Soil Mechanics Fundamentals and Applications Second Edition Isao Ishibashi

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Soil Mechanics Fundamentals and Applications Second Edition Isao Ishibashi

Contents

Preface to the First Edition………………………………………………………………………….xvii
Preface to the Second Edition……………………………………………………………………….xix
The Authors……………………………………………………………………………………………. xxiii
Chapter 1 Introduction……………………………………………………………………………..1
1.1 Soil Mechanics and Related Fields………………………………………1
1.2 Biography of Dr. Karl von Terzaghi…………………………………….1
1.3 Uniqueness of Soils…………………………………………………………..4
1.4 Approaches to Soil Mechanics Problems……………………………..4
1.5 Examples of Soil Mechanics Problems………………………………..5
1.5.1 Leaning Tower of Pisa……………………………………………5
1.5.2 Sinking of Kansai International Airport…………………..5
1.5.3 Liquefaction—Sand Becomes Liquid during
Earthquake…………………………………………………………..7
References…………………………………………………………………………………8
Chapter 2 Physical Properties of Soils……………………………………………………….9
2.1 Introduction……………………………………………………………………..9
2.2 Origin of Soils………………………………………………………………….9
2.3 Soil Particle Shapes………………………………………………………… 10
2.4 Definitions of Terms with Three-Phase Diagram……………….. 12
2.5 Particle Size and Gradation……………………………………………… 18
2.6 Summary……………………………………………………………………….24
References……………………………………………………………………………….24
Problems………………………………………………………………………………….24
Chapter 3 Clays and Their Behavior………………………………………………………..29
3.1 Introduction……………………………………………………………………29
3.2 Clay Minerals…………………………………………………………………29
3.2.1 Kaolinite Clay…………………………………………………….30
3.2.2 Montmorillonite Clay…………………………………………..30
3.2.3 Illite Clay…………………………………………………………… 33
3.3 Clay Shapes and Surface Areas…………………………………………34
3.4 Surface Charge of Clay Particles………………………………………. 35
3.5 Clay–Water Systems……………………………………………………….. 35
3.6 Interaction of Clay Particles……………………………………………..37
3.6.1 Van der Waal’s Force (Attractive)………………………….38
3.6.2 Dipole–Cation–Dipole Attraction………………………….38
3.6.3 Cation Linkage (Attractive)…………………………………..38
3.6.4 Cation–Cation Repulsive Force…………………………….38
3.6.5 Anion–Anion Repulsive Force………………………………38
3.7 Clay Structures……………………………………………………………….40
3.8 Atterberg Limits and Indices……………………………………………. 41
3.9 Activity…………………………………………………………………………. 45
3.10 Swelling and Shrinkage of Clays………………………………………46
3.11 Sensitivity and Quick Clay………………………………………………. 47
3.12 Clay Versus Sand…………………………………………………………….49
3.13 Summary……………………………………………………………………….50
References……………………………………………………………………………….50
Problems…………………………………………………………………………………. 51
Chapter 4 Soil Classification…………………………………………………………………… 53
4.1 Introduction…………………………………………………………………… 53
4.2 Unified Soil Classification System (USCS)………………………… 53
4.2.1 For G or S………………………………………………………….. 55
4.2.2 For C, M, O, or Pt………………………………………………..56
4.3 AASHTO Classification System………………………………………. 57
4.4 Summary………………………………………………………………………. 61
References………………………………………………………………………………. 62
Problems…………………………………………………………………………………. 62
Chapter 5 Compaction…………………………………………………………………………….65
5.1 Introduction……………………………………………………………………65
5.2 Relative Density………………………………………………………………65
5.3 Laboratory Compaction Test……………………………………………. 67
5.3.1 Standard Proctor Test Procedure…………………………… 67
5.3.2 Compaction Curve………………………………………………68
5.3.3 Zero Air Void Curve…………………………………………… 70
5.3.4 Compaction Energy…………………………………………….. 71
5.4 Specification of Compaction in the Field…………………………… 72
5.5 Field Compaction Methods……………………………………………… 74
5.5.1 Compaction Equipment……………………………………….. 74
5.5.2 Dynamic Compaction…………………………………………. 76
5.6 Field Density Determinations……………………………………………77
5.6.1 Sand Cone Method………………………………………………77
5.6.2 Other Field Density Methods………………………………..80
5.7 California Bearing Ratio Test…………………………………………..80
5.8 Summary………………………………………………………………………. 81
References……………………………………………………………………………….82
Problems………………………………………………………………………………….82
Chapter 6 Flow of Water through Soils…………………………………………………….85
6.1 Introduction……………………………………………………………………85
6.2 Hydraulic Heads and Water Flow………………………………………85
6.3 Darcy’s Equation…………………………………………………………….87
6.4 Coefficient of Permeability……………………………………………….89
6.4.1 Hazen’s Formula………………………………………………….89
6.4.2 Chapuis’s Formula……………………………………………….90
6.4.3 Kozeny and Carman’s Formula……………………………..90
6.5 Laboratory Determination of Coefficient of Permeability……. 91
6.5.1 Constant Head Permeability Test………………………….. 91
6.5.2 Falling Head Permeability Test……………………………..92
6.6 Field Determination of Coefficient of Permeability……………..93
6.6.1 Unconfined Permeable Layer Underlain by
Impervious Layer………………………………………………..94
6.6.2 Confined Aquifer…………………………………………………94
6.7 Flow Net………………………………………………………………………..95
6.7.1 One-Dimensional Flow Net………………………………….95
6.7.2 Flow Net for Two-Dimensional Problems with
Isotropic Soils……………………………………………………..97
6.7.3 Pressure Heads in Flow Net………………………………….99
6.8 Boundary Water Pressures…………………………………………….. 100
6.9 Summary…………………………………………………………………….. 106
References…………………………………………………………………………….. 106
Problems……………………………………………………………………………….. 106
Chapter 7 Effective Stress……………………………………………………………………… 111
7.1 Introduction…………………………………………………………………. 111
7.2 Total Stress versus Effective Stress…………………………………. 111
7.3 Effective Stress Computations in Soil Mass…………………….. 111
7.3.1 Dry Soil Layers………………………………………………… 112
7.3.2 Soil Layers with Steady Water Table…………………… 113
7.3.3 Totally Submerged Soil Layers…………………………… 115
7.4 Effective Stress Change Due to Water Table Change………… 116
7.5 Capillary Rise and Effective Stress…………………………………. 117
7.6 Effective Stress with Water Flow……………………………………. 120
7.7 Quicksand (Sand Boiling)……………………………………………… 122
7.8 Heave of Clay Due to Excavation…………………………………….124
7.8.1 Dry Excavation………………………………………………….124
7.8.2 Wet Excavation…………………………………………………. 125
7.9 Summary…………………………………………………………………….. 127
References…………………………………………………………………………….. 127
Problems……………………………………………………………………………….. 127
Chapter 8 Stress Increments in Soil Mass……………………………………………… 135
8.1 Introduction…………………………………………………………………. 135
8.2 2:1 Approximate Slope Method………………………………………. 135
8.3 Vertical Stress Increment Due to a Point Load…………………. 137
8.4 Vertical Stress Increment Due to a Line Load………………….. 140
8.5 Vertical Stress Increment Due to a Strip Load………………….. 141
8.6 Vertical Stress Increment under a Circular Footing…………… 145
8.7 Vertical Stress Increment under an Embankment Load……… 146
8.8 Vertical Stress Increment under Corner of Rectangular
Footing………………………………………………………………………… 150
8.9 Vertical Stress Increment under Irregularly Shaped
Footing…………………………………………………………………….154
8.10 Summary…………………………………………………………………….. 157
References…………………………………………………………………………….. 157
Problems……………………………………………………………………………….. 157
Chapter 9 Settlements…………………………………………………………………………… 163
9.1 Introduction…………………………………………………………………. 163
9.2 Elastic Settlements………………………………………………………… 163
9.3 Primary Consolidation Settlement………………………………….. 166
9.4 One-Dimensional Primary Consolidation Model……………… 166
9.5 Terzaghi’s Consolidation Theory……………………………………. 167
9.6 Laboratory Consolidation Test……………………………………….. 176
9.7 Determination of Cv……………………………………………………… 177
9.7.1 Log t Method……………………………………………………. 177
9.7.2 t Method……………………………………………………….. 178
9.8 e-log σ Curve……………………………………………………………….. 179
9.9 Normally Consolidated and Overconsolidated Soils…………. 182
9.10 Final Consolidation Settlement for Thin Clay Layer…………. 185
9.10.1 Normally Consolidated Soils……………………………… 185
9.10.2 Overconsolidated Soils………………………………………. 187
9.11 Consolidation Settlement for Multilayers or a Thick
Clay Layer…………………………………………………………………… 188
9.12 Summary of Primary Consolidation Computations…………… 191
9.12.1 The “How Much” Problem…………………………………. 191
9.12.2 The “How Soon” Problem (Rate Problem)…………… 192
9.13 Secondary Compression………………………………………………… 192
9.14 Allowable Settlement…………………………………………………….. 194
9.15 Ground-Improving Techniques against Consolidation
Settlement……………………………………………………………………. 195
9.15.1 Vertical Drain (Paper Drain, Wick Drain,
and Sand Drain) Techniques………………………………. 196
9.15.2 Preloading Technique………………………………………… 197
9.15.3 Vacuum Consolidation Technique……………………….. 197
9.16 Summary…………………………………………………………………….. 198
References…………………………………………………………………………….. 198
Problems……………………………………………………………………………….. 199
Chapter 10 Mohr’s Circle in Soil Mechanics…………………………………………….207
10.1 Introduction………………………………………………………………….207
10.2 Concept of Mohr’s Circle……………………………………………….207
10.3 Stress Transformation…………………………………………………….207
10.4 Mohr’s Circle Construction……………………………………………. 211
10.5 Sign Convention of Shear Stress…………………………………….. 213
10.6 Pole (Origin of Planes) of Mohr’s Circle………………………….. 214
10.7 Summary of Usage of Mohr’s Circle and Pole………………….. 218
10.8 Examples of Usage of Mohr’s Circle and Pole in
Soil Mechanics…………………………………………………………….. 218
10.8.1 Shear Failure Direction on Soil Specimen……………. 218
10.8.2 Failure Zone in Rankine’s Lateral Earth
Pressure Theory……………………………………………….. 219
10.9 Summary……………………………………………………………………..220
Reference……………………………………………………………………………….220
Problems………………………………………………………………………………..220
Chapter 11 Shear Strength of Soils………………………………………………………….225
11.1 Introduction………………………………………………………………….225
11.2 Failure Criteria……………………………………………………………..225
11.3 Direct Shear Test…………………………………………………………..228
11.4 Unconfined Compression Test…………………………………………230
11.5 Triaxial Compression Test……………………………………………… 232
11.5.1 General Concept and Test Setup…………………………. 232
11.5.2 Initial Consolidation Process and Drainage
Condition during Shear……………………………………… 235
11.5.3 Consolidated Drained (CD) Triaxial Test……………..236
11.5.4 Consolidated Undrained (CU) Triaxial Test
with Pore Water Pressure Measurement……………….238
11.5.5 Effective Stress Parameters from CU and
CD Tests……………………………………………………….242
11.5.6 Unconsolidated Undrained (UU) Test…………………. 243
11.6 Other Shear Test Devices……………………………………………….244
11.6.1 Vane Shear Device…………………………………………….244
11.6.2 Tor-Vane Shear Test……………………………………………245
11.6.3 Pocket Penetrometer…………………………………………..245
11.7 Summary of Strength Parameters for Saturated Clays……….246
11.7.1 UU Test…………………………………………………………… 247
11.7.2 CD Test and CU Test (Effective Stress)……………….. 247
11.7.3 CU Test (Total Stress)……………………………………….. 247
11.8 Applications of Strength Parameters from CD, CU,
and UU Tests to In-Situ Cases…………………………………………248
11.8.1 Construction of Embankment on Soft Clay
Soil at Once (UU Case)………………………………………248
11.8.2 Foundation Design for Rapidly Constructed
Superstructures………………………………………………….248
11.8.3 Staged Construction of Embankment on Soft
Clay (CU Case)………………………………………………….248
11.8.4 Stability of Cut Slope (CD Case)………………………….249
11.9 Strength Parameters for Granular Soils……………………………250
11.10 Direction of Failure Planes on Sheared Specimen…………….. 252
11.11 Summary…………………………………………………………………….. 255
References…………………………………………………………………………….. 255
Problems……………………………………………………………………………….. 255
Chapter 12 Lateral Earth Pressure…………………………………………………………. 261
12.1 Introduction…………………………………………………………………. 261
12.2 At-Rest, Active, and Passive Pressures…………………………….. 261
12.3 At-Rest Earth Pressure………………………………………………….. 262
12.3.1 Elastic Solution………………………………………………….263
12.3.2 Empirical Formulae…………………………………………..263
12.4 Rankine’s Lateral Earth Pressure Theory…………………………265
12.4.1 Active Case……………………………………………………….265
12.4.2 Passive Case……………………………………………………..268
12.4.3 Summary of Rankine’s Pressure Distributions……… 271
12.5 Coulomb’s Earth Pressure……………………………………………… 276
12.5.1 Active Case………………………………………………………. 276
12.5.2 Passive Case……………………………………………………..277
12.5.3 Coulomb’s Lateral Pressure Distribution……………… 279
12.6 Lateral Earth Pressure Due to Surcharge Load………………… 281
12.6.1 Due to Infinitely Long Uniform Surcharge Load….. 281
12.6.2 Due to Point Load (Non-Yielding Wall)……………….. 281
12.6.3 Due to Line Load (Non-Yielding Wall)………………..282
12.6.4 Due to Strip Load (Non-Yielding Wall)………………..283
12.7 Coulomb, Rankine, or Other Pressures?…………………………..285
12.8 Summary……………………………………………………………………..288
References……………………………………………………………………………..288
Problems………………………………………………………………………………..288
Chapter 13 Site Exploration……………………………………………………………………. 295
13.1 Introduction…………………………………………………………………. 295
13.2 Site Exploration Program………………………………………………. 295
13.3 Geophysical Methods…………………………………………………….297
13.3.1 Ground Penetration Radar Survey……………………….297
13.3.2 Seismic Surveys………………………………………………..297
13.4 Borehole Drilling…………………………………………………………..299
13.4.1 Number of Borings…………………………………………….299
13.4.2 Depth of Boreholes…………………………………………….300
13.5 Standard Penetration Test……………………………………………….300
13.6 Undisturbed Soil Samplers……………………………………………..303
13.7 Groundwater Monitoring………………………………………………..305
13.8 Cone Penetration Test…………………………………………………….305
13.9 Other In-Situ Tests…………………………………………………………308
13.9.1 Vane Shear Test…………………………………………………308
13.9.2 Pressuremeter Test……………………………………………..308
13.9.3 Dilatometer Test………………………………………………..308
13.10 Summary……………………………………………………………………..309
References…………………………………………………………………………….. 310
Chapter 14 Bearing Capacity and Shallow Foundations…………………………… 311
14.1 Introduction…………………………………………………………………. 311
14.2 Terzaghi’s Bearing Capacity Theory……………………………….. 311
14.3 Generalized Bearing Capacity Equation………………………….. 312
14.3.1 Shape Factors fcs, fqs, fγs……………………………………… 313
14.3.2 Depth Factors fcd, fqd, fγd…………………………………….. 314
14.3.3 Inclination Factors fci, fqi, fγi……………………………….. 314
14.4 Correction Due to Water Table Elevation…………………………. 317
14.5 Gross versus Net Bearing Capacity…………………………………. 319
14.6 Factor of Safety on Bearing Capacity……………………………… 320
14.6.1 F.S. for Gross Bearing Capacity………………………….. 320
14.6.2 F.S. for Strength Parameters……………………………….. 321
14.7 Shallow Foundation Design……………………………………………. 321
14.7.1 Footing Depth…………………………………………………… 321
14.7.2 Design Method…………………………………………………. 322
14.8 Summary……………………………………………………………………..324
References……………………………………………………………………………..324
Problems………………………………………………………………………………..324
Chapter 15 Deep Foundations…………………………………………………………………. 327
15.1 Introduction…………………………………………………………………. 327
15.2 Types of Piles………………………………………………………………. 327
15.3 Load Carrying Capacity by Static Analytical Methods……… 327
15.3.1 Tip Area Ap and Perimeter of Pile “p”…………………. 330
15.4 Static Pile Capacity on Sandy Soils………………………………… 333
15.4.1 Tip Resistance………………………………………………….. 333
15.4.2 Skin Friction Resistance…………………………………….. 333
15.5 Static Pile Capacity in Cohesive Soils……………………………… 336
15.5.1 Tip Resistance………………………………………………….. 336
15.5.2 Skin Frictional Resistance………………………………….. 337
15.6 Other Methods of Pile Capacity Estimation……………………… 343
15.6.1 Pile Capacity from SPT and CPT Data…………………344
15.6.2 Pile Load Test……………………………………………………346
15.6.3 Pile Driving Formula…………………………………………349
15.6.4 Dynamic Pile Analysis………………………………………. 350
15.7 Negative Skin Friction…………………………………………………… 351
15.8 Group Pile……………………………………………………………………. 351
15.9 Consolidation Settlement of Group Piles…………………………. 354
15.10 Pullout Resistance………………………………………………………… 357
15.11 Summary…………………………………………………………………….. 357
References…………………………………………………………………………….. 357
Problems……………………………………………………………………………….. 358
Chapter 16 Slope Stability………………………………………………………………………. 363
16.1 Introduction…………………………………………………………………. 363
16.2 Slope Failure………………………………………………………………… 363
16.2.1 Slope Failure Modes………………………………………….. 363
16.2.2 Mechanism of Slope Failure………………………………. 363
16.2.3 Factor of Safety against Sliding…………………………..364
16.2.4 Factors of Slope Failure………………………………………365
16.2.4.1 Increases in Triggering Factors……………..366
16.2.4.2 Decreases in Resisting Factors………………366
16.2.5 Factor of Safety against Soil’s Strength………………..366
16.3 Slope Stability Analytical Methods…………………………………366
16.3.1 Limit Equilibrium Method…………………………………. 367
16.3.2 Short-Term and Long-Term Stability Analysis……… 367
16.4 Slope Stability of a Semi-infinitely Long Slope………………… 367
16.4.1 Dry Slope…………………………………………………………. 367
16.4.2 Slope under Steady Water Table…………………………..368
16.4.3 Slope with Water Flow Parallel to
Slope Direction………………………………………………371
16.4.3.1 Flow Surface at Slope Surface (h = z)……. 372
16.4.3.2 Flow Surface at Sliding Surface (h = 0)…….372
16.4.3.3 Flow Surface below Sliding Surface
with Consideration of Capillary
Rise (h < 0)………………………………………… 372
16.4.4 Slope with Horizontal Water Flow………………………. 372
16.4.5 Slope with Water Flow in θ Angle Direction
from Horizontal………………………………………………… 374
16.5 Stability Analysis for Circular Slip Surface……………………… 376
16.5.1 φ = 0 Materials (Cohesive Soils)…………………………. 376
16.5.2 c = 0 and φ Materials (Granular Soils)…………………. 377
16.5.3 c and φ Materials with Boundary Water Pressure…….379
16.5.4 Slice Method…………………………………………………….380
16.6 Analysis for Multiple Liner Sliding Surfaces……………………. 382
Contents xv
16.7 Stabilization for Unstable Slopes……………………………………..384
16.7.1 Change of Slope Shape……………………………………….384
16.7.2 Drainage of Water from Slope…………………………….384
16.7.3 Construction of Counterweight Berms…………………. 385
16.7.4 Retaining Wall Construction………………………………. 385
16.8 Summary…………………………………………………………………….. 385
References…………………………………………………………………………….. 385
Problems……………………………………………………………………………….. 386
Numerical Answers to Selected Problems…………………………………………………. 389

 

Preface to the First Edition

Soil Mechanics Fundamentals is written with the intention of providing a very
basic yet essential concept of soil mechanics to students and engineers who are learning
the fundamentals of soil mechanics for the first time. This book is meant mainly
for college students who have completed key engineering science courses such as
basic calculus, physics, chemistry, statistics, mechanics of solids, and engineering
materials and are ready to enter into one of the specialty areas of civil, architectural,
and geotechnical engineering. This book is intended to provide a thorough, fundamental
knowledge of soil mechanics in a simple and yet comprehensive way, based
on the students’ knowledge of the basic engineering sciences. Special emphasis is
placed on giving the reader an understanding of what soil is, how it behaves, why it
behaves that way, and the engineering significance of such behavior.
There are many books on soil mechanics, geotechnical engineering, and the
foundation engineering field. Through our experience in teaching introductory
soil mechanics courses to college students for more than 20 years, we have come
to realize that most of these textbooks either lack comprehensive explanations of
soil behavior or contain massive information without clear and organized contents.
We have always felt the need for a better introductory textbook for our students. For
us, the ideal first textbook on soil mechanics should be presented with a firm basis of
the knowledge of the engineering sciences. First, the varied behavior of soils should
be well explained, based on mathematics, physics, and chemistry in a simple and
yet comprehensive way. Second, the rather complex phenomena of soil mechanics
should be better organized and presented in a systematic way with a smooth flow
of information. Last, students who have finished the first course of soil mechanics
should be ready to apply the learned concepts to field applications such as foundation
engineering with a full comprehension of the fundamentals of soil behavior.
In other words, students should not simply memorize equations and numbers, but
also understand why and how soil mechanics works. We believe that only then will
students and engineers confidently face challenging situations in well-thought-out,
logical, and innovative ways.
This book was written in such a way that the preceding ideal introduction of
soil mechanics concepts can be approached as closely and as smoothly as possible.
For example, plasticity of soils is rather easily understood after learning clay minerals
and the interactions of clay and water. Similarly, the quicksand phenomenon in
front of sheet pile and heaving at the bottom of excavation come after flow of water
and effective stress concepts. Also, Mohr’s circle is presented just before the shear
strength and lateral earth pressure theory. At the same time, we intentionally avoided
including too much information in each subject area. The same holds true for the
presentation of equations. There are always exceptions and there are many empirical
correlations available in the field of soil mechanics. However, this book includes only
the essential ones to emphasize the importance of fundamentals.
xviii Preface to the First Edition
To summarize, this book is not meant to cover the full spectrum of the geotechnical
engineering discipline, but rather to provide the simplest yet most comprehensive
first textbook in soil mechanics for students and engineers in the field of civil engineering
as well as architecture to understand what soil is, how it works, and why it
works that way.

Preface to the Second Edition

The first edition of this book (Soil Mechanics Fundamentals) was published in
2010 with the aim to offer an introductory soil mechanics textbook to college students,
who for the first time would be exposed to this fascinating yet complex subject
area. The book was written with concise contents, yet with in-depth fundamental
principles on the subject. At the same time we tried to keep the cost of the book
affordable to the readers. The book has been well received all over the world, as
it explains soil’s fundamental behavior from basic engineering science knowledge
with carefully selected engineering practices and applications. Our original purpose
of the book has been accomplished and it has been well distributed around the world,
including a Japanese version published by Kyoritsu Publishing Company, Tokyo,
Japan. It has been adopted as a textbook in many institutions worldwide and has been
read by many practicing engineers.
On the other hand, we have received much input from the readers of the first
edition.
One of these suggestions was to expand the contents to include an introductory
foundation engineering section. We accepted this suggestion in order to
make the book a complete introductory geotechnical engineering book. Syllabuses
of many institutions cover the introductory foundation engineering concept after the
basic soil mechanics sections. This is our motivation for the second edition, Soil
Mechanics Fundamentals and Applications, and thus we kept the original first
12 chapters of soil mechanics without any major changes. Chapter 13 of the previous
edition was modified by adding the shallow foundation design section at the end,
and it became Chapter 14 (Bearing Capacity and Shallow Foundations) in this
new edition. Three new chapters on foundation-engineering-related topics have
been added: Chapter 13 (Site Exploration), Chapter 15 (Deep Foundations), and
Chapter 16 (Slope Stability).
Accordingly, the organization of the new edition of the book (which includes the
original 12 chapters) is as follows. Chapters and their contents are carefully placed
in an order so that the understanding level of the subject matter increases gradually
as we move from one chapter to another. Following the sequence presented in this
book is therefore recommended.
After the introductory Chapter 1 about soil mechanics, Chapter 2 (Physical
Properties of Soils) deals with the origin and the description of soils. The major terms
used in soil mechanics are defined by using the three-phase diagram. Soil shapes and
gradations are also discussed in this chapter. Chapter 3 (Clays and Their Behavior)
presents unique characteristics of clays from their mineral origins, sizes, shapes,
electrical properties, behavior in water, and interaction among particles. Based on
this knowledge, their plastic behavior, swelling, and shrinkage properties, sensitivity,
and quick clays are discussed.
Based on the information covered in Chapter 2 and Chapter 3, soil classifications by
the Unified Soil Classification System (also ASTM) and by the American Association
of State Highway and Transportation Officials (AASHTO) are presented in Chapter 4.
xx Preface to the Second Edition
Chapter 5 handles laboratory and field compaction techniques, including
description
of relative density and the CBR (California Bearing Ratio) method.
Chapter 6 presents the flow of water through soils. Definitions of various
hydraulic heads and the coefficient of permeability are presented, as well as the twodimensional
flow net technique, introduced from a simple one-dimensional water
flow mechanism without using the Laplace equation. Finally, a systematic method to
compute boundary water pressures is demonstrated.
In Chapter 7, the concept of effective stress and its applications to various
important
soil mechanics problems, including capillary rise, quicksand, and heave
at the bottom of an excavation, are discussed. The concept is later used in consolidation
theory (Chapter 9) and shear strength (Chapter 11).
Chapter 8 is a preparation chapter for Chapter 9 (Settlements). Stress increments
in a soil mass due to various types of footing load on the ground are presented. Most
of these solutions are based on Boussinesq’s elastic solution, and they are needed as
the major source of consolidation settlements in Chapter 9.
In Chapter 9, Terzaghi’s one-dimensional consolidation theory and its application
are presented. To simplify the discussions, the consolidation problems are categorized
into two parts: “how soon” (rate) problems and “how much” (amount of final
settlement) problems, so that readers can clearly avoid confusion while handling the
thickness (H or 2H) of the clay layer.
Chapter 10 deals with Mohr’s circle, which is utilized in chapters relating to shear
strength and lateral earth pressure. In particular, a clear definition of the shear stress
sign convention is made so that the concept of the pole of Mohr’s circle (the origin of
the planes) can be utilized effectively without any room for mistakes.
Chapter 11 is related to the shear strength of soils. Failure criteria are introduced,
and laboratory as well as field shear strength determination techniques are
presented. Clear definitions are presented on consolidated, unconsolidated, drained,
and undrained
shear strength parameters, and usages of these different shear strength
parameters are critically evaluated.
In Chapter 12, at-rest earth pressure and the classic Rankine and Coulomb active
and passive pressure theories are presented. These classic theories are critically
reviewed in terms of their assumptions and limitations, and appropriate applications of
the theories into practice are discussed.
Chapters 13 through 16 cover introductory foundation engineering. Chapter 13
is related to site exploration, which is needed prior to foundation design at given
sites. It includes a site exploration program, geophysical methods, borehole drilling
and sampling, and in-situ testing methods such as the standard penetration test, cone
penetration test, and other field test procedures.
Chapter 14 first presents the bearing capacity theory and, as an application, the
shallow foundation design procedure is described. Chapter 15 handles deep foundation
design procedures. Various analytical and field pile foundation design procedures
are presented. Negative skin friction, pullout resistance, group piles, and the
consolidation settlement are also discussed.
Finally, in Chapter 16, slope stability problems are presented. The mechanism
of slope failure, analytical methods for calculating the factor of safety, and slope
stabilization principles are discussed.
Preface to the Second Edition xxi
In most of the chapters, many exercise problems were carefully selected for
readers
to practice the use of the learned concepts. Spreadsheet techniques are often
employed in these exercise problems. At the end of each chapter, many problems
are selected, and they can be utilized by students to further exercise their skills in
problem solving, or they can be presented as homework assignments by instructors.
Numerical values of solutions for the problem sections are shown at the end of the
book for the convenience of self-study readers.
Throughout the book, key words are highlighted with bold letters and they also
appear in the subject index at the end of the book; thus, readers can easily search
the locations of these key words in the main section of the book. Some sentences
are highlighted with bold and italic letters, emphasizing the importance of the
concepts. References appear in bold and italic letters in the text and are listed at the
end of each chapter and in the author index at the end of the book.
This book basically uses SI units except the ones cited from original references.
For the measured weight unit, the gf (gram force) unit is used since it is commonly
the observed number on weighing balance. Thus, the value in gf units
should be multiplied by 0.00981 to obtain Newton force if needed. The key unit
conventions are also summarized and a unit conversion table appears on the back of
the front cover page.
Throughout the first as well as the second edition preparation processes, we have
received varying input, constructive review comments, and assistance from many
colleagues and friends from all over the world. We really appreciate the individuals
who supported and guided us. The following is a partial list of these individuals (in
alphabetical order of family names without titles): M. Sherif Aggour (United States),
Fauziah Ahmad (Malaysia), G. L. Sivakumar Babu (India), A. Boominathan (India),
Bodhinanda Chandra (India), Hiroshan Hettiarachchi (United States), Tatsuhisa
Hida (Japan), Yoshiaki Kikuchi (Japan), Taizo Kobayashi (Japan), Kunchithapatha
Madhavan (United States), Mohamed Mekkawy (United States), Achmad Muhiddin
(Indonesia), Mete Omer (United States), Kiyoshi Omine (Japan), Chuzo Tsuchiya
(Japan), Yoichi Watabe (Japan), Noriyuki Yasufuku (Japan), Yoshiaki Yoshimi
(Japan), and Askar Zhussupbekov (Kazakhstan).