Geotechnical Engineering

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1 Geotechnical Engineering CE 3348 Lecture 1: Introduction Instructor: Reza Ashtiani, Ph.D. Spring 2018 UGLC 342 Lecture Sessions : MW 12:30-1:20 pm Laboratory Sessions: MWF 1:30-4:30 pm

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9 Income by Experience Civil and Mechanical Engineering (2012) 9

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Course Structure Textbook: An Introduction to Geotechnical Engineering, 2nd Edition by Holtz, Kovacs and Sheahan, Publisher: Prentice Hall, 2011. Class Website: Site Password: www.rezasalehi.

11 Course Structure Textbook: An Introduction to Geotechnical Engineering, 2nd Edition by Holtz, Kovacs and Sheahan, Publisher: Prentice Hall, Class Website: Site Password: students Grading: 1. Final Comprehensive Exam (300 points) 2. Two Mid-Term Exams (300 points) 3. Laboratory Reports (200 points) 4. Homework Assignments (200 Points) 5. Critical Assessment (attendance and involvement in class discussions) (50 points) Total: 1050 Points 11

Mechanical Analysis of Soils CE 3348-Geotechnical Engineering Physical Properties of Soils Course Outline Weight-Volume Relations Soil Texture Soil

Effective Stress Pore Water Pressure Geostatic Stresses Effective Stress Calculations Flow of Water in Soils 1D-Flow Theory Soil Permeability Darcy

Analysis Boussinesq Theory Westergaard Theory Mohr-Coulomb Theory Mohr Circle Direct Shear Test Triaxial Tests Immediate Settlement Primary

12 Mechanical Analysis of Soils CE 3348-Geotechnical Engineering Physical Properties of Soils Course Outline Weight-Volume Relations Soil Texture Soil Classification Phase Diagrams Atterberg Limits Aggregate Geometry USCS Method AASHTO Method Soil Plasticity Shrink-Swell Potential Soil Compaction Effective Stress Pore Water Pressure Geostatic Stresses Effective Stress Calculations Flow of Water in Soils 1D-Flow Theory Soil Permeability Darcy s Law Constant Head Permeability Test Falling Head Permeability test 2D-Flow Theory Flow Nets External Stresses Shear Strength of Soils Settlement Analysis Boussinesq Theory Westergaard Theory Mohr-Coulomb Theory Mohr Circle Direct Shear Test Triaxial Tests Immediate Settlement Primary Consolidation Secondary Compression Time Rate of Settlement Newmark Method Consolidated Drained (CD) Consolidated Undrained (CU) Unconsolidated Undrained (UU) 12

13 CE3348 Score Card Previous Semester (Spring 2017) Item Description Quantity Lecture Topics 9 Lecture Segments 16 PowerPoint Slides 651 Solved Examples in the Class 34 Laboratory Tests 7 Laboratory Reports 7 Homework Assignments 6 Homework Problems 45 Exams 3

14 Distinction between Geotechnical Engineering and Geology Geotechnical engineering is a branch of civil engineering, whereas engineering geology is a branch of geology. These two disciplines are closely related, and the discipline combining the two is sometimes called geotechnics. Note: This illustration is not a complete listing of the branches of either discipline. 14

15 Course Objective Provide students with physical, mechanical, and mathematical tools and concepts for the understanding of engineering behavior of soils and introduction to engineering design of geotechnical systems. 15

16 Significance of the CE3348 Course All the civil engineering structures, whether built on earth or any other continuum, is greatly influenced by the foundation. The performance and safety of civil engineering structures are primarily dependent on proper characterization of soil-structure interaction. 16

17 Definitions of Soils According to a geologist, Soil is the material in the relative thin surface zone within which roots occur, and all the rest of the crust is grouped under the term ROCK irrespective of its hardness. According to a civil engineer, Soil is the unaggregated or un-cemented deposits of mineral and/or organic particles or fragments covering large portion of the earth's crust. 17

18 Definitions, cont. Soil mechanics is a discipline that applies the principles of engineering mechanics to soils to predict the mechanical behavior of granular materials. 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. 18

19 Components of Soil Mechanics Geological Characteristics of Soil Physical Soil Parameters Seepage though Soils Stress and Strain in Soils Effective Stresses Deformation in Soils Shear Stress in Soils 19

20 Examples of Geostructures Buildings the Sears Tower in Chicago is one of the tallest buildings in the world (1450 ft.,110 story). It needs massive foundations to transmit the structural loads into the ground. The design of these foundations depends on the nature of the underlying soils. Geotechnical engineers are responsible for assessing these soil conditions and developing suitable foundation designs. 20

21 Examples of Geostructures Bridges the foundation for the south pier of the Golden Gate Bridge in San Francisco had to be built in the open sea. It extends down to bedrock, some 30 m (100 ft) below the water level and 12 m (40 ft) below the channel bottom. This was especially difficult to build because of the tremendous tidal currents at this site. 21

It is made of 61,000,000 m 3 (80,000,000 yd 3 ) of compacted soil.

22 Examples of Geostructures Dams Oroville Dam in California is one of the largest earth dams in the world. It is made of 61,000,000 m 3 (80,000,000 yd 3 ) of compacted soil. The design and construction of such dams require extensive geotechnical engineering expertise. 22

This prefabricated tunnel section was floated to the job site, and then

23 Examples of Geostructures Tunnels the Ted Williams Tunnel is part of the Central Artery Project in Boston. This prefabricated tunnel section was floated to the job site, and then sunk into a prepared trench in the bottom of the bay. Its integrity depends on proper support from the underlying soils. 23

24 Failure of Geostructures The leaning tower of Pisa. (Adapted from Terzaghi 1934a.) 24

25 Failure of Geostructures Slope failure 25

26 Failure of Geostructures This house was built near the top of a slope and had a beautiful view of the Pacific Ocean. Unfortunately, a landslide occurred during a wet winter, undermining the house and causing part of its floor to fall away. 26

27 Failure of Geostructures 27

28 Failure of Geostructures Teton Dam in Idaho failed in 1976, only a few months after the embankment had been completed and the reservoir began to be filled. This failure killed 14 people and caused about $400 million of property damage. (Picture Courtesy of the Bureau of Reclamation) 28

29 Failure of Geostructures The 1964 Niigata Earthquake in Japan caused extensive liquefaction in this port city. These apartment buildings rotated when the underlying soils liquefied. (Courtesy of Earthquake Engineering Research Center Library, Berkeley, California.) 29

30 Failure of Geostructures The approach fill to this highway bridge has settled because the underlying soils are soft clays and silts. However, the bridge has not settled because it is supported on piles. Although this failure is not as dramatic as the others, it is a source of additional maintenance costs, and can be a safety hazard to motorists and pedestrians. 30

31 Geotechnical Design Design is the process whereby a problem is solved for a certain conditions and constrains, and meeting specified performance criteria. This definition applies to any civil and geological engineering system. 31

32 Basic Geotechnical Engineering Design and Analysis Projects Bearing capacity of soils: design of shallow and deep foundations Lateral Earth Pressure: design of retaining structures Slope stability problems Design of earth dams Ground improvement Pavement and runway foundations Geosynthetic design Geo-environmental engineering 32

33 Foundation Systems Designing of Shallow Foundation Systems Differential settlements Canada's Leaning Tower or the "Kissing Silos (from Sharma 2003) 33

34 Foundation Systems Deep Foundation Systems: Driven Piles 34

35 Foundation Systems Deep Foundation Systems: Drilled Shafts 35

36 Earth Pressure and Retaining Walls 36

37 Earth Pressure and Retaining Walls (The Reinforced Wall Company 2003) 37

38 Retaining Structures and Sheet Piles (Boulanger and Duncan 2003) 38

39 Retaining Structures (Gaviones LEMAC (2003) 39

40 Retaining Structure Systems (Boulanger and Duncan 2003) 40

41 Retaining Structure Systems Excavation Support Systems (Boulanger and Duncan 2003) 41

42 Geosynthetics Geosynthetic stabilized walls (kshitija.wordpress.com 2007) (Environmental Science & Engineering 2007) 42

43 Ground Improvement Stone Columns (Boulanger and Duncan 2003) 43

44 Ground Improvement Jet Grouting (Boulanger and Duncan 2003) 44

45 Ground Improvement Injection Grouting (Boulanger and Duncan 2003) 45

46 Ground Improvement Chemical Injection (Boulanger and Duncan 2003) 46

47 Geo-Environmental Engineering Municipal Solid Waste (MSW) Landfill (from Willmer 2001) (from Norwegian Geotechnical Institute 2001) 47

48 A nation that destroys its soils, destroys itself. President Franklin D. Roosevelt, Feb. 26, National Archives: 114 SC

Geotechnical Engineering

Geotechnical Engineering CE 4348 Lecture 1: Introduction Instructor: Reza Ashtiani, Ph.D. Fall 2015 Physical Science Bldg., Room 314 Lecture Sessions : MW 12:30-1:20 pm Laboratory Sessions: MW 1:30-4:30