Advanced Soil Mechanics Stefan Van Baars © Edited and published by Stefan Van Baars Edition May 2016 Key words: soil mechanics, foundation engineering, tunnelling PREFACE This book Advanced Soil Mechanics is part of the education of Civil Engineering at the faculty of Science, Technology and Communication of the University of Luxembourg It can be seen as a continuation of the introductory courses of Soil Mechanics, as for example written down in the book Soil Mechanics of A Verruijt This book contains the major principles and design methods used in Geotechnical Engineering, such as soil improvement, geotextiles, tunnelling, shallow and pile foundation, sheet piles, anchors, struts and dewatering Probably a title for this book like “Geotechnical Engineering” would have been better, but the current title “Advanced Soil Mechanics” expresses more the continuation of the book of A Verruijt and expresses more the mechanical focus of this book The chapters 14-22, 33-39, 45-46, 51-54, are copied from the book of A Verruijt and updated as a bridge to this book Some other parts of this book have been collected from other sources; books, internet, other lecture notes, including my own; and translated from Dutch, German or French into English Since this book contains pictures and parts of text from many different authors, which are mixed, sorted and changed all over, it is impossible to compile a complete track record of all references In some cases the sources will remain unknown unfortunately My special thanks go out to Prof Dr Ir A Verruijt, who taught me the fundamentals of Soil Mechanics and to Prof Drs Ir J Vrijling who taught me the importance of simple hand design engineering and the danger of experience, which is not fully understood This book tries to teach their visions in Advanced Soil Mechanics Luxembourg, May 2012 Stefan Van Baars Cover Photo from Neidhardt Grundbau Gmbh, Germany CONTENT I SOIL IMPROVEMENT 11 Introduction 12 Mechanical compaction 13 2.1 Surface compaction 13 2.2 In-depth compaction 15 Injection techniques 17 3.1 Permeation grouting 18 3.2 Jet-grouting 19 3.3 Fracture grouting 20 3.4 Compaction grouting 21 Dewatering & drains 22 4.1 Introduction 22 4.2 Vertical drainage 23 Ground freezing 25 5.1 Introduction 25 5.2 Brine freezing (indirect cooling) 26 5.3 Nitrogen freezing (direct cooling) 26 5.4 Thermic Design 27 Geotextiles and reinforced soil 29 6.1 Geotextiles 29 6.2 Reinforced soil / Terre armée 31 Ground exchange 34 7.1 Natural soils 34 7.2 Artificial heavy or light products 36 II TUNNELLING 37 Tunnel types 38 Cut & cover tunnel 40 9.1 Open building pit 40 9.2 Classical cut & cover 41 9.3 Aqueduct 42 9.4 Wall-Roof method 43 10 Tunnel Boring Machine (TBM) 46 10.1 Open face TBM 47 10.2 Hydro shield or slurry shield (SS) TBM 47 10.3 Earth Pressure Balanced shield (EPB) TBM 49 10.4 Hard rock TBM 49 10.5 Support pressure 50 10.6 Pneumatic caisson 51 10.7 Settlements 51 11 Drill & blast (rock) tunnelling 54 11.1 German Method or Core Method 55 11.2 Old Austrian Tunnelling Method or Old ÖTM 55 11.3 New Austrian Tunnelling Method or NÖTM 55 12 Immersed tunnel 58 12.1 Construction method 58 12.2 Chin-nose and jack-leg support 60 12.3 Advantages and disadvantages 61 13 Jacked box tunnel 63 III SHALLOW FOUNDATIONS 65 14 Types of shallow foundations 66 15 Elastic stresses and deformations 68 16 Boussinesq 70 17 Flamant 74 18 Deformation of layered soil 78 19 Bearing capacity of a strip footing 81 19.1 Lower bound 82 19.2 Upper bound 84 20 Prandtl & Nc 86 21 Reissner & Nq 89 22 Meyerhof & N 90 23 Table of the bearing capacity factors 91 24 Correction factors 92 24.1 Inclination factors i 92 24.2 Shape factors s 93 25 CPT, undrained shear strength and Prandtl 95 IV PILE FOUNDATIONS 97 26 Cone Penetration Test (CPT) 98 27 Compression piles 102 27.1 Pile types 102 27.2 Bearing capacity 109 27.3 CPT, SPT and HDP 110 27.4 Tip resistance using Meyerhof (Prandtl, Terzaghi or Brinch Hansen) 111 27.5 Tip resistance using a CPT method (Koppejan) 112 27.6 Shaft resistance 115 27.7 Settlement of piles 119 28 Tension piles 120 28.1 Differences between tension and compression piles 120 28.2 Reduction of the cone value qc due to excavation 120 28.3 Reduction of cone resistance due to tensile pile force 121 28.4 Clump criterion 122 28.5 Edge Piles 123 28.6 MV-pile or Jacket-grouted pile 123 V UNDERGROUND MEGASTRUCTURES 125 29 Underground megastructures 126 30 Sustainable resources 130 VI BUILDING PIT 131 31 Building pit 132 31.1 Introduction 132 31.2 Pit collapse 133 31.3 Pit design 135 VII WALLS AND LATERAL STRESS 137 32 Walls 138 32.1 Wall types 138 32.2 Soldier pile wall (Berliner wall) 139 32.3 Sheet pile wall 140 32.4 Combi wall 141 32.5 Bored pile wall 142 32.6 Diaphragm wall 143 33 Lateral stresses in soils 147 33.1 Coefficient of lateral earth pressure 147 33.2 Elastic material 149 33.3 Elastic material under water 150 34 Rankine 151 34.1 Mohr-Coulomb 151 34.2 Active earth pressure 153 34.3 Passive earth pressure 154 34.4 Neutral earth pressure 156 34.5 Menard-penetrometer and CAMKO-pressuremeter 156 34.6 Groundwater 157 35 Coulomb 159 35.1 Active earth pressure 159 35.2 Passive earth pressure 161 36 Tables for lateral earth pressure 164 36.1 The problem 164 36.2 Example 165 36.3 Tables 166 37 Sheet pile walls 170 37.1 Homogeneous dry soil 170 37.2 Pore pressures 174 38 Blum 177 39 Sheet pile wall in layered soil 182 39.1 39.2 39.3 39.4 39.5 Computer program 182 Computation of anchor plate 183 Horizontal bedding constants for subgrade reaction models 184 Finite Element Modelling 186 Example quick design 186 40 Sheet pile profiles 188 VIII ANCHORS, STRUTS AND WALES 191 41 Supports 192 42 Anchors 193 42.1 Anchoring 193 42.2 Anchor installation 195 42.3 Soil nailing 199 42.4 Holding capacity of anchor plate 201 42.5 Holding capacity of a grouted anchor 203 42.6 Overall stability 206 43 Struts 208 44 Wales 210 IX FLOORS 213 45 Floatation & Archimedes 214 46 Natural floor & heave 215 47 Unsupported under water concrete floor 216 48 Supported under water concrete floor 218 48.1 General 218 48.2 Floatation of the floor 219 48.3 Transfer of forces to piles & fracture of the pile joint 220 48.4 Fracture of the floor 221 X GLOBAL STABILITY & FAILURE 225 49 Failure modes 226 50 Global translation (sliding) 227 51 Global rotation (circular sliding) 229 51.1 Safety factor 230 51.2 Fellenius 231 51.3 Bishop 233 51.4 Global failure 234 XI DEWATERING 237 52 Groundwater flow 238 52.1 Hydrostatics 238 52.2 52.3 52.4 52.5 Groundwater head 239 Darcy 239 Permeability 240 Flow in a vertical plane 241 53 Flow net 243 53.1 Potential and stream function 243 53.2 Flow under a structure 245 54 Flow towards well 248 54.1 Confined aquifer 248 54.2 Unconfined aquifer 250 54.3 Semi-confined aquifer 252 54.4 Superposition 253 54.5 Examples 257 55 Dewatering 259 55.1 Open dewatering and wellpoint drainage 259 55.2 Dewatering problems 261 55.3 Hindrance for the surroundings 261 XII SAFE DESIGN 263 56 Limit states and design rules 264 56.1 Limit states 264 56.2 Design rules 265 57 Material and load factors 266 57.1 Design theory 266 57.2 Load factors 268 57.3 Material factors 269 57.4 Inadequate standards 270 58 Control sensors 271 10 ... published by Stefan Van Baars Edition May 2016 Key words: soil mechanics, foundation engineering, tunnelling PREFACE This book Advanced Soil Mechanics is part of the education of Civil Engineering... of Soil Mechanics, as for example written down in the book Soil Mechanics of A Verruijt This book contains the major principles and design methods used in Geotechnical Engineering, such as soil. .. book tries to teach their visions in Advanced Soil Mechanics Luxembourg, May 2012 Stefan Van Baars Cover Photo from Neidhardt Grundbau Gmbh, Germany CONTENT I SOIL IMPROVEMENT 11 Introduction