Fundamentals of Geotechnical Engineering

Front Cover......Page 1
Title Page......Page 4
Copyright......Page 5
Contents......Page 10
1.1 Geotechnical Engineering Prior to the 18[sup(th)] Century......Page 16
1.2 Preclassical Period of Soil Mechanics (1700 –1776)......Page 19
1.4 Classical Soil Mechanics—Phase II (1856 –1910)......Page 20
1.5 Modern Soil Mechanics (1910 –1927)......Page 21
1.6 Geotechnical Engineering after 1927 7 References......Page 22
References......Page 26
2.1 Natural Soil Deposits-General......Page 28
2.4 Alluvial Deposits......Page 29
Meander Belt Deposits......Page 30
2.5 Lacustrine Deposits......Page 31
2.7 Aeolian Soil Deposits......Page 32
2.8 Organic Soil......Page 33
2.9 Soil-Particle Size......Page 34
2.10 Clay Minerals......Page 35
2.11 Specific Gravity (G[sub(s)]......Page 38
Sieve Analysis......Page 39
Hydrometer Analysis......Page 42
2.13 Effective Size, Uniformity Coefficient, and Coefficient of Gradation......Page 47
Problems......Page 50
References......Page 52
3.1 Weight–Volume Relationships......Page 53
Volume Relationships......Page 54
Weight Relationships......Page 55
3.2 Relationships among Unit Weight, Void Ratio, Moisture Content, and Specific Gravity......Page 56
3.3 Relationships among Unit Weight, Porosity, and Moisture Content......Page 59
3.4 Relative Density......Page 66
3.5 Consistency of Soil......Page 68
Liquid Limit (LL)......Page 69
Plastic Limit (PL)......Page 72
Shrinkage Limit (SL)......Page 73
3.6 Activity......Page 75
3.8 Plasticity Chart......Page 77
AASHTO Classification System......Page 78
Unified Soil Classification System......Page 82
Problems......Page 90
References......Page 92
4.1 Compaction—General Principles......Page 93
4.2 Standard Proctor Test......Page 94
Effect of Compaction Effort......Page 98
4.4 Modified Proctor Test......Page 101
4.5 Empirical Relationships......Page 105
4.6 Field Compaction......Page 106
4.7 Specifications for Field Compaction......Page 109
Sand Cone Method (ASTM Designation D-1556)......Page 111
Rubber Balloon Method (ASTM Designation D-2167)......Page 113
Vibroflotation......Page 114
Blasting......Page 118
4.10 Effect of Compaction on Cohesive Soil Properties......Page 119
Problems......Page 122
References......Page 124
5.1 Bernoulli’s Equation......Page 126
5.2 Darcy’s Law......Page 128
5.3 Hydraulic Conductivity......Page 130
Constant Head Test......Page 131
Falling Head Test......Page 132
Granular Soil......Page 137
Cohesive Soil......Page 140
5.6 Equivalent Hydraulic Conductivity in Stratified Soil......Page 144
5.7 Permeability Test in the Field by Pumping from Wells......Page 146
5.8 Laplace’s Equation of Continuity......Page 149
5.9 Flow Nets......Page 151
Seepage Calculation from a Flow Net......Page 153
Problems......Page 157
References......Page 161
6.1 Stresses in Saturated Soil without Seepage......Page 162
Upward Seepage......Page 166
Downward Seepage......Page 168
6.3 Effective Stress in Partially Saturated Soil......Page 171
6.4 Seepage Force......Page 172
6.5 Heaving in Soil Due to Flow Around Sheet Piles......Page 174
6.6 Stress Caused by a Point Load......Page 176
6.7 Westergaard’s Solution for Vertical Stress Due to a Point Load......Page 178
6.8 Vertical Stress Caused by a Line Load......Page 180
6.9 Vertical Stress Caused by a Line Load of Finite Length......Page 181
6.10 Vertical Stress Caused by a Strip Load (Finite Width and Infinite Length)......Page 185
6.11 Vertical Stress Below a Uniformly Loaded Circular Area......Page 187
6.12 Vertical Stress Caused by a Rectangularly Loaded Area......Page 189
Vertical Stress Due to a Rectangularly Loaded Area......Page 194
Problems......Page 195
References......Page 200
7.1 Fundamentals of Consolidation......Page 201
7.2 One-Dimensional Laboratory Consolidation Test......Page 203
7.3 Void Ratio–Pressure Plots......Page 205
7.4 Normally Consolidated and Overconsolidated Clays......Page 207
7.5 Effect of Disturbance on Void Ratio–Pressure Relationship......Page 209
7.6 Calculation of Settlement from One-Dimensional Primary Consolidation......Page 211
7.7 Compression Index (C[sub(c)] and Swell Index (C[sub(s)]......Page 213
7.8 Settlement from Secondary Consolidation......Page 218
7.9 Time Rate of Consolidation......Page 221
Logarithm-of-Time Method......Page 228
Square-Root-of-Time Method......Page 229
7.11 Calculation of Primary Consolidation Settlement under a Foundation......Page 235
7.12 Skempton-Bjerrum Modification for Consolidation Settlement......Page 238
7.13 Precompression—General Considerations......Page 242
Derivation of Equations to Obtain (f) and t[Sub(2)]......Page 243
Procedure for Obtaining Precompression Parameters......Page 244
7.14 Sand Drains......Page 246
Average Degree of Consolidation Due to Radial Drainage Only......Page 247
Average Degree of Consolidation Due to Vertical and Radial Drainage......Page 250
Problems......Page 252
References......Page 256
8.1 Mohr-Coulomb Failure Criteria......Page 258
8.2 Inclination of the Plane of Failure Caused by Shear......Page 260
8.3 Direct Shear Test......Page 262
Drained Direct Shear Test on Saturated Sand and Clay......Page 266
General Comments on Direct Shear Test......Page 267
8.4 Triaxial Shear Test......Page 270
8.5 Consolidated-Drained Test......Page 271
Effective Stress Friction Angle of Cohesive Soils......Page 275
8.6 Consolidated-Undrained Test......Page 280
8.7 Unconsolidated-Undrained Test......Page 285
8.8 Unconfined Compression Test on Saturated Clay......Page 287
8.9 Sensitivity and Thixotropy of Clay......Page 289
8.10 Anisotropy in Undrained Shear Strength......Page 291
Problems......Page 293
References......Page 295
9 Slope Stability......Page 297
9.1 Factor of Safety......Page 298
9.2 Stability of Infinite Slopes......Page 299
Analysis of Finite Slope with Plane Failure Surface (Culmann’s Method)......Page 302
9.4 Analysis of Finite Slope with Circularly Cylindrical Failure Surface—General......Page 305
Slopes in Homogeneous Clay Soil with    0 (Undrained Condition)......Page 307
Slopes in Clay Soil with    0; and c[sub(u)] Increasing with Depth......Page 313
Slopes in Homogeneous Soil with      0......Page 315
9.6 Method of Slices......Page 325
9.7 Bishop’s Simplified Method of Slices......Page 329
Michalowski’s Solution......Page 333
Saturated Clay (   0 Condition)......Page 337
c –   Soil (Zero Pore Water Pressure)......Page 339
Problems......Page 341
References......Page 344
Collection of Preliminary Information......Page 345
Site Investigation......Page 346
10.2 Exploratory Borings in the Field......Page 348
10.3 Procedures for Sampling Soil......Page 352
Split-Spoon Sampling......Page 353
10.4 Observation of Water Levels......Page 358
10.5 Vane Shear Test......Page 360
10.6 Cone Penetration Test......Page 366
Correlation between Relative Density (D[sub(r)]) and q[sub(c)] for Sand......Page 368
Correlation between q[sub(c)] and N[sub(60)]......Page 371
Correlations for Undrained Shear Strength (c[sub(u)]), Preconsolidation Pressure (   c), and Overconsolidation Ratio (OCR) for Clays......Page 372
10.7 Pressuremeter Test (PMT)......Page 373
10.8 Dilatometer Test......Page 375
10.9 Coring of Rocks......Page 378
10.10 Preparation of Boring Logs......Page 380
Problems......Page 382
References......Page 386
11.1 Earth Pressure at Rest......Page 388
Earth Pressure at Rest for Partially Submerged Soil......Page 390
Rankine’s Active State......Page 392
Rankine’s Passive State......Page 396
Effect of Wall Yielding......Page 399
Backfill—Partially Submerged Cohesionless Soil Supporting Surcharge Active Case......Page 401
Backfill—Cohesive Soil with Horizontal Backfill Active Case......Page 404
Passive Case......Page 407
11.4 Rankine’s Active and Passive Pressure with Sloping Backfill......Page 415
11.5 Retaining Walls with Friction......Page 420
Active Case......Page 422
Passive Case......Page 428
11.7 Passive Pressure Assuming Curved Failure Surface in Soil......Page 430
Problems......Page 433
References......Page 435
12 Shallow Foundations—Bearing Capacity and Settlement......Page 437
12.1 General Concepts......Page 438
12.2 Ultimate Bearing Capacity Theory......Page 440
Modification to Terzaghi’s Bearing Capacity Equation......Page 443
Net Ultimate Bearing Capacity......Page 444
12.3 Modification of Bearing Capacity Equations for Water Table......Page 445
12.4 The Factor of Safety......Page 446
12.5 Eccentrically Loaded Foundations......Page 451
Foundations with Two-Way Eccentricity......Page 453
12.6 Types of Foundation Settlement......Page 462
12.7 Elastic Settlement......Page 463
12.8 Range of Material Parameters for Computing Elastic Settlement......Page 472
12.9 Settlement of Sandy Soil: Use of Strain Influence Factor......Page 473
A Case History of the Calculation of Se Using the Strain Influence Factor......Page 475
12.10 Allowable Bearing Pressure in Sand Based on Settlement Consideration......Page 477
12.11 Common Types of Mat Foundations......Page 478
12.12 Bearing Capacity of Mat Foundations......Page 479
12.13 Compensated Foundations......Page 482
Problems......Page 484
References......Page 488
13.1 Retaining Walls—General......Page 490
13.2 Proportioning Retaining Walls......Page 492
13.3 Application of Lateral Earth Pressure Theories to Design......Page 493
13.4 Check for Overturning......Page 495
13.5 Check for Sliding along the Base......Page 497
13.6 Check for Bearing Capacity Failure......Page 499
Metal Strips......Page 508
Nonbiodegradable Fabrics......Page 509
Geogrids......Page 510
13.10 Retaining Walls with Metallic Strip Reinforcement......Page 511
Calculation of Active Horizontal Pressure......Page 512
Factor of Safety against Tie Failure......Page 513
General......Page 514
External Stability......Page 515
Internal Stability......Page 520
External Stability......Page 521
13.13 Retaining Walls with Geogrid Reinforcement......Page 523
13.14 Braced Cuts—General......Page 525
13.15 Lateral Earth Pressure in Braced Cuts......Page 529
Limitations for the Pressure Envelopes......Page 530
13.16 Soil Parameters for Cuts in Layered Soil......Page 531
Struts......Page 532
Wales......Page 534
13.18 Heave of the Bottom of a Cut in Clay......Page 538
13.19 Lateral Yielding of Sheet Piles and Ground Settlement......Page 541
Problems......Page 542
References......Page 546
14.1 Need for Pile Foundations......Page 547
Steel Piles......Page 549
Concrete Piles......Page 552
Timber Piles......Page 555
Point Bearing Piles......Page 557
14.4 Installation of Piles......Page 558
14.5 Load Transfer Mechanism......Page 560
14.6 Equations for Estimation of Pile Capacity......Page 561
Load-Carrying Capacity of the Pile Point, Q[sub(p)]......Page 562
14.7 Calculation of q[sub(p)]—Meyerhof’s Method......Page 563
Frictional Resistance in Sand......Page 565
Frictional (or Skin) Resistance in Clay......Page 568
Correlation with Cone Penetration Test Results......Page 570
14.9 Allowable Pile Capacity......Page 571
14.10 Load-Carrying Capacity of Pile Point Resting on Rock......Page 572
Determination of S[sub(e(2))]......Page 578
Determination of S[sub(e(3))]......Page 579
14.12 Pile-Driving Formulas......Page 581
14.13 Negative Skin Friction......Page 584
Clay Fill over Granular Soil (Figure 14.20a)......Page 585
Granular Soil Fill over Clay (Figure 14.20b)......Page 586
14.14 Group Piles—Efficiency......Page 589
Piles in Sand......Page 590
Piles in Clay......Page 591
Piles in Rock......Page 592
General Comments......Page 593
14.15 Elastic Settlement of Group Piles......Page 594
14.16 Consolidation Settlement of Group Piles......Page 595
14.17 Types of Drilled Shafts......Page 599
Dry Method of Construction......Page 600
Casing Method of Construction......Page 601
Wet Method of Construction......Page 603
14.19 Estimation of Load-Bearing Capacity......Page 604
Drilled Shafts in Sand......Page 605
Drilled Shafts in Clay......Page 606
14.21 Load-Bearing Capacity Based on Settlement......Page 610
Cohesive Soil......Page 611
Cohesionless Soil......Page 613
Problems......Page 618
References......Page 624
Answers to Selected Problems......Page 626
Index......Page 630