Fundamentals of Soil Mechanics for Sedimentary and Residual Soils

by Wesley, Laurence D.

• ISBN13: 9780470376263
• ISBN10: 0470376260
• Edition: 1st
• Format: Hardcover
• Copyright: 2009-08-24
• Publisher: Wiley

Summary

Introducing the first integrated coverage of sedimentary and residual soil engineeringDespite its prevalence in under-developed parts of the United States and most tropical and sub-tropical countries, residual soil is often characterized as a mere extension of conventional soil mechanics in many textbooks. Now, with the rapid growth of construction in these regions, it is essential to gain a fuller understanding of residual soils and their properties-one that's based on an integrated approach to the study of residual and sedimentary soils. One text puts this understanding well within reach: Fundamentals of Soil Mechanics for Sedimentary and Residual Soils.The first resource to provide equal treatment of both residual and sedimentary soils and their unique engineering properties, this skill-building guide offers:A concise introduction to basic soil mechanics, stress-strain behavior, testing, and designIn-depth coverage that spans the full scope of soil engineering, from bearing capacity and foundation design to the stability of slopesA focus on concepts and principles rather than methods, helping you avoid idealized versions of soil behavior and maintain a design approach that is consistent with real soils of the natural worldAn abundance of worked problems throughout, demonstrating in some cases that conventional design techniques applicable to sedimentary soils are not valid for residual soilsNumerous end-of-chapter exercises supported by an online solutions manualFull chapter-ending referencesTaken together, Fundamentals of Soil Mechanics for Sedimentary and Residual Soils is a comprehensive, balanced soil engineering sourcebook that will prove indispensable for practitioners and students in civil engineering, geotechnical engineering, structural engineering, and geology.

Author Biography

Laurence D. Wesley has worked as a practicing geotechnical engineer for over thirty years, and his professional experience encompasses projects in New Zealand, Australia, Indonesia, Malaysia, and Bahrain. A member of American Society of Civil Engineers, he is a recently retired senior lecturer in geotechnical engineering at the University of Auckland.

Table of Contents

Preface	p. xv
Acknowledgments	p. xix
Soil Formation, Composition, and Basic Concepts	p. 1
Weathering Processes, Sedimentary and Residual Soils	p. 1
Clay Minerals	p. 3
Influence of Topography on Weathering Processes	p. 5
Factors Governing the Properties of Sedimentary and Residual Soils	p. 6
Remolded, or Destructured, Soils	p. 10
References	p. 11
Basic Definitions and Phase Relationships	p. 13
Components of Soil	p. 13
Phase Relationships	p. 14
Examples in Use of Phase Relationships	p. 17
Measurement of Basic Properties	p. 22
Bulk Density	p. 22
Water Content	p. 22
Solid Density and Specific Gravity	p. 22
Exercises	p. 24
Basic Index Tests, Soil Classification and Description	p. 27
General	p. 27
Gravel and Sand	p. 27
Clay	p. 28
Silt	p. 28
Particle Size and Its Role in Influencing Properties	p. 28
Measurement of Particle Size	p. 29
Plasticity and Atterberg Limits	p. 31
Determination of Atterberg Limits	p. 31
Liquidity Index of Clay and Relative Density of Sand	p. 35
Sensitivity, Thixotropy, and Activity of Clays	p. 36
Systematic Classification Systems	p. 37
Unified Soil Classification System	p. 38
Additional Notes Regarding Classification	p. 40
Description of In situ (Undisturbed) Characteristics of Soil	p. 42
Classification of Residual Soils	p. 44
Parent Rock	p. 45
Usefulness of Existing Systems	p. 45
Classification of Weathering Profile	p. 46
Importance of Mineralogy and Structure	p. 47
References	p. 48
Stress and Pore Pressure State in the Ground	p. 49
Vertical Stress in the Ground	p. 49
Pore Pressures above Water Table and Seasonal Variations	p. 50
Case A: Coarse-Grained Soils	p. 52
Case B: Low-Permeability Clays	p. 53
Case C: Medium-to High-Permeability Clays	p. 53
Hill Slopes, Seepage, and Pore Pressures	p. 55
Significance of the Water Table (or Phreatic Surface)	p. 56
Horizontal Stress in Ground	p. 57
Worked Examples	p. 60
Worked Example 1	p. 60
Worked Example 2	p. 62
References	p. 64
Exercises	p. 64
Stresses in the Ground from Applied Loads	p. 67
General	p. 67
Elastic Theory Solutions for Stresses Beneath Loaded Areas	p. 68
References	p. 74
Exercises	p. 75
Principle of Effective Stress	p. 77
The Basic Principle	p. 77
Applied Stresses, Drained and Undrained Behavior	p. 80
Pore Pressure Changes Under Undrained Conditions	p. 81
Some Practical Implications of the Principle of Effective Stress	p. 83
Stress State on Soil Element Below Submerged Surface (Bed of Lake or Seabed)	p. 83
Force Resisting Sliding of Concrete Gravity Dam	p. 84
Influence of Rainfall on Slope Stability	p. 85
Ground Settlement Caused By Lowering Water Table	p. 86
References	p. 87
Permeability and Seepage	p. 89
General	p. 89
Pressure, "Head," and Total Head	p. 90
Darcy's Law	p. 92
Notes on Darcy's Law	p. 92
Note on Seepage Velocity	p. 92
Measurement of Permeability	p. 93
General Expression for Seepage in a Soil Mass	p. 95
Steady-State Flow, Laplace Equation, and Flow Nets	p. 97
Flow nets-Conventions Used in Their Construction	p. 99
Boundary Conditions for Flow Nets	p. 100
Methods for Solution of Flow Nets	p. 101
Basic Requirements of Flow Net and Rules for Hand Sketching Flow Nets	p. 102
Use of Flow Nets for Practical Purposes	p. 103
Critical Hydraulic Gradient (and "Quicksand")	p. 104
Quicksand	p. 106
Worked Example	p. 106
Unconfined Flow Nets and Approximations in Conventional Formulation	p. 108
Use of Filters in Designed Structures	p. 109
Vertical Flow Through Single Layers and Multilayers	p. 111
Note on Groundwater Studies and Groundwater Mechanics	p. 113
Flow into Excavations, Drains, and Wells	p. 115
References	p. 117
Exercises	p. 117
Compressibility, Consolidation, and Settlement	p. 121
General Concepts	p. 121
Estimation of Settlement Using Elasticity Theory	p. 122
Drained and Undrained Behavior	p. 123
Limitations of Elasticity Theory	p. 124
Estimation of Settlement Assuming 1-D Behavior	p. 124
Immediate ("Elastic") Settlement and Long-Term (Consolidation) Settlement	p. 126
Immediate and Consolidation Settlement in Sands	p. 126
Immediate and Consolidation Settlement in Clays	p. 126
Consolidation Behavior of Clays (and Silts)	p. 129
Odometer Test	p. 129
Consolidation Characteristics-Magnitude	p. 130
Consolidation Behavior-Time Rate	p. 142
Estimation of Settlement from Odometer Test Results	p. 154
Settlement of a Building Foundation	p. 154
Settlement of Fill on Soft Clay	p. 160
Approximations and Uncertainties in Settlement Estimates Based on Odometer Tests	p. 165
Interpretation of Void Ratio-Stress Curves and Sample Disturbance	p. 165
Assumptions Regarding Pore Pressure State	p. 167
Lateral Deformation	p. 168
Submergence of Fill Loads	p. 168
Use of Terzaghi Theory of Consolidation for Nonlinear Soils	p. 168
Influence of Inadequate Data on Actual Soil Conditions	p. 169
Allowable Settlement	p. 170
Total (or Absolute) Settlement	p. 170
Relative Movement between Structure and Surrounding Ground	p. 170
Differential Settlement of Buildings	p. 170
Radial Flow and Sand (or "Wick") Drains	p. 172
Theory for Design of Sand and Wick Drains	p. 173
Settlement of Foundations on Sand	p. 174
Schmertman Method Using Static Cone Penetrometer Results	p. 175
Burland and Burbidge Method	p. 176
Worked Example	p. 178
References	p. 181
Exercises	p. 182
Shear Strength of Soils	p. 185
Basic Concepts and Principles	p. 185
General Expression for Shear Strength	p. 186
Undrained Shear Strength (Su)	p. 187
Relationship between Strength in Terms of Effective Stress and Undrained Strength	p. 190
Measurement of Shear Strength	p. 190
Direct Shear Test (or Shear Box Test)	p. 190
Triaxial Test	p. 191
Mohr's Circle of Stress	p. 193
Use of Mohr's Circle for Plotting Triaxial Test Results	p. 195
Soil Behavior in Consolidated Undrained and Drained Tests	p. 197
Area Correction in Triaxial Tests	p. 199
Failure Criteria in Terms of Principal Stresses	p. 200
Determination of Angle of Failure Plane	p. 201
Worked Example	p. 201
Practical Use of Undrained Strength and Effective Strength Parameters	p. 203
Shear Strength and Deformation Behavior of Sand	p. 204
Residual Strength of Clays	p. 206
Measurement of Residual Strength	p. 208
Stress Path Concept	p. 209
Pore Pressure Parameters A and B	p. 211
Shear Strength and Deformation Behavior of Clay	p. 212
Behavior of Fully Remolded Clay	p. 212
Behavior of Undisturbed Sedimentary Clays	p. 214
Behavior of Residual Soils	p. 221
Failure Criterion and Determination of c' and ¿' from Consolidated Undrained Tests	p. 224
Typical Values of Effective Strength Parameters for Clays and Silts and Correlations with Other Properties	p. 225
Undrained Strength of Undisturbed and Remolded Soils	p. 228
Sedimentary Clays	p. 228
Remolded Soils	p. 230
Residual Soils	p. 231
Measurement of Undrained Shear Strength	p. 232
Unconfined Compression test	p. 232
Vane Test	p. 232
References	p. 232
Exercises	p. 233
Site Investigations, Field Testing, and Parameter Correlations	p. 235
Overview	p. 235
Drilling	p. 235
Hand Auguring	p. 236
Machine Drilling	p. 236
Continuous Coring with Single-Tube Core Barrel (Also Known as Open Barrel)	p. 238
Rotary Drilling Using Core Barrels	p. 238
Wash Drilling	p. 239
Percussion Boring	p. 239
Undisturbed Sampling Using Sample Tubes	p. 239
Block Sampling	p. 241
Investigation Pits (or Test Pits)	p. 242
In Situ Testing	p. 242
Limitations of Drilling and Undisturbed Sampling	p. 242
Standard Penetration Test (Dynamic Test)	p. 243
Dutch Static Cone Penetration Test CPT	p. 246
Shear Vane Test	p. 249
Correlations between In Situ Test Results and Soil Properties	p. 250
SPT N Values and CPT Values	p. 250
Undrained Shear Strength of Clay	p. 251
Relative Density of Sand	p. 252
Stiffness Modules of Sand	p. 253
References	p. 254
Stability Concepts and Failure Mechanisms	p. 257
Basic Concepts	p. 257
Stability of Slopes	p. 259
Bearing Capacity	p. 261
Retaining Walls	p. 262
Further Observations	p. 264
Safety Factors, Load Factors, and Strength Reduction Factors	p. 264
Questions of Deformation Versus Stability	p. 264
References	p. 265
Bearing Capacity and Foundation Design	p. 267
Bearing Capacity	p. 267
Bearing Capacity in Terms of Effective Stress	p. 270
Bearing Capacity in Terms of Total Stress (Undrained Behavior)	p. 270
Eccentric and Inclined Loads	p. 270
Shallow Foundations on Clay	p. 272
Use of Undrained Shear Strength	p. 272
Application of Factor of Safety	p. 272
Bearing Capacity Versus Settlement Tolerance in Design of Foundations	p. 273
Worked Examples	p. 274
Shallow Foundations on Sand	p. 276
Use of Bearing Capacity Theory	p. 276
Empirical Methods for Foundations on Sand	p. 277
Pile Foundations	p. 278
Basic Concepts and Pile Types	p. 278
Pile-Bearing Capacity-Basic Formula and Methods of Estimation	p. 281
Bearing Capacity of Piles in Clay	p. 282
Bearing Capacity of Piles in Sand	p. 285
Pile Group Behavior	p. 286
Lateral Load Capacity of Piles	p. 289
References	p. 303
Exercises	p. 304
Earth Pressure and Retaining Walls	p. 307
Coulomb Wedge Analysis	p. 307
At-Rest Pressure, Active Pressure, Passive Pressure, and Associated Deformations	p. 312
Rankine Earth Pressures	p. 312
Influence of Wall Friction	p. 316
Earth Pressure Coefficients	p. 316
Total Stress Analysis	p. 317
Maximum Height of Unsupported Vertical Banks or Cuts	p. 317
Construction Factors Influencing Earth Pressures on Retaining Walls	p. 319
Propped (Strutted) Trenches	p. 321
Retaining-Wall Design Example	p. 322
Sheet Pile (and Similar) Retaining Walls	p. 329
FreeStanding and Propped Cantilever Walls	p. 329
Reinforced-Earth Walls	p. 337
Concept and General Behavior	p. 337
Reinforcement Types	p. 338
Basic Design Procedures	p. 339
Other Matters	p. 349
References	p. 351
Exercises	p. 351
Stability of Slopes	p. 355
Introduction	p. 355
Analysis Using Circular Arc Failure Surfaces	p. 357
Circular Arc Analysis Using Total Stresses	p. 359
Circular Arc Analysis in Terms of Effective Stresses	p. 360
Example Calculation Using Bishop Method	p. 362
Bishop's Method for Submerged Slopes	p. 363
Stability Analysis of Infinite Slopes	p. 366
Short- and Long-Term Stability of Built Slopes	p. 368
Excavated Slopes	p. 369
Embankments on Soft Clays	p. 371
Stability Analysis for Earth Dams	p. 377
Estimation of Pore-Water Pressures During or at End of Construction	p. 377
Full-Reservoir Steady-State Seepage Condition	p. 379
Rapid Drawdown Pore Pressures	p. 380
Influence of Climate and Weather on Stability of Slopes	p. 381
Stability Analysis Using Noncircular Failure Surfaces	p. 385
References	p. 387
Exercises	p. 387
Soil Compaction	p. 391
Earthworks and Soil Compaction	p. 391
Compaction Behavior of Soils	p. 391
Control of Compaction	p. 397
Traditional Method of Compaction Control	p. 397
Alternative Compaction Control Based on Undrained Shear Strength and Air Voids	p. 397
Difficulties in Compacting Clays	p. 401
Soils Considerably Wetter Than Optimum Water Content	p. 401
Soils That Soften During Compaction	p. 401
Compaction of Granular and Non-Plastic Materials	p. 402
References	p. 404
Special Soil Types	p. 405
General Comments	p. 405
Partially Saturated Soils	p. 406
Occurrence	p. 406
Measurements of Degree of Saturation	p. 407
Mechanics of Partially Saturated Soils	p. 408
Expansive or Swelling Clays	p. 415
Basic Concepts of Expansive Behavior	p. 415
Estimation of Swelling Pressure and Swell Magnitude	p. 416
Estimation of Swell Magnitude	p. 420
Collapsing Soils	p. 421
References	p. 424
Index	p. 425
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