CONTENT: Preface vii Acknowledgements ix 1 Introduction 1 1.1 Initial Developments 1 1.1.1 Geosynthetics 1 1.2 Recent Developments 2 1.2.1 Reinforced soil 2 1.2.2Geosynthetics 4 1.3 Applications and Potential 5 1.3.1 Soil reinforcement function 5 1.3.2Separator function 6 1.3.3Filtration function 7 1.3.4Drainage function 7 1.3.5Barrier function 7 1.4 Advantages of the Techniques 8 2 Design Principles and Influencing Factors 12 2.1 Introduction 12 2.2 Mechanism of Reinforced Soil 12 2.3 Factors affecting Behaviour and Performance 17 2.3.1 Reinforcement 17 2.3.2Reinforcement distribution 20 2.3.3Soil 20 2.3.4Soil state 23 2.3.5Construction factors 23 2.4 Soil-Reinforcement Interactions 23 2.5 Design of Spacing and Layout 24 3 Materials and Material Properties 25 3.1 Introduction 25 3.2 Materials 25 3.2.1 Metallic reinforcement 25 3.2.2Polymeric materials 27 3.3 Concluding Remarks 40 4 Improvement of Bearing Capacity 44 4.1 Introduction 44 4.2 Modes of Failure 44 4.3 Determination of Force Induced in Reinforcement Ties 46 4.3.1 Location of failure surface 46 4.3.2Tension failure and pull-out considerations 48 4.3.3Calculation of minimum length of ties 51 4.3.4Curtailment of pull-out length of reinforcement 52 4.4 Guidelines on the Use of Geogrids 53 4.5 Bearing Capacity Improvement in Soft Soils 54 4.5.1 Shear layer effect 56 4.5.2Confinement effect 57 4.5.3Surcharge effect 57 4.6 Concluding Remarks 57 5 Design of Reinforced Soil Slopes 59 5.1 Introduction 59 5.2 General Approach 59 5.3 Jewell's Method 62 5.4 Choice of Design Values for Parameters and Use of Charts 64 5.4.1 Soil properties 65 5.4.2Properties of reinforcement materials65 5.4.3Interaction parameters 68 5.5 Steps for Simplified Design 74 5.6 Design Example 75 5.6.1 Design steps 76 5.7 Role of Compaction Stresses 79 5.8 Concluding Remarks 79 6 Design of Reinforced Soil Retaining Walls 81 6.1 Introduction81 6.2 Mechanics of Reinforced Soil 81 6.2.1 Enhancement of shear strength 81 6.2.2Available reinforcement force 82 6.2.3Stress-strain behaviour82 6.3 Components of Reinforced Soil Walls82 6.3.1 Reinforcement 82 6.3.2Facing 84 6.3.3Backfill 84 6.4 Principles of Design 85 6.4.1 Preliminary dimensions 86 6.4.2Factors of safety 86 6.4.3External stability87 6.4.4InternaJ stability90 7 Embankments on Soft Soil 105 7.1 Introduction 105 7.2 Analysis 106 7.2.1Internal stability 108 7.2.2Overall stability 109 7.2.3Stability in the foundation 110 7.3 Influence of Reinforcement Extensibility 111 7.4 Relationships for Design 112 7.5 Deformation in Foundation 113 7.5.1Settlement analysis 113 7.6 Overall Stability with respect to Bearing 113 7.7 Safety Factors 114 8 Soil Nailing 118 8.1 Introduction 118 8.2 Overview 119 8.2.1Technique 119 8.2.2In situ ground (Soil) 120 8.2.3Nails 121 8.2.4Nail placement 121 8.2.5Facing 122 8.2.6Drainage 122 8.3 Advantages and Disadvantages of Soil Nails 122 8.4 Soil-Nail Interaction 123 8.5 Engineering Behaviour 123 8.6 Design Procedure 124 8.7 Design based on Charts 126 8.7.1 Gassier method 126 8.7.2Davis method 129 8.8 Role of Numerical Methods 132 8.9 Behaviour in Seismic Conditions 132 8.10 Concluding Remarks 133 9 Use of Geosynthetics for Filtration and Drainage 135 9.1 Introduction135 9.2 Background 135 9.3 Applications 136 9.4 Conventional Granular Filter Design Criteria 138 9.5 Geotextile Filter Requirements 138 9.6 Boundary Conditions139 9.7 Drain and Filter Properties139 9.8 Design Criteria .139 9.8.1 Soil retention criteria 139 9.8.2Geotextile permeability criteria143 9.8.3 Anti-clogging criteria 143 9.8.4Survivability criteria 145 9.8.5Durability criteria 146 10 Use of Geosynthetics in Roads 150 10.1 Introduction 150 10.2Geosynthetics in Roadways 150 10.3Applications 151 10.3.1 Temporary and permanent roads 151 10.3.2 Benefits 153 10.4Role of Subgrade Conditions 153 10.5Design154 10.6The Giroud and Noiray Approach 55 10.7Geotextile Survivability 159 10.8Application in Paved Roads 160 11 Geosynthetics in Landfills 162 11.1Introduction I62 11.2Typical Designs of Landfills 163 11.2.1 Landfill liners 163 11.2.2 Covers164 11.3Guidelines 165 11.3.1 EPA guidelines 165 11.3.2 Guidelines followed in Germany 167 11.3.3 Ministry of Environment and Forests (MoEF) guidelines 167 11.4Role of Geosynthetics 170 11.5 Barrier Walls for Existing Landfills and Abandoned Dumps175 11.6 Some Issues/Concerns in Usage 179 11.7 Conclusions 179 12 Natural Geotextiles 181 12.1 Introduction 181 12.2 Natural Fibres as Geotextiles 181 12.3 Factors Governing the Usage of Natural Geotextiles 182 12.4 Jute Fibres 183 12.4.1 Various products of jute 183 12.4.2 Advantages and disadvantages 184 12.4.3 Enhancing the durability of jute 187 12.4.4 Applications 187 12.5Coir Geotextiles 188 12.5.1 Products of coir 188 12.5.2 Advantages and disadvantages 189 12.5.3 Preservation 190 12.6Bamboo/Timber 190 12.6.1 Advantages and disadvantages 191 12.6.2 Preservation methods 192 12.7Combination of Geotextiles 193 12.8Concluding Remarks 195 Index 196