Applied Geotechnics for Construction Projects, Volume 4

Ammar Dhouib, doctor of civil engineering specializing in soil mechanics, is a lecturer and professor of geotechnics at Polytech Sorbonne University, Paris, France. He is also a geotechnical expert at the VINCI construction group and a justice expert at the Court of Appeal in Versailles. His research interests focus on geotechnics, and he has authored or co authored five books on this topic.

• Foreword xiPhilippe GUILLERMAIN and François SCHLOSSEREntrepreneur’s Tribune: Geotechnics is at the Heart of Our Projects xiiiPascal LEMOINE and Eric DURANDPreface xvAcknowledgments xxiSymbols and Notations xxiiiIntroduction lviiChapter 1 Active and Passive Earth Pressures: Earth Retaining Structures 11.1 Active and passive earth pressures 11.1.1 Introduction 11.1.2 State of soils at rest 21.1.3 Active earth pressure in the soil 41.1.4 Passive earth pressure in the soil 81.1.5 Active and passive earth pressure forces 101.1.6 Active–passive pressure and back passive pressure: choice of incline 131.1.7 Active–passive earth pressures: specific cases 161.1.8 Effect of overloads 191.1.9 French practice 231.2 Behavior and sizing of earth retaining structures 251.2.1 Introduction: designing retaining structures 251.2.2 Classes of earth retaining structures 251.2.3 Limit conditions 271.2.4 History and path of the stresses 281.2.5 Behavior of rigid and flexible walls 311.3 Designing approaches 321.3.1 Classic failure analysis 331.3.2 Reaction coefficient method 341.3.3 Finite elements calculations 341.4 Method based on the reaction coefficient 351.4.1 Principle of the method 351.4.2 Soil/retaining structure reaction curve 361.4.3 Resolution method 391.4.4 Approaches for evaluating the reaction coefficient 401.5 The specific case of reinforced excavations 431.5.1 The principle of reinforcement 431.5.2 Horizontal stresses distribution diagrams 441.6 Subgrade stability 461.6.1 “Solid piping” 461.6.2 “Boiling” phenomenon 481.7 Applications 491.7.1 “Gravity” earth-retaining wall in a homogeneous soil mass 491.7.2 Study of a sheet piling using a classic failure analysis 611.7.3 Study of an advance shoring excavation 701.7.4 Project for a retaining diaphragm anchored by active tie rods 781.8 Incidents: they can happen quickly! 1031.8.1 Case of a sheet piling fixed in chalk 1031.8.2 Retaining diaphragm walls with tie rods and anchored in a substratum 1041.8.3 Alternate pass shell technique 1051.9 Appendices 1071.9.1 Appendix 1: Ground friction/strut sealing 1071.9.2 Appendix 2: Steel reinforcement of continuous walls 1131.9.3 Appendix 3: Stability of the tie rod mass (Kranz approach) 1151.9.4 Appendix 4: Stability and comparison of approaches in earthquake calculation for retaining gravity walls 1161.10 References 119Chapter 2 Soil Reinforcement and Improvement 1232.1 Overview 1232.1.1 Introduction 1232.1.2 Historical and geographic context of the development of soil improvement techniques 1252.1.3 The field and limits of the application of the different techniques 1282.2 Reinforced Earth 1312.2.1 Process 1312.2.2 Construction method and displacement field 1312.2.3 Displacement field 1322.2.4 The surface of potential failure and tensile stresses in the reinforcement 1332.2.5 Location and distribution of maximum tension in an RE wall 1352.2.6 Friction between the soil and the RE reinforcement 1362.2.7 Designing RE structures 1372.2.8 The behavior of Reinforced Earth under triaxial shear testing 1402.3 In situ soil nailing 1412.3.1 The principles of nailing 1412.3.2 The behavior of nailed walls 1432.3.3 The interaction between the soil and the rod: the forces occurring around the rigid rod 1452.3.4 The dimensions of the structures made from nailed earth 1472.4 Soil reinforcement with micropiles 1562.4.1 The principle of micropiles 1562.4.2 Types of forces on micropiles and an assessment of possible actions 1562.4.3 Theoretical study of an isolated micropile under centered axial load 1582.4.4 An isolated micropile that causes a lateral reaction in the soil 1602.4.5 Buckling of a micropile embedded into the soil 1622.4.6 The effect of a group or a network: efficiency coefficient (kef) 1632.4.7 Designing structures reinforced by micropiles 1652.4.8 The justification of Eurocode micropile 1682.5 Applications 1702.5.1 The mixed structure: Reinforced Earth and nailed walls 1702.5.2 Construction crane on top of a group of micropiles 1822.5.3 Comparing some French guidelines 1892.6 Other techniques of in situ soil improvement 1942.6.1 Compaction through vibration 1942.6.2 Dynamic compaction 1982.6.3 Soil–cement mortar columns carried out by jet grouting 2002.6.4 Stone columns 2032.6.5 In situ soil improvement through the use of rigid inclusions 2102.6.6 Deep compaction/solid injection 2132.6.7 Mixing the soil with a binder: the lime–cement column 2162.6.8 Consolidation by pre-loading 2182.6.9 Vacuum consolidation 2222.6.10 Other techniques 2232.6.11 Classical injections 2242.6.12 Soil freezing 2262.6.13 Some economic data 2282.7 Approaches to design 2312.8 Applications 2322.8.1 The study of embankment on stone columns 2322.8.2 Study of an industrial paving on vertical rigid inclusions topped by stone columns 2372.8.3 Reduction of the risk of liquefication with the vibro stone columns 2422.8.4 The behavior of rigid inclusions under general rafts 2462.9 A what not to do! 2492.9.1 Case 1: building on stone columns 2492.9.2 Data relative to the soil in case 1 2492.9.3 Improving soils with stone columns (case 1) 2502.9.4 Case 2: store with semi-rigid inclusions 2532.9.5 Others (“school case”) 2532.10 Appendices 2532.10.1 Appendix 1: Sizing chart of the lateral limit friction between the soil/nail (Clouterre 1991) 2532.10.2 Appendix 2: Practical sizing charts of stone columns 2552.10.3 Appendix 3: Sizing charts for the global safety coefficient of embankments on soil treated with stone columns 2582.10.4 Appendix 4: Structural verification of the support plate and the tie rod beams 2622.11 References 265Chapter 3 Underground Works: Convergence–Confinement Method 2733.1 Introduction 2733.1.1 Underground cavities 2743.1.2 Definition of a tunnel and its supporting structures 2753.2 Failure area at the vault of the tunnel and forces 2763.2.1 Failure area at the vault of the tunnel 2763.2.2 Forces on the supporting structures 2773.3 Displacement of the receiving terrains 2783.3.1 Convergence of tunnels and extrusion 2783.3.2 Surface displacement (“subsidence”) 2793.4 Mechanic behavior of tunnels 2803.4.1 “Convergence–confinement” method 2813.4.2 Simple methodology for estimating settlement 2833.5 Dig methods and retaining structure types 2863.5.1 Dig methods 2863.5.2 Requirements and support types 2863.6 Practical applications 2883.6.1 Estimating the settlements empirically 2883.6.2 Some practical results relating to surface settlement 2953.6.3 Modeling with plane deformations 2973.7 References 299French, European and ISO Standards in the Field of Geotechnics 303Index 335Summaries of Other Volumes 337