Construction Dewatering and Groundwater Control: New Methods and Applications Book

Preface to the Third Edition     xiii
About the Authors     xv
Acknowledgements     xvii
Theory     1
Groundwater in Construction     3
Groundwater in the Hydrologic Cycle     3
Origins of Dewatering     6
Development of Modern Dewatering Technology     6
The Geology of Soils     10
Geologic Time Frame     11
Formation of Soils     11
Mineral Composition of Soils     11
Rivers     12
Lakes     12
Estuaries     14
Beaches     14
Wind Deposits     14
Glaciers-The Pleistocene Epoch     14
Rock     16
Limestone and Coral     17
Tectonic Movements     19
Man-made Ground     19
Soils and Water     22
Soil Structure     22
Gradation of Soils     22
Porosity, Void Ratio, and Water Content     26
Relative Density, Specific Gravity, and Unit Weight     26
Capillarity and Unsaturated Flow     27
Specific Yield and Specific Retention     27
Hydraulic Conductivity     29
Plasticity and Cohesion of Silts and Clays     35
Unified Soil Classification System (ASTM D-2487)     35
Soil Descriptions     39
Visual and Manual Classification of Soils     40
Seepage Forces and Soil Stress     42
Gravity Drainage of Granular Soils     43
Drainage of Fine-grained Soils: Pore Pressure Control     44
Settlement as a Result of Dewatering     46
Preconsolidation     48
Other Side Effects of Dewatering     50
Hydrology of the Ideal Aquifer     52
Definition of the Ideal Aquifer     52
Transmissivity T     53
Storage Coefficient C[subscript s] and Specific Yield     53
Pumping from a Confined Aquifer     55
Recovery Calculations     56
The Unconfined or Water Table Aquiter     57
Specific Capacity     58
Characteristics of Natural Aquifers     61
Anisotropy: Stratified Soils     61
Horizontal Variability     64
Recharge Boundaries: Radius of Influence R[subscript 0]     64
Barrier Boundaries     65
Delayed Release from Storage     65
Dewatering Design Using Analytical Methods     66
Radial Flow to a Well in a Confined Aquifer     66
Radial Flow to a Well in a Water Table Aquifer     68
Radial Flow to a Well in a Mixed Aquifer     69
Flow to a Drainage Trench from a Line Source     69
The System as a Well: Equivalent Radius r[subscript s]     70
Radius of Influence R[subscript 0]     71
Hydraulic Conductivity K and Transmissivity T     71
Initial Head H and Final Head h     72
Partial Penetration     72
Storage Depletion     73
Specific Capacity of the Aquifer     75
Cumulative Drawdown or Superposition     76
Capacity of the Well Q[subscript w]     77
Flow Net Analysis and the Method of Fragments     79
Concentric Dewatering Systems     80
Vertical Flow     81
Gravel Tremie     82
Groundwater Modeling Using Numerical Methods     84
Models in Dewatering Practice     84
When to Consider a Numerical Model     87
Principal Steps in Model Design and Application     90
The Conceptual Model: Defining the Problem to Be Modeled     90
Selecting the Program     91
Introduction to MODFLOW     91
Verification      94
Calibration     94
Prediction and Parametric Analyses     95
Some Practical Modeling Problems     95
2-D Model: Well System in a Water Table Aquifer     95
Calibrating the Model     97
3-D Model: Partial Penetration     98
3-D Model: Vertical Flow     101
3-D Model: Transient Analysis of a Progressive Trench Excavation     102
Piezometers for Groundwater Measurement and Monitoring     111
Subsurface Conditions     111
Ordinary Piezometers and True Piezometers     111
Piezometer Construction     113
Verification of Piezometer Performance     115
Obtaining Data from Piezometers     115
Pore Pressure Piezometers in Fine-grained Soils     117
Direct Push Technologies for Piezometer Installation     118
Pumping Tests     121
When a Pumping Test Is Advisable     121
Planning the Pumping Test     122
Design of the Pumping Well     122
Piezometer Array     125
Duration of Drawdown and Recovery     126
Pumping Rate     128
Monitoring the Pumping Test     128
Analysis of Pumping Test Data     129
Tidal Corrections     132
Well Loss     134
Step Drawdown Tests     136
Testing of Low-yield Wells     137
Delayed Storage Release: Boulton Analysis     138
Surface Hydrology     141
Lakes and Reservoirs     141
Bays and Ocean Beaches     141
Rivers     141
Precipitation     144
Disposal of Dewatering Discharge     145
Water from Existing Structures     150
Geotechnical Investigation for Dewatering     152
Investigation Approach and Objectives     152
Preliminary Studies and Investigations     153
Borings     154
In Situ Test Methods     164
Piezometers and Observation Wells     167
Borehole Seepage Tests for Evaluation of Hydraulic Conductivity     169
Laboratory Analysis of Samples     178
Chemical Testing of Groundwater     180
Geophysical Methods     180
Pumping Tests     181
Permanent Effect of Structures on the Groundwater Body     181
Investigation of the Potential Side Effects of Dewatering     182
Presentation in the Bidding Documents     183
Pump Theory      185
Types of Pumps Used in Dewatering     185
Total Dynamic Head     189
Pump Performance Curves     189
Vacuum Pumps     190
Air Lift Pumping     192
Testing of Pumps     193
Groundwater Chemistry, Bacteriology, and Fouling of Dewatering Systems     195
Types of Corrosion     195
Corrosive Groundwater Conditions     196
Dewatering in Corrosive Groundwater Conditions     198
Incrustation     198
Mineral Incrustation     199
Biological Incrustation     200
Dewatering Systems and Incrustation     205
Field Evaluation of Well Fouling     208
Rehabilitation and Maintenance     209
Analysis of Groundwater     215
Contaminated Groundwater     222
Contaminants Frequently Encountered     222
Design Options at a Contaminated Site     223
Estimating Water Quantity to Be Treated     225
Other Considerations in Treatment Design     225
Elements of Groundwater Treatment     226
Recovery of Contaminated Water with Dewatering Techniques     229
Dynamic Barriers     232
Wellpoint Systems and Multiphase Contaminants     232
Reinjection     233
Health and Safety     234
Regulating Authorities     234
Piping Systems     238
Dewatering Pipe and Fittings     238
Losses in Discharge Piping     241
Losses in Wellpoint Header Lines     241
Losses in Ejector Headers     243
Water Hammer     243
Practice     245
Choosing a Method of Groundwater Control     247
To Pump or Not to Pump     247
Open Pumping Versus Predrainage     247
Methods of Predrainage     250
Methods of Cutoff and Exclusion     253
Methods in Combination     253
Sumps, Drains, and Open Pumping     259
Soil and Water Conditions     259
Boils and Blows     259
Construction of Sumps     260
Ditches and Drains     261
Gravel Bedding     261
Slope Stabilization with Sandbags, Gravel, and Geotextiles     262
Use of Geotextiles     262
Soldier Piles and Lagging: Standup Time     263
Longterm Effect of Buried Drains     264
Leaking Utilities     264
Battered Wellpoints      265
Horizontal Wellpoints     265
Deep Well Systems     267
Testing During Well Construction     267
Well Installation and Construction Methods     267
Wellscreen and Casing     279
Filter Packs     285
Development of Wells     291
Well Construction Details     295
Pressure Relief Wells, Vacuum Wells     300
Wells That Pump Sand     300
Systems of Low-capacity Wells     304
Wellpoint Systems     307
Suction Lifts     307
Single and Multistage Systems     310
Wellpoint Design     310
Wellpoint Spacing     313
Wellpoint Depth     315
Installation of Wellpoints     318
Filter Sands     320
Wellpoint Pumps, Header, and Discharge Piping     321
Tuning Wellpoint Systems     323
Air/Water Separation     326
Automatic Mops     326
Vertical Wellpoint Pumps     326
Wellpoints for Stabilization of Fine-grained Soils     329
Wellpoint Systems for Trench Work     331
Ejector Systems and Other Methods     336
Two-pipe and Single-pipe Ejectors     336
Ejector Pumping Stations     338
Ejector Efficiency     339
Design of Nozzles and Venturis     340
Ejector Risers and Swings     344
Ejector Headers     344
Ejector Installation     345
Ejectors and Groundwater Quality     345
Ejectors and Soil Stabilization     349
Drilled Horizontal Wells     349
Trencher Drains     355
Groundwater Cutoff Structures     358
Cutoff Terminology and Efficiency     358
Steel Sheet Piling     358
Slurry Trenches     367
Slurry Diaphragm Walls     379
Secant Piles     390
Deep Soil Mixing     398
Tremie Seals     405
Grouting Methods     410
Permeation Grouting     410
Jet Grouting     439
Rock Curtain Grouting     456
Grouting of Structures and Flowpaths     474
Dewatering and Groundwater Control for Soft Ground Tunneling     491
Soft Ground Tunneling Methods with Conventional Dewatering     491
Ground Behavior     495
Mixed-face Ground Conditions     497
Dewatering Design for Tunnels     497
Methods of Tunnel Predrainage     499
Tunneling Techniques with Built-in Groundwater Control     500
Compressed Air Tunneling     504
Dewatering of Access Shafts, Penetrations, and Starter Tunnels     505
Ground Freezing     508
General Principles     508
Freezing Applications     509
Freezing Methods and Equipment     515
Ground Freezing and Soils     528
Design     533
Effect of Groundwater Movement     534
Ground Movement Potential as a Result of Artificial Freezing     534
Artificial Recharge     539
Recharge Applications     539
Design Objectives     540
Potential Problems with Recharge Water and Plugging of Wells     541
Sources of Recharge Water     543
Treatment of Recharge Water     544
Construction of Recharge Systems     545
Operation and Maintenance of Recharge Systems     550
Permits for Recharge Operations     550
Electrical Design for Dewatering Systems     556
Electrical Motors     556
Motor Controls     561
Power Factor     564
Electric Generators      564
Switchgear and Distribution Systems     566
Grounding of Electrical Circuits     570
Cost of Electrical Energy     570
Long-term Dewatering Systems     572
Types of Long-term Systems     572
Access for Maintenance     572
Instrumentation and Controls     575
Dewatering Costs     577
Format of the Estimate     577
Basic Cost Data     577
Mobilization     578
Installation and Removal     578
Operation and Maintenance     579
Summary     581
Specialty Dewatering Subcontractor Quotations     581
Dewatering Specifications, Allocation of Risk, Dispute Avoidance, and Resolution of Disputes     584
Performance Specifications     585
Owner-designed Dewatering Systems     586
Specified Minimum Systems     586
Dewatering Submittals     586
Third-party Damage Caused by Dewatering     587
Differing Site Conditions     588
Disputes Review Board     595
Appendix A     597
Appendix B     603
Appendix C     620
Index     623