Geosynthetics and their Applications

Contents

1 Fundamentals of geosynthetics 1

S. K. Shukla

1.1. Introduction 1

1.2. Definitions and classification 1

1.3. Historical development 8

1.4. Basic functions and selection 10

1.5. Raw materials and manufacturing processes 13

1.6. Properties and test methods 18

1.6.1. Physical properties 19

1.6.2. Mechanical properties 20

1.6.3. Hydraulic properties 28

1.6.4. Endurance and degradation properties 37

1.7. Application areas 43

1.8. Standards 46

1.9. Concluding remarks 50

References 51

2 Soil- -geosynthetic interaction 55

M. L Lopes

2.1. Introduction 55

2.2. Granular soil behaviour 56

2.3. Soil-geosynthetic interaction mechanisms 57

2.4. Soil-geosynthetic interface resistance 58

2.5. Factors influencing soil-geosynthetic interaction 62

2.5.1. Soil particle size 62

2.5.2. Confinement stress 66

2.5.3. Soil density 67

2.5.4. Geosynthetic structure 68

2.6. Laboratory tests for the quantification of soil-geosynthetic interface resistance 71

2.6.1. Direct shear test 71

2.6.2. Pullout test 72

2.7. Concluding remarks 78

References 78

3 Retaining walls 81

B. M. Das

3.1. Introduction 81

3.2. Design considerations 81

3.2.1 Stability 81

3.2.2 Lateral earth pressure 81

3.2.3. Tie force 85

3.3. Design procedure for retaining walls with geotextile reinforcement 85

3.3.1. General 85

3.3.2. Internal stability 85

3.3.3. External stability 87

3.4. Design procedure for retaining walls with geogrid reinforcement 92

3.5. Concluding remarks 92

References 93

4 Embankments 95

E. M. Palmeira

4.1. Introduction 95

4.2. Geosynthetics as a basal reinforcement in embankments 95

4.2.1. Reinforcement roles and aspects to be considered in the analysis 95

4.2.2. Design approaches for reinforced embankments 98

4.2.3. Choice of the reinforcement 108

4.2.4. Anchorage length of the reinforcement 109

4.2.5. Additional remarks on analysis and design 109

4.3. Geosynthetics for drainage in embankments 114

4.3.1. Introduction 114

4.3.2. Geosynthetic drainage blanket at the base of the embankment 114

4.3.3. Geosynthetic vertical drains 115

4.4. Concluding remarks 118

References 119

5 Shallow foundations 123

S. K. Shukki

5.1. Introduction 123

5.2. Functions and mechanisms 123

5.3. Reinforcing patterns 127

5.4. Modes of failure 127

5.5. Model tests 128

5.5.1. Reinforced granular soil 128

5.5.2. Reinforced clay 132

5.5.3. Reinforced granular fill soft foundation soil system 134

5.6. Load-bearing capacity analysis 138

5.6.1. Reinforced granular fill 139

5.6.2. Reinforced clay 143

5.6.3. Reinforced granular fill soft foundation soil system 143

5.7. Settlement analysis 148

5.8. Field applications 153

5.9. Concluding remarks 157

References 158

6 Unpaved roads 165

P. L. Bourdeau and A. K. Ashmawy

6.1. Introduction 165

6.2. Unpaved road reinforcement 166

6.2.1. Interactions under monotonic loading 166

6.2.2. Effect of repeated loading 169

6.2.3. Design for reinforcement 171

6.3. Concluding remarks 180

References 181

7 Paved roads 185

s. w. Perkins, R. R. Berg and B. R. Christopher

7.1. Introduction 185

7.2. Distress features and their relationship to geosynthetics 185

7.3. Geosynthetic functions 187

7.3.1. Reinforcement 187

7.3.2. Separation 189

7.3.3. Filtration 192

7.3.4. Drainage 193

7.4. History and experimental evidence for base reinforcement 193

7.5. Summary of critical design variables for base reinforcement 195

7.6. Design solutions and approaches for base reinforcement 195

7.7. Concluding remarks 198

References 199

8 Railway tracks 203

S. A. (Harry) Tan

8.1. Introduction 203

8.2. Track components and substructure 203

8.2.1. Subgrade 203

8.2.2 Subballast 204

8.2.3. Ballast 205

8.3. Functions of geosynthetics 207

8.3.1. Separation 208

8.3.2. Filtration 208

8.3.3. Confinement/ reinforcement 209

8.3.4. Drainage 209

8.4. Properties of geosynthetics 210

8.5. Design procedure 212

8.6. Installation of geosynthetics 213

8.7. Case histories in railway track stabilization 214

8.7.1. Experience from Canada and the USA 214

8.7.2. European experience 215

8.7.3. Indian experience 216

8.8. Geosynthetic drains for track drainage applications 216

8.8.1. Sources of water 216

8.8.2. Track drainage requirements 217

8.8.3. Side drains 217

8.8.4. Drainage of subgrade seepage 219

8.9. Concluding remarks 220

References 221

9 Slopes – erosion control 223

T. S. Lngold

9.1. Introduction 223

9.2. Interaction of rain and river erosion 223

9.3. Mechanics of surface erosion 224

9.4. Classification of erosion control systems 225

9.5. Design approach 227

9.6. Study of short-term yield factors 228

9.7. Results from various field and laboratory tests 231

9.8 Concluding remarks 234

References 234

10 Slopes – stabilization 237

S. K. Shukla

10.1. Introduction 237

10.2. Types and orientations of geosynthetics 238

10.3. Modes of failure 238

10.4. Stability analysis of reinforced slopes 239

10.4.1. Limit equilibrium method 239

10.4.2. Limit analysis method 241

10.4.3. Slip line method 242

10.4.4. Finite element method 242

10.5. Model tests 242

10.6. Stabilization methods in practice 245

10.6.1. Method suggested by Broms and Wong (1986) 245

10.6.2. Method suggested by Koerner (1984) and Koerner and Robins (1986) 248

10.6.3. Methods based on the construction of reinforced soil structures 250

10.7. Concluding remarks 255

References 255

11 Landfills 259

H. Zanzinger and E. Gartung

11.1. Introduction 259

11.2. Multibarrier concept 260

11.3. Landfill categories 261

11.4. Basal lining systems 262

11.4.1. Functional layers 262

11.4.2. Concept of the composite liner 262

11.4.3. Alternative liners 263

11.5. Components of the composite liner 264

11.5.1. Compacted clay liner 264

11.5.2. Geomembrane 264

11.5.3. Protective layer for the geomembrane 266

11.6. Construction of liners 267

11.6.1. Preparations 267

11.6.2. General aspects of installation 268

11.6.3. Placement of the geomembrane 268

11.6.4. Quality assurance 270

11.7. Leachate collection and removal 271

11.7.1. Drainage blanket and filters 271

11.7.2. Leachate collection pipes and access shafts 271

11.7.3. Consequences for the basal seal 272

11.8. Cover system 272

11.8.1. General 272

11.8.2. Regulating soil and gas venting layer 273

11.8.3. Mineral sealing layer 273

11.8.4. Geosynthetic clay liners 274

11.8.5. Geomembranes 274

11.8.6. Dewatering of cover systems 275

11.8.7. Drainage geocomposites 276

11.9. Concluding remarks 277

References 277

12 Earth dams 281

D. N. Singh and S. K. Shukla

12.1. Introduction 281

12.2. Use of conventional materials 282

12.3. Use of geosynthetics 285

12.3.1. Geosynthetics as a barrier to fluid 285

12.3.2. Geosynthetics as a drainage channel 287

12.3.3. Geosynthetics as a filter 289

12.3.4. Geosynthetics as a protective layer 291

12.3.5. Geosynthetics as a reinforcement 291

12.3.6. Geosynthetics as an erosion control layer 293

12.4. River bed and bank protection 295

12.5. Design considerations 295

12.6. Concluding remarks 296

References 296

13 Containment ponds, reservoirs and canals 299

C. Duquennoi

13.1. Introduction 299

13.2. Historical background 299

13.3. Design of geosynthetic systems 301

13.3.1. Subgrade preparation 301

13.3.2. Underliner drainage and protection 302

13.3.3. Lining systems 302

13.3.4. Overliner protection and cover 304

13.3.5. Singularities 305

13.4. Case studies 306

13.4.1. Containment ponds 306

13.4.2. Reservoirs 309

13.4.3. Canals 315

13.5. Concluding remarks 322

13.5.1. Acknowledgements 322

References 323

14 Geosynthetic-reinforced soil walls and slopes – seismic aspects 327

R. J. Bathurst, K. Hatami and M. C. Alfaro

14.1. Introduction 327

14.2. Material properties under dynamic loading 328

14.2.1. Soil 328

14.2.2. Geosynthetic reinforcement 331

14.2.3. Interface properties 336

14.3. Seismic analysis and design of walls and slopes 341

14.3.1. Pseudo-static methods 341

14.3.2. Pseudo-dynamic methods 355

14.3.3. Displacement calculations 357

14.3.4. Dynamic analysis using numerical techniques 362

14.4. Physical testing of model walls and slopes 373

14.4.1. Gravity (1g) shaking and tilt table tests 373

14.4.2. Centrifuge shaking table tests 378

14.5. Seismic buffers 379

14.6. Observed performance of reinforced soil walls and slopes during earthquakes 379

14.6.1. North American experience (Northridge 1994 and Loma Prieta 1989) 379

14.6.2. Japanese experience (Hanshin 1995) 380

14.7. Concluding remarks 381

14.7.1. Acknowledgements 383

References 383

15 Geosynthetic applications – general aspects and selected case studies 393

S. K. Shukla

15.1. Introduction 393

15.2. General guidelines 393

15.3. Quality control and in-situ monitoring 399

15.4. Cost analysis 400

15.5. General problems 405

15.6. Selected case studies 406

15.6.1. Retaining walls and steep slopes 406

15.6.2. Landfills 409

15.6.3. Pipeline and drainage systems 411

15.6.4. Slopes – erosion control 412

15.6.5. Irrigation channels and reservoirs 413

15.6.6. Earth dams 413

15.6.7. Roads 414

15.6.8. Tunnels 416

15.7. Concluding remarks 416

References 417

Index 421