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 pm

Top 10 Majors with the Highest

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Top 10 Majors with the Highest

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Top 10 Majors with the Highest

Earnings at the 25th Percentile

Income by Experience

Civil and Mechanical Engineering (2012)

Income by Degree Earned and Length of Experience

Civil and Mechanical Engineering (2012)

Course Structure

Textbook: An Introduction to Geotechnical Engineering, 2nd Edition by Holtz, Kovacs and Sheahan, Publisher: Prentice Hall, 2011. Class Website: www.rezasalehi.com/CE-4348 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

CE

43

48

-Geo

tech

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Eng

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Ph

ysic

al P

rop

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es o

f So

ils

Weight-Volume Relations

Phase Diagrams

Soil Texture Atterberg Limits

Soil Plasticity

Shrink-Swell Potential Aggregate Geometry

Soil Classification USCS Method

AASHTO Method

Soil Compaction

Mec

ha

nic

al A

na

lysi

s o

f So

ils

Effective Stress Pore Water Pressure

Geostatic Stresses Effective Stress

Calculations

Flow of Water in Soils

1D-Flow Theory Darcy’s Law

Soil Permeability

Constant Head Permeability Test

Falling Head Permeability test

2D-Flow Theory Flow Nets

External Stresses Boussinesq Theory Newmark Method

Westergaard Theory

Shear Strength of Soils

Mohr-Coulomb Theory

Direct Shear Test

Triaxial Tests

Consolidated Drained (CD)

Consolidated Undrained (CU)

Unconsolidated Undrained (UU)

Mohr Circle

Settlement Analysis

Immediate Settlement

Primary Consolidation

Secondary Compression

Time Rate of Settlement

Item Description Quantity

Lecture Topics 9

Lecture Segments 16

PowerPoint Slides 651

Solved Examples in the Class 34

Laboratory Tests 7

Laboratory Reports 5

Homework Assignments 6

Homework Problems 45

Exams 3

CE4348 Score Card Previous Semester

• 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.

Course Objective

Significance

• All the civil engineering structures,

weather 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.

• 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 un-

aggregated or un-cemented deposits of

mineral and/or organic particles or fragments

covering large portion of the earth's crust.

Definitions of Soils

• 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.

Definitions

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.

• 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

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.

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.

Dams—Oroville Dam in California is one of the largest earth dams in the world. It

is made of 61,000,000 m3 (80,000,000 yd3) of compacted soil. The design and

construction of such dams require extensive geotechnical engineering experties.

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.

The leaning tower of Pisa. (Adapted from

Terzaghi 1934a.)

Slope failure

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.

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)

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.)

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.

Basic Geotechnical Engineering Design Projects

– Bearing Capacity: Shallow and Deep

Foundation

– Earth Pressure - Retaining Walls

– Slope Stability

– Geosynthetic Design

• Geo-Environmental Engineering

• 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.

Geotechnical Design

Foundation Systems

• Designing of Shallow Foundation Systems – Differential Settlements

• “Canada's Leaning Tower or the "Kissing Silos”

(from Sharma 2003)

Foundation Systems

Deep Foundation Systems: Driven Piles

Foundation Systems

Deep Foundation Systems: Drilled Shafts

Earth Pressure and Retaining Walls

• Designing of retaining walls

Reinforced Earth

(from BECC Engineering 2001)

Earth Pressure and Retaining Walls

• Reinforced Earth Walls

(The Reinforced Wall Company 2003)

Earth Pressure and Retaining Walls

• Sheet Piles

(Boulanger and Duncan 2003)

Retaining Structure Systems

• Gabions

(Gaviones LEMAC (2003)

Retaining Structure Systems

• Tie-backs

(Boulanger and Duncan 2003)

Retaining Structure Systems

• Excavation Support Systems

(Boulanger and Duncan 2003)

Geosynthetics

• Geosynthetic stabilized walls

(Environmental Science & Engineering 2007) (kshitija.wordpress.com 2007)

Soil Improvement

• Stone Columns

(Boulanger and Duncan 2003)

Soil Improvement

• Jet Grouting

(Boulanger and Duncan 2003)

Soil Improvement

• Compaction Grouting

(Boulanger and Duncan 2003)

Soil Improvement

• Chemical Injection

(Boulanger and Duncan 2003)

Geo-Environmental Engineering

• Characterization and remediation of Geo-

environmental hazards

(from Willmer 2001)

Municipal Solid Waste (MSW) Landfill

(from Norwegian Geotechnical Institute 2001)