Preface to the Third Edition xiii
About the Authors xv
Acknowledgements xvii
Part One: Theory 1
1 Groundwater in Construction 3
1.1 Groundwater in the Hydrologic Cycle 3
1.2 Origins of Dewatering 6
1.3 Development of Modern Dewatering Technology 6
2 The Geology of Soils 10
2.1 Geologic Time Frame 11
2.2 Formation of Soils 11
2.3 Mineral Composition of Soils 11
2.4 Rivers 12
2.5 Lakes 12
2.6 Estuaries 14
2.7 Beaches 14
2.8 Wind Deposits 14
2.9 Glaciersâ"The Pleistocene Epoch 14
2.10 Rock 16
2.11 Limestone and Coral 17
2.12 Tectonic Movements 19
2.13 Man-made Ground 19
3 Soils and Water 22
3.1 Soil Structure 22
3.2 Gradation of Soils 22
3.3 Porosity, Void Ratio, and Water Content 26
3.4 Relative Density, Specific Gravity, and Unit Weight 26
3.5 Capillarity and Unsaturated Flow 27
3.6 Specific Yield and Specific Retention 27
3.7 Hydraulic Conductivity 29
3.8 Plasticity and Cohesion of Silts and Clays 35
3.9 Unified Soil Classification System (ASTM D-2487) 35
3.10 Soil Descriptions 39
3.11 Visual and Manual Classification of Soils 40
3.12 Seepage Forces and Soil Stress 42
3.13 Gravity Drainage of Granular Soils 43
3.14 Drainage of Fine-grained Soils: Pore Pressure Control 44
3.15 Settlement as a Result of Dewatering 46
3.16 Preconsolidation 48
3.17 Other Side Effects of Dewatering 50
4 Hydrology of the Ideal Aquifer 52
4.1 Definition of the Ideal Aquifer 52
4.2 Transmissivity T 53
4.3 Storage Coefficient C s and Specific Yield 53
4.4 Pumping from a Confined Aquifer 55
4.5 Recovery Calculations 56
4.6 The Unconfined or Water Table Aquifer 57
4.7 Specific Capacity 58
5 Characteristics of Natural Aquifers 61
5.1 Anisotropy: Stratified Soils 61
5.2 Horizontal Variability 64
5.3 Recharge Boundaries: Radius of Influence R 0 64
5.4 Barrier Boundaries 65
5.5 Delayed Release from Storage 65
6 Dewatering Design Using Analytical Methods 66
6.1 Radial Flow to a Well in a Confined Aquifer 66
6.2 Radial Flow to a Well in a Water Table Aquifer 68
6.3 Radial Flow to a Well in a Mixed Aquifer 69
6.4 Flow to a Drainage Trench from a Line Source 69
6.5 The System as a Well: Equivalent Radius r s 70
6.6 Radius of Influence R 0 71
6.7 Hydraulic Conductivity K and Transmissivity T 71
6.8 Initial Head H and Final Head h 72
6.9 Partial Penetration 72
6.10 Storage Depletion 73
6.11 Specific Capacity of the Aquifer 75
6.12 Cumulative Drawdown or Superposition 76
6.13 Capacity of the Well Q w 77
6.14 Flow Net Analysis and the Method of Fragments 79
6.15 Concentric Dewatering Systems 80
6.16 Vertical Flow 81
6.17 Gravel Tremie 82
7 Groundwater Modeling Using Numerical Methods 84
7.1 Models in Dewatering Practice 84
7.2 When to Consider a Numerical Model 87
7.3 Principal Steps in Model Design and Application 90
7.4 The Conceptual Model: Defining the Problem to Be Modeled 90
7.5 Selecting the Program 91
7.6 Introduction to MODFLOW 91
7.7 Verification 94
7.8 Calibration 94
7.9 Prediction and Parametric Analyses 95
7.10 Some Practical Modeling Problems 95
7.11 2-D Model: Well System in a Water Table Aquifer 95
7.12 Calibrating the Model 97
7.13 3-D Model: Partial Penetration 98
7.14 3-D Model: Vertical Flow 101
7.15 3-D Model: Transient Analysis of a Progressive Trench Excavation 102
8 Piezometers for Groundwater Measurement and Monitoring 111
8.1 Subsurface Conditions 111
8.2 Ordinary Piezometers and True Piezometers 111
8.3 Piezometer Construction 113
8.4 Verification of Piezometer Performance 115
8.5 Obtaining Data from Piezometers 115
8.6 Pore Pressure Piezometers in Fine-grained Soils 117
8.7 Direct Push Technologies for Piezometer Installation 118
9 Pumping Tests 121
9.1 When a Pumping Test Is Advisable 121
9.2 Planning the Pumping Test 122
9.3 Design of the Pumping Well 122
9.4 Piezometer Array 125
9.5 Duration of Drawdown and Recovery 126
9.6 Pumping Rate 128
9.7 Monitoring the Pumping Test 128
9.8 Analysis of Pumping Test Data 129
9.9 Tidal Corrections 132
9.10 Well Loss 134
9.11 Step Drawdown Tests 136
9.12 Testing of Low-yield Wells 137
9.13 Delayed Storage Release: Boulton Analysis 138
10 Surface Hydrology 141
10.1 Lakes and Reservoirs 141
10.2 Bays and Ocean Beaches 141
10.3 Rivers 141
10.4 Precipitation 144
10.5 Disposal of Dewatering Discharge 145
10.6 Water from Existing Structures 150
11 Geotechnical Investigation for Dewatering 152
11.1 Investigation Approach and Objectives 152
11.2 Preliminary Studies and Investigations 153
11.3 Borings 154
11.4 In Situ Test Methods 164
11.5 Piezometers and Observation Wells 167
11.6 Borehole Seepage Tests for Evaluation of Hydraulic Conductivity 169
11.7 Laboratory Analysis of Samples 178
11.8 Chemical Testing of Groundwater 180
11.9 Geophysical Methods 180
11.10 Pumping Tests 181
11.11 Permanent Effect of Structures on the Groundwater Body 181
11.12 Investigation of the Potential Side Effects of Dewatering 182
11.13 Presentation in the Bidding Documents 183
12 Pump Theory 185
12.1 Types of Pumps Used in Dewatering 185
12.2 Total Dynamic Head 189
12.3 Pump Performance Curves 189
12.4 Vacuum Pumps 190
12.5 Air Lift Pumping 192
12.6 Testing of Pumps 193
13 Groundwater Chemistry, Bacteriology, and Fouling of Dewatering Systems 195
13.1 Types of Corrosion 195
13.2 Corrosive Groundwater Conditions 196
13.3 Dewatering in Corrosive Groundwater Conditions 198
13.4 Incrustation 198
13.5 Mineral Incrustation 199
13.6 Biological Incrustation 200
13.7 Dewatering Systems and Incrustation 205
13.8 Field Evaluation of Well Fouling 208
13.9 Rehabilitation and Maintenance 209
13.10 Analysis of Groundwater 215
14 Contaminated Groundwater 222
14.1 Contaminants Frequently Encountered 222
14.2 Design Options at a Contaminated Site 223
14.3 Estimating Water Quantity to Be Treated 225
14.4 Other Considerations in Treatment Design 225
14.5 Elements of Groundwater Treatment 226
14.6 Recovery of Contaminated Water with Dewatering Techniques 229
14.7 Dynamic Barriers 232
14.8 Wellpoint Systems and Multiphase Contaminants 232
14.9 Reinjection 233
14.10 Health and Safety 234
14.11 Regulating Authorities 234
15 Piping Systems 238
15.1 Dewatering Pipe and Fittings 238
15.2 Losses in Discharge Piping 241
15.3 Losses in Wellpoint Header Lines 241
15.4 Losses in Ejector Headers 243
15.5 Water Hammer 243
Part Two: Practice 245
16 Choosing a Method of Groundwater Control 247
16.1 To Pump or Not to Pump 247
16.2 Open Pumping Versus Predrainage 247
16.3 Methods of Predrainage 250
16.4 Methods of Cutoff and Exclusion 253
16.5 Methods in Combination 253
17 Sumps, Drains, and Open Pumping 259
17.1 Soil and Water Conditions 259
17.2 Boils and Blows 259
17.3 Construction of Sumps 260
17.4 Ditches and Drains 261
17.5 Gravel Bedding 261
17.6 Slope Stabilization with Sandbags, Gravel, and Geotextiles 262
17.7 Use of Geotextiles 262
17.8 Soldier Piles and Lagging: Standup Time 263
17.9 Longterm Effect of Buried Drains 264
17.10 Leaking Utilities 264
17.11 Battered Wellpoints 265
17.12 Horizontal Wellpoints 265
18 Deep Well Systems 267
18.1 Testing During Well Construction 267
18.2 Well Installation and Construction Methods 267
18.3 Wellscreen and Casing 279
18.4 Filter Packs 285
18.5 Development of Wells 291
18.6 Well Construction Details 295
18.7 Pressure Relief Wells, Vacuum Wells 300
18.8 Wells That Pump Sand 300
18.9 Systems of Low-capacity Wells 304
19 Wellpoint Systems 307
19.1 Suction Lifts 307
19.2 Single and Multistage Systems 310
19.3 Wellpoint Design 310
19.4 Wellpoint Spacing 313
19.5 Wellpoint Depth 315
19.6 Installation of Wellpoints 318
19.7 Filter Sands 320
19.8 Wellpoint Pumps, Header, and Discharge Piping 321
19.9 Tuning Wellpoint Systems 323
19.10 Air/Water Separation 326
19.11 Automatic Mops 326
19.12 Vertical Wellpoint Pumps 326
19.13 Wellpoints for Stabilization of Fine-grained Soils 329
19.14 Wellpoint Systems for Trench Work 331
20 Ejector Systems and Other Methods 336
20.1 Two-pipe and Single-pipe Ejectors 336
20.2 Ejector Pumping Stations 338
20.3 Ejector Efficiency 339
20.4 Design of Nozzles and Venturis 340
20.5 Ejector Risers and Swings 344
20.6 Ejector Headers 344
20.7 Ejector Installation 345
20.8 Ejectors and Groundwater Quality 345
20.9 Ejectors and Soil Stabilization 349
20.10 Drilled Horizontal Wells 349
20.11 Trencher Drains 355
21 Groundwater Cutoff Structures 358
21.1 Cutoff Terminology and Efficiency 358
21.2 Steel Sheet Piling 358
21.3 Slurry Trenches 367
21.4 Slurry Diaphragm Walls 379
21.5 Secant Piles 390
21.6 Deep Soil Mixing 398
21.7 Tremie Seals 405
22 Grouting Methods 410
22.1 Permeation Grouting 410
22.2 Jet Grouting 439
22.3 Rock Curtain Grouting 456
22.4 Grouting of Structures and Flowpaths 474
23 Dewatering and Groundwater Control for Soft Ground Tunneling 491
23.1 Soft Ground Tunneling Methods with Conventional Dewatering 491
23.2 Ground Behavior 495
23.3 Mixed-face Ground Conditions 497
23.4 Dewatering Design for Tunnels 497
23.5 Methods of Tunnel Predrainage 499
23.6 Tunneling Techniques with Built-in Groundwater Control 500
23.7 Compressed Air Tunneling 504
23.8 Dewatering of Access Shafts, Penetrations, and Starter Tunnels 505
24 Ground Freezing 508
24.1 General Principles 508
24.2 Freezing Applications 509
24.3 Freezing Methods and Equipment 515
24.4 Ground Freezing and Soils 528
24.5 Design 533
24.6 Effect of Groundwater Movement 534
24.7 Ground Movement Potential as a Result of Artificial Freezing 534
25 Artificial Recharge 539
25.1 Recharge Applications 539
25.2 Design Objectives 540
25.3 Potential Problems with Recharge Water and Plugging of Wells 541
25.4 Sources of Recharge Water 543
25.5 Treatment of Recharge Water 544
25.6 Construction of Recharge Systems 545
25.7 Operation and Maintenance of Recharge Systems 550
25.8 Permits for Recharge Operations 550
26 Electrical Design for Dewatering Systems 556
26.1 Electrical Motors 556
26.2 Motor Controls 561
26.3 Power Factor 564
26.4 Electric Generators 564
26.5 Switchgear and Distribution Systems 566
26.6 Grounding of Electrical Circuits 570
26.7 Cost of Electrical Energy 570
27 Long-term Dewatering Systems 572
27.1 Types of Long-term Systems 572
27.2 Access for Maintenance 572
27.3 Instrumentation and Controls 575
28 Dewatering Costs 577
28.1 Format of the Estimate 577
28.2 Basic Cost Data 577
28.3 Mobilization 578
28.4 Installation and Removal 578
28.5 Operation and Maintenance 579
28.6 Summary 581
28.7 Specialty Dewatering Subcontractor Quotations 581
29 Dewatering Specifications, Allocation of Risk, Dispute Avoidance, and Resolution of Disputes 584
29.1 Performance Specifications 585
29.2 Owner-designed Dewatering Systems 586
29.3 Specified Minimum Systems 586
29.4 Dewatering Submittals 586
29.5 Third-party Damage Caused by Dewatering 587
29.6 Differing Site Conditions 588
29.7 Disputes Review Board 595
Appendix A 597
Appendix B 603
Appendix c 620
Index 623
