate. – A permanent, durable material for erosion control or engineering uses. • Geologist – Rock is an earth material produced by the rock forming processes; OR – Rocks are natural earth materials composed of aggregates of one or more minerals 28-Jan-14 9
  10. 10. Two main engineering properties of rock : National University of Malaysia • (1) Rock Substance – The properties of the intact, unfractured rock specimen. • (2) Rock mass – The entire rock body – Incl. fractures and discontinuities 28-Jan-14 10
  11. 11. National University of Malaysia Rock Substance Rock mass 28-Jan-14 11
  12. 12. National University of Malaysia Rock material View under the microscope Interlocking of minerals Cemented grains/minerals Core samples 28-Jan-14 12
  13. 13. Rock Mass National University of Malaysia Rock materials + discontinuities (i.e. joints, fractures, faults, folds, planes) 28-Jan-14 13
  14. 14. Strong vs weak rocks 28-Jan-14 National University of Malaysia 14
  15. 15. National University of Malaysia Rock Structures (or discontinuities) 28-Jan-14 15
  16. 16. Earth forces & the deformation of rocks National University of Malaysia • Stresses (TEGASAN); (P = F/A) – Compression • Acts to compress objects – Tensional • Acts to stretch objects – Shear • Complex kind of stress • Opposite sites 28-Jan-14 16
  17. 17. Elastic-plastic deformation (In Laboratory) National University of Malaysia Material A Plastic 28-Jan-14 fracture 17
  18. 18. In the field… SESAR / FAULT 28-Jan-14 National University of Malaysia LIPATAN / FOLD 18
  19. 19. TYPE ??? WHY ??? 28-Jan-14 National University of Malaysia 19
  20. 20. National University of Malaysia 28-Jan-14 20
  21. 21. National University of Malaysia How to describe discontinuities: • • • • • • • • • • 1. Orientation 2. Spacing 3. Persistence 4. Roughness 5. Wall strength 6. Aperture 7. Filling 8. Seepage (water) 9. Number of sets 10. Block size 1 2 3 6 7 4 5
  22. 22. National University of Malaysia Discontinuity and dams • Orientation (1) Axis of dam (favorable) 28-Jan-14 (unfavorable) 23
  23. 23. Discontinuity and slope National University of Malaysia • Orientation (2) Inclination away from the road (stable) Inclination towards the road (less stable) Unstable block 28-Jan-14 24
  24. 24. National University of Malaysia Weathering 28-Jan-14 25
  25. 25. National University of Malaysia Weathered Granit (Grade III-IV) Fresh Granit (Grade I) 28-Jan-14 26
  26. 26. Rock Soil National University of Malaysia 28-Jan-14 27
  27. 27. National University of Malaysia 28-Jan-14 28
  28. 28. National University of Malaysia Engineering Rock Classification 28-Jan-14 29
  29. 29. Rock mass classification National University of Malaysia • Rock mass classification is a means of evaluating the quality (strong/weak) and expected behavior of rock masses based on the most important parameters that influence the rock mass quality. 28-Jan-14 30
  30. 30. 1. Rock Quality Designation (RQD) system (Deere et al, 1967). National University of Malaysia • The cumulative length of intact core pieces longer than 10cm in a run divided by the total length of the core run. Sum of lengths of core sticks > 10 cm long x 100 Total length of core run 28-Jan-14 31
  31. 31. Core recovery National University of Malaysia • The ratio of the length of core recovered to the length drilled • Ranges from 0% (no core recovery) to 100% (total recovery) % Core recovery = total length of core samples (1,2,3) x 100 core run length 28-Jan-14 32
  32. 32. National University of Malaysia Core recovery 10cm = (2.0)/(2.0) x 100% = 100% 2.0m RQD = (2.0)/(2.0) x 100% = 100% (Excellent!) 28-Jan-14 33
  33. 33. National University of Malaysia Rock Quality Designation RQD <25% Very Poor 25-49% Poor 50-74% Fair 75-89% Good 90-100% 28-Jan-14 Rock Quality Classification Excellent 34
  34. 34. 2. ROCK MASS RATING (RMR) National University of Malaysia • Proposed by Bieniawski (1981) • The South African Geomechanics Classification (SAGC) RMR = JA1 + JA2 + JA3 + JA4 + JA5 + JB • SIX parameters are required: 1. Uniaxial compressive strength (JA1) 2. RQD (JA2) 3. Discontinuity spacing (JA3) 4. Conditions of the discontinuities (JA4) 5. Groundwater (flow and general conditions) (JA5) 6. Rating adjustment for discontinuity orientations (JB) • Based on ratings (total of 6 ratings) • Total ratings (0-100) will give rock mass classes (I to V). 28-Jan-14 35
  35. 35. RMR 28-Jan-14 National University of Malaysia 36
  36. 36. National University of Malaysia Case study: St. Francis Dam Failure 28-Jan-14 37
  37. 37. National University of Malaysia dam CASE STUDY: St. Francis Dam, US •12 March 1928 •500 dead •Geological factors •The science of Eng. Geol dwzwy2004_2005
  38. 38. National University of Malaysia dam Dipping 50o San Francisquito fault: a branch of San Andreas fault •12 March 1928 •500 dead •Geological factors •The science of Eng. Geol dwzwy2004_2005 An engineering geologist knows a dam site better !!
  39. 39. National University of Malaysia • “this substrate was totally inappropriate for a dam footing, and failure of fractured and weathered conglomerate was the major cause of the dam failure”. • “Don’t blame anyone else, you just fasten it on me. If there was an error in human judgment, I was the human.” (William Mulholland, dam’s chief engineer & architect). dwzwy2004_2005
  40. 40. National University of Malaysia Thank you 28-Jan-14 41

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