RETAINING-WALLS FOR EARTH
Chapter 1 Active and Passive Earth Pressures: Earth Retaining Structures 1 11 Active and passive earth pressures 1 111 Introduction 1 112 State of soils at rest 2 113 Active earth pressure in the soil 4 114 Passive earth pressure in the soil 8 115 Active and passive earth pressure forces 10 116 Active–passive pressure and back passive pressure: choice of incline 13 117 Active–passive earth pressures: specific cases 16 118 Effect of overloads 19 119 French practice 23 12 Behavior and sizing of earth retaining structures 25 121 Introduction: designing retaining structures 25 122 Classes of earth retaining structures 25 123 Limit conditions 27 124 History and path of the stresses 28 125 Behavior of rigid and flexible walls 31 13 Designing approaches 32 131 Classic failure analysis 33 132 Reaction coefficient method 34 133 Finite elements calculations 34 14 Method based on the reaction coefficient 35 141 Principle of the method 35 142 Soil/retaining structure reaction curve 36 143 Resolution method 39 144 Approaches for evaluating the reaction coefficient 40 15 The specific case of reinforced excavations 43 151 The principle of reinforcement 43 152 Horizontal stresses distribution diagrams 44 16 Subgrade stability 46 161 “Solid piping” 46 162 “Boiling” phenomenon 48 17 Applications 49 171 “Gravity” earth-retaining wall in a homogeneous soil mass 49 172 Study of a sheet piling using a classic failure analysis 61 173 Study of an advance shoring excavation 70 174 Project for a retaining diaphragm anchored by active tie rods 78 18 Incidents: they can happen quickly! 103 181 Case of a sheet piling fixed in chalk 103 182 Retaining diaphragm walls with tie rods and anchored in a substratum 104 183 Alternate pass shell technique 105 19 Appendices 107 191 Appendix 1: Ground friction/strut sealing 107 192 Appendix 2: Steel reinforcement of continuous walls 113 193 Appendix 3: Stability of the tie rod mass (Kranz approach) 115 194 Appendix 4: Stability and comparison of approaches in earthquake calculation for retaining gravity walls 116 110 References 119 Chapter 2 Soil Reinforcement and Improvement 123 21 Overview 123 211 Introduction 123 212 Historical and geographic context of the development of soil improvement techniques 125 213 The field and limits of the application of the different techniques 128 22 Reinforced Earth 131 221 Process 131 222 Construction method and displacement field 131 223 Displacement field 132 224 The surface of potential failure and tensile stresses in the reinforcement 133 225 Location and distribution of maximum tension in an RE wall 135 226 Friction between the soil and the RE reinforcement 136 227 Designing RE structures 137 228 The behavior of Reinforced Earth under triaxial shear testing 140 23 In situ soil nailing 141 231 The principles of nailing 141 232 The behavior of nailed walls 143 233 The interaction between the soil and the rod: the forces occurring around the rigid rod 145 234 The dimensions of the structures made from nailed earth 147 24 Soil reinforcement with micropiles 156 241 The principle of micropiles 156 242 Types of forces on micropiles and an assessment of possible actions 156 243 Theoretical study of an isolated micropile under centered axial load 158 244 An isolated micropile that causes a lateral reaction in the soil 160 245 Buckling of a micropile embedded into the soil 162 246 The effect of a group or a network: efficiency coefficient (kef) 163 247 Designing structures reinforced by micropiles 165 248 The justification of Eurocode micropile 168 25 Applications 170 251 The mixed structure: Reinforced Earth and nailed walls 170 252 Construction crane on top of a group of micropiles 182 253 Comparing some French guidelines 189 26 Other techniques of in situ soil improvement 194 261 Compaction through vibration 194 262 Dynamic compaction 198 263 Soil–cement mortar columns carried out by jet grouting 200 264 Stone columns 203 265 In situ soil improvement through the use of rigid inclusions 210 266 Deep compaction/solid injection 213 267 Mixing the soil with a binder: the lime–cement column 216 268 Consolidation by pre-loading 218 269 Vacuum consolidation 222 2610 Other techniques 223 2611 Classical injections 224 2612 Soil freezing 226 2613 Some economic data 228 27 Approaches to design 231 28 Applications 232 281 The study of embankment on stone columns 232 282 Study of an industrial paving on vertical rigid inclusions topped by stone columns 237 283 Reduction of the risk of liquefication with the vibro stone columns 242 284 The behavior of rigid inclusions under general rafts 246 29 A what not to do! 249 291 Case 1: building on stone columns 249 292 Data relative to the soil in case 1 249 293 Improving soils with stone columns (case 1) 250 294 Case 2: store with semi-rigid inclusions 253 295 Others (“school case”) 253 210 Appendices 253 2101 Appendix 1: Sizing chart of the lateral limit friction between the soil/nail (Clouterre 1991) 253 2102 Appendix 2: Practical sizing charts of stone columns 255 2103 Appendix 3: Sizing charts for the global safety coefficient of embankments on soil treated with stone columns 258 2104 Appendix 4: Structural verification of the support plate and the tie rod beams 262 211 References 265 Chapter 3 Underground Works: Convergence–Confinement Method 273 31 Introduction 273 311 Underground cavities 274 312 Definition of a tunnel and its supporting structures 275 32 Failure area at the vault of the tunnel and forces 276 321 Failure area at the vault of the tunnel 276 322 Forces on the supporting structures 277 33 Displacement of the receiving terrains 278 331 Convergence of tunnels and extrusion 278 332 Surface displacement (“subsidence”) 279 34 Mechanic behavior of tunnels 280 341 “Convergence–confinement” method 281 342 Simple methodology for estimating settlement 283 35 Dig methods and retaining structure types 286 351 Dig methods 286 352 Requirements and support types 286 36 Practical applications 288 361 Estimating the settlements empirically 288 362 Some practical results relating to surface settlement 295 363 Modeling with plane deformations 297 37 References 299 French, European and ISO Standards in the Field of Geotechnics 303