Foundation Engineering for Expansive Soils E-Book

John D. Nelson

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 577

Veröffentlichungsjahr: 2015

Beschreibung

Your guide to the design and construction of foundations on expansive soils Foundation Engineering for Expansive Soils fills a significant gap in the current literature by presenting coverage of the design and construction of foundations for expansive soils. Written by an expert author team with nearly 70 years of combined industry experience, this important new work is the only modern guide to the subject, describing proven methods for identifying and analyzing expansive soils and developing foundation designs appropriate for specific locations. Expansive soils are found worldwide and are the leading cause of damage to structural roads. The primary problem that arises with regard to expansive soils is that deformations are significantly greater than in non-expansive soils and the size and direction of the deformations are difficult to predict. Now, Foundation Engineering for Expansive Soils gives engineers and contractors coverage of this subject from a design perspective, rather than a theoretical one. Plus, they'll have access to case studies covering the design and construction of foundations on expansive salts from both commercial and residential projects. * Provides a succinct introduction to the basics of expansive soils and their threats * Includes information on both shallow and deep foundation design * Profiles soil remediation techniques, backed-up with numerous case studies * Covers the most commonly used laboratory tests and site investigation techniques used for establishing the physical properties of expansive soils If you're a practicing civil engineer, geotechnical engineer or contractor, geologist, structural engineer, or an upper-level undergraduate or graduate student of one of these disciplines, Foundation Engineering for Expansive Soils is a must-have addition to your library of resources.

Leseprobe

Table of Contents

Title Page

Copyright

Preface

List of Symbols

List of Abbreviations

Chapter 1: Introduction

1.1 Purpose

1.2 Organization

1.3 Terminology

References

Chapter 2: Nature of Expansive Soils

2.1 Microscale Aspects of Expansive Soil Behavior

2.2 Macroscale Aspects of Expansive Soil Behavior

2.3 Identification of Expansive Soils

2.4 Characteristics of Expansive Soil Profiles

References

Chapter 3: Site Investigation

3.1 Program of Exploration

3.2 Forensic Investigation

References

Chapter 4: Soil Suction

4.1 Soil Suction Components

4.2 Soil Water Characteristic Curve

4.3 Measurement of Matric Suction

4.4 Measurement of Osmotic Suction

4.5 Measurement of Total Suction

References

Chapter 5: State of Stress and Constitutive Relationships

5.1 State of Stress and Stress State Variables

5.2 Stress–Volume Relationships

5.3 Stress–Water Relationships

References

Chapter 6: Oedometer Testing

6.1 Consolidation-Swell and Constant Volume Tests

6.2 Correction of Oedometer Test Data

6.3 Relationship Between CS and CV Swelling Pressures (the

m

Method)

6.4 Factors Influencing Oedometer Test Results

References

Chapter 7: Water Migration in Expansive Soils

7.1 Water Flow in Unsaturated Soils

7.2 Depth and Degree of Wetting

7.3 Determination of Final Water Content Profiles for Design

7.4 Challenges in Water Migration Modeling for Expansive Soils

References

Chapter 8: Computation of Predicted Heave

8.1 Oedometer Methods

8.2 Soil Suction Methods

8.3 Empirical Methods

8.4 Progression of Heave with Time

8.5 Free-Field Surface Movement for Shrink–Swell Soils

8.6 Discussion of Heave Prediction

References

Chapter 9: General Considerations for Foundation and Floor Design

9.1 Risk and Life Cycle Costs

9.2 Foundation Alternatives

9.3 Factors Influencing Design of Structures on Expansive Soils

9.4 Remedial Measures

References

Chapter 10: Soil Treatment and Moisture Control

10.1 Overexcavation and Replacement

10.2 Prewetting Method

10.3 Chemical Admixtures

10.4 Moisture Control Alternatives

10.5 Summary of Soil Treatment Methods

References

Chapter 11: Design Methods for Shallow Foundations

11.1 Spread Footing Foundations

11.2 Stiffened Slab Foundations

11.3 Remedial Measures for Shallow Foundations

References

Chapter 12: Design Methods for Deep Foundations

12.1 Pier and Grade Beam Foundation

12.2 Patented Piers

12.3 Deep Foundation Design Examples

12.4 Remedial Measures for Deep Foundations

References

Chapter 13: Floors and Exterior Flatwork

13.1 Slabs-on-Grade

13.2 Stiffened Slabs

13.3 Structural Floors

13.4 Exterior Slabs and Flatwork

13.5 Remediation Techniques

References

Chapter 14: Lateral Pressure on Earth Retaining Structures

14.1 Computation of Lateral Pressure from Expansive Soils

14.2 Testing for Measuring Lateral Swelling Pressure

14.3 Reduction of Lateral Swelling Pressure

14.4 Design for Lateral Earth Pressure

References

Index

End User License Agreement

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Guide

Cover

Table of Contents

Preface

Begin Reading

List of Illustrations

Figure 2.1

Figure 2.2

Figure 2.3

Figure 2.4

Figure 2.5

Figure 2.6

Figure 2.7

Figure 2.8

Figure 2.9

Figure 2.10

Figure 2.11

Figure 2.12

Figure 2.13

Figure 2.14

Figure 2.15

Figure 2.16

Figure 2.17

Figure 2.18

Figure 2.19

Figure 2.20

Figure 2.21

Figure 2.22

Figure 2.23

Figure 2.24

Figure 2.25

Figure 2.26

Figure 2.27

Figure 3.1

Figure 3.2

Figure 3.3

Figure 4.1

Figure 4.2

Figure 4.3

Figure 4.4

Figure 4.5

Figure 4.6

Figure 4.7

Figure 4.8

Figure 4.9

Figure 4.10

Figure 4.11

Figure 4.12

Figure 4.13

Figure 4.14

Figure 4.15

Figure 4.16

Figure 4.17

Figure 4.18

Figure 4.19

Figure 4.20

Figure 4.21

Figure 4.22

Figure 4.23

Figure 4.24

Figure 4.25

Figure 5.1

Figure 5.2

Figure 6.1

Figure 6.2

Figure 6.3

Figure 6.4

Figure 6.5

Figure 6.6

Figure 6.7

Figure 6.8

Figure 6.9

Figure 6.10

Figure 6.11

Figure 6.12

Figure 6.13

Figure E6.1

Figure 7.1

Figure 7.2

Figure 7.3

Figure 7.4

Figure 7.5

Figure 7.6

Figure 7.7

Figure 7.8

Figure 7.9

Figure 7.10

Figure 7.11

Figure 8.1

Figure 8.2

Figure 8.3

Figure 8.4

Figure 8.5

Figure 8.6

Figure E8.1.1

Figure E8.1.2

Figure E8.4.1

Figure E8.4.2

Figure E8.4.3

Figure E8.5

Figure E8.6.1

Figure E8.6.2

Figure E8.6.3

Figure 9.1

Figure 9.2

Figure 9.3

Figure 9.4

Figure 9.5

Figure 9.6

Figure 9.7

Figure 10.1

Figure 10.2

Figure 10.3

Figure 10.4

Figure 10.5

Figure 11.1

Figure 11.2

Figure 11.3

Figure 11.4

Figure 11.5

Figure 11.6

Figure 11.7

Figure 12.1

Figure 12.2

Figure 12.3

Figure 12.4

Figure 12.5

Figure 12.6

Figure 12.7

Figure 12.8

Figure 12.9

Figure 12.10

Figure 12.11

Figure 12.12

Figure 12.13

Figure 12.14

Figure E12.2

Figure E12.3

Figure 13.1

Figure 13.2

Figure 13.3

Figure 13.4

Figure 13.5

Figure 13.6

Figure 13.7

Figure 13.8

Figure 14.1

Figure E14.1

Figure E14.2

List of Tables

Table 2.1

Table 2.2

Table 2.3

Table 2.4

Table 2.5

Table 2.6

Table 2.7

Table 4.1

Table 4.2

Table 4.3

Table 4.4

Table 4.5

Table 6.1

Table E6.1

Table E6.2

Table 7.1

Table E7.1

Table E7.2

Table 7.3

Table E8.1

Table E8.3.1

Table E8.3.2

Table E8.3.3

Table E8.4.1

Table E8.4.2

Table 8.1

Table E8.5

Table 8.2

Table 9.1

Table 9.2

Table 9.3

Table 9.4

Table 9.5

Table 9.6

Table 9.7

Table 9.8

Table 9.9

Table 9.10

Table 9.11

Table 9.12

Table 9.13

Table 9.14

Table 9.15

Table E10.1

Table 10.1

Table 10.2

Table 10.3

Table E11.1.1

Table E11.1.2

Table E11.2.1

Table E11.2.2

Table 11.1

Table 12.1

Table E12.1

Table 13.1

Foundation Engineering for Expansive Soils

John D. Nelson

Kuo Chieh (Geoff) Chao

Daniel D. Overton

Erik J. Nelson

Cover image: Adrian Morgan

Cover design: Cracked wall © man_kukuku/Thinkstock; all other images courtesy Engineering Analytics, Inc.

This book is printed on acid-free paper.

Copyright © 2015 by John Wiley & Sons, Inc. All rights reserved

Published by John Wiley & Sons, Inc., Hoboken, New Jersey

Published simultaneously in Canada

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Library of Congress Cataloging-in-Publication Data:

Nelson, John D.

Foundation engineering for expansive soils / John D. Nelson [and 3 others].

1 online resource.

Includes index.

Description based on print version record and CIP data provided by publisher; resource not viewed.

ISBN 978-1-118-41799-7 (pdf) – ISBN 978-1-118-41529-0 (epub) – ISBN 978-0-470-58152-0 (hardback)

1. Soil-structure interaction. 2. Swelling soils. 3. Foundations. I. Title.

TA711.5

624.1′51–dc23

2014043883

Preface

The practice of foundation engineering was first developed to address problems associated with settlement due to saturated soils that were prevalent in areas with soft coastal and deltaic deposits. As population and business centers moved into areas with more arid climates, problems with other types of soils became evident. Some soils that were capable of supporting a load in a natural unsaturated state were observed to either expand or collapse when wetted. These soils did not conform to the classical theories of soil mechanics and foundation engineering, and more research began to focus on the behavior of unsaturated soils.

Within the general category of unsaturated soils, the expansive soils posed the greatest problems, and created the most financial burden. In response to major infrastructure development in the late 1950s and 1960s there was an upswing in research regarding the identification of expansive soils and factors influencing their behavior. Engineers became more cognizant of the need for special attention to the unique nature of expansive soils.

The general curricula taught at universities did not specifically address the design of foundations for these soils, and engineers did not become aware of expansive soils unless they began to practice in areas where those soils existed. Therefore, the practice of foundation engineering for expansive soils developed around experience and empirical methods.

Few books have been written specifically on the subject of design of foundations on expansive soils. Fu Hua Chen wrote a book entitled Foundations on Expansive Soils that was published in 1975. A second edition of that book was published in 1988. Those books were based to a large extent on Mr. Chen's personal experiences along the Front Range of Colorado. The Department of the Army published a technical manual in 1983 titled, Foundations for Expansive Soils. That manual served as the basis for the design of structures on military bases, and was available to the civilian engineering community as well.

At about that same time the US National Science Foundation funded a research project at Colorado State University (CSU) dealing with expansive soils. The scope of that project included a survey of the practices followed by engineers throughout the United States and Canada, as well as individuals from other countries. On the basis of that survey, and research that had been conducted by that time, Nelson and Miller (1992) published a book entitled Expansive Soils: Problems and Practices in Foundation and Pavement Engineering.

In 1993 Fredlund and Rahardjo published their text, Soil Mechanics for Unsaturated Soil. That book extended the framework of classical soil mechanics to incorporate soil suction as an independent stress state variable, and provided the rigor needed for a theoretical understanding of unsaturated soils. A part of that book was devoted to the mechanics of expansive soil.

In the 20 years since the publication of Nelson and Miller (1992), the authors of this book have worked together and have performed hundreds of forensic investigations on expansive soils. In the course of that work, many new ideas have emerged, additional research has been conducted, and methods of analyses were developed that have been applied to foundation design. This book reflects the authors' experiences over the period since the book by Nelson and Miller was written. It incorporates a broader scope of analysis and a greater degree of rigor than the earlier work.

In a presentation at the 18th International Conference on Soil Mechanics and Geotechnical Engineering in which he introduced his most recent book, Unsaturated Soil Mechanics in Engineering Practice, Dr. Fredlund noted the need for practitioners to continue to publish works that will extend the application of the concepts of unsaturated soil mechanics to the solution of practical geotechnical engineering problems. It is believed that this book responds to that call and will provide a sound basis on which to establish a practice of foundation engineering for expansive soils.

Many people have contributed to the completion of this book, most notably Ms. Georgia A. Doyle. She has read the entire manuscript, provided necessary and valuable editing and coordination, and queried the authors where material was not clear. Many valuable comments were received from Dr. Donald D. Runnells after his review of chapter 2, and Dr. Anand J. Puppala after his review of chapter 10. Professor Erik. G. Thompson developed the FEM analysis for the APEX program presented in chapter 12.

In addition, many current and former staff of the authors' company, Engineering Analytics, Inc., have contributed in one way or another. Special recognition goes to Kristle Beaudet, Todd Bloch, Denise Garcia, Debbie Hernbloom, Jong Beom Kang, Lauren Meyer, Ronald Pacella, and Rob Schaut. Their help along the way is much appreciated.

John D. NelsonKuo Chieh (Geoff) ChaoDaniel D. OvertonErik J. Nelson

List of Symbols

A

c

clay activity

B

width of footing

B

slope of matric suction vs water content curve

c

cohesion of soil

C

molar concentration

C

c

compression index

C

DA

“Department of Army” heave index

C

H

heave index

C

h

suction compression index

C

m

matric suction index

C

p

peak cohesion

C

r

residual cohesion

C

s

swelling index

C

t

compression index with respect to net normal stress

C

w

CLOD index

C

(ψ)

correction function

d

distance between particles

d

pier shaft diameter

D

constrained modulus of soil

D

0

depth of nonexpansive fill

e

void ratio

e

base of natural logarithm, 2.71828

e

0

initial void ratio

E

s

Young's modulus of the soil

E

A

Young's modulus of the soil in units of bars

f

lateral restraint factor

f

s

anchorage skin friction

f

u

uplift skin friction

F

t

nodal force tangent to pier

F

t

maximum interior tensile force

g

gravitational acceleration

G

s

specific gravity of solids

h

pressure head

h

d

displacement pressure head

h

m

matric suction head

h

o

osmotic pressure head

H

thickness of a layer of soil

Δ

H

change in thickness of that layer due to heave

H

t

total hydraulic head

i

hydraulic head gradient

I

pt

instability index

I

ss

shrink swell index

k

spring constant in APEX

K

a

active earth pressure

K

(

h

)

coefficient of unsaturated hydraulic conductivity

K

0

coefficient of earth pressure at rest

K

p

passive earth pressure

K

s

coefficient of permeability

L

length of pier

L

reqd

required pier length

LL

liquid limit

Δ

L

/Δ

L

D

linear strain relative to dry dimensions

m

molality

m

factor for swelling pressure correlation

n

porosity of the soil

p

a

active earth pressure

pF

unit for soil suction

p

0

equivalent fluid pressure

p

p

passive earth pressure

P

partial pressure of pore water vapor

P

load per linear dimension

P

footing load

P

/

P

0

relative humidity

P

dl

dead load on footing

PI

plasticity index

PL

plastic limit

P

max

maximum tensile force

P

0

saturation pressure of water vapor over a flat surface of pure water at the same temperature

P

0

total load due to earth pressure

q

flow rate of water

q

distributed load

q

a

allowable bearing pressure

q

u

unconfined compressive strength

q

m

mean rate of infiltration at the ground surface

r

radius

r

2

correlation coefficient

r

w

sources or sinks of water

R

universal gas constant

R

resistance force

RF

risk factor

RF

w

weighted risk factor

R

p

pullout capacity of helical bearing plate

s

coefficient for load effect on heave

S

degree of saturation

%

SP

percent of swelling pressure that is applied by the total applied stress on the soil

T

absolute temperature

T

s

surface tension

u

a

pore air pressure

(

u

a

)

d

displacement air entry pressure

u

w

pore water pressure

U

total uplift force

U

t

nodal displacement tangent to pier

V

molar volume of a solution

V

total volume of soil

Δ

V/V

volumetric strain

V

w

volume of water in an element of soil

w

gravimetric water content

w

aev

air entry gravimetric water content

w

u

gravimetric water content corresponding to a suction of 1 kPa

w

e

weight of sample at equilibrium

w

s

weight of oven-dry sample

y

max

differential soil movement

y

s

net ground surface movement

z

depth

z

elevation head

z

soil layer thickness

z

A

depth of active zone

z

AD

depth of design active zone

z

p

depth of potential heave

z

s

zone of seasonal moisture fluctuation

z

w

zone (depth) of wetting

z

wt

height above the water table

Δ

z

thickness of soil layer

α

compressibility factor

α

soil to pier adhesion factor

α

drainage slope

α

1

coefficient of uplift between the pier and the soil

α

2

coefficient of anchorage between the pier and the soil

β

contact angle with tube

β

reduction factor for expansive earth pressure

γ

unit weight of soil

γ

d

dry density of soil

γ

sat

saturated unit weight of soil

γ

t

total unit weight of soil

γ

w

unit weight of water

γ

ψo

osmotic suction volumetric compression index

γ

σ

mean principal stress volumetric compression index

γ

ψm

matric suction volumetric compression index

δ

interface friction angle

δ

max

differential heave

strain

iso

isotropic swelling strain

s

strain

sn

shrinking strain

sw

swelling strain

T

total range of strain

s%

percent swell

s%N

normalized percent swell

s%vo

percent swell measured from a sample inundated at the overburden stress in the consolidation-swell test

θ

volumetric water content

θ

f

volumetric water content above the wetting front

θ

r

residual volumetric water content

θ

s

saturated volumetric water content

λ

pore size distribution index

ν

number of ions from one molecule of salt

ν

Poisson's ratio

ρ

heave

Δρ

differential movement

ρ

max

maximum heave

ρ

0

free-field heave

ρ

p

pier heave

ρ

s

solute mass/density

ρ

ult

total heave

σ = (σ′ +

u

w

)

total stress, normal stress

σ′ = (σ –

u

w

)

effective stress

σ″ = (σ –

u

a

)

net normal stress

consolidation-swell swelling pressure

constant volume swelling pressure

reduced swelling pressure

σ

ext

external stress

final vertical stress

lateral stress

inundation stress

σ

int

internal stress between particles

Δ

increment of applied stress

σ

vo

, ,

vertical overburden stress in terms of total, effective, or net normal stress

τ

shear stress

φ

osmotic coefficient

φ

angle of internal friction

φ

p

peak angle of internal friction

φ

r

residual angle of internal friction

χ

chi parameter

ψ

total suction

ψ

ae

air entry soil suction

ψ

m

= (u

a

- u

w

)

matric suction

ψ

o

osmotic suction

ψ

r

residual suction

List of Abbreviations

APEX

analysis of piers in expansive soils

ANN

artificial neural network

CEAc = CEC/clay content

cation exchange capacity activity

CEC

cation exchange capacity

CNS

cohesive non-swelling

COLE

coefficient of linear extensibility

CS

consolidation-swell

CV

constant volume

DTA

differential thermal analysis

EI

expansion index

ET

evapotranspiration

FSI

free swell index

LE

linear extensibility

LMO

lime modification optimum

PVC

potential volume change

PVC

polyvinyl chloride

PVR

potential vertical rise

SAMC

standard absorption moisture content

SI

shrinkage index

SL

shrinkage limit

SSA

specific surface area

SWCC

soil water characteristic curve

SWCR

soil water characteristic relationship

TP

total potassium

UV

ultraviolet

XRD

X-ray diffraction