Cyclic Loading of Soils: from theory to design

Edited by

M. P. O 'REILLY and S. F. BROWN Department of Civil Engineering

University of Nottingham

Blackie G lasgow an d London

Van Nostrand Reinhold New York

Contents

l Cyclic loading in geotechnical engineering M. P. O'REILLY and S. F. BROWN

l

1. 1 lntroduction l 1.2 Definition of cyclic loading l l .3 Behaviour of soils under cyclic loading 2

1.3.1 Generai 2 1.3.2 Effect of stres rever als 3 1.3.3 Rate-dependent response of soil 9 1.3.4 Dynamic effects 10 1.3.5 Summary 11

1.4 Designing for cyclic loading ll 1.4.1 ldentifying situations where cyclic loading should be accounted for

in design Il 1.4.2 Principal ituations where cyclic loading is important 12 1.4.3 Other common situations in which cyclic loading plays an important

role 12 l.S Generai arrangement of the book 17

2 Approaches to modelling the cyclic stress-strain response of soils 19 D. MUIR WOOD Symbols

2.1 lnt roduction 2. 1.1 Philosophy of soil modelling 2. 1.2 Categorisation of models 2.1.3 lmportance of effective stresses

2.2 Models for monotonic loading 2.2. 1 Jngredients of a simple elastic-plastic mode! 2.2.2 Cam clay 2.2.3 Response of soil on unloading-reloading cycles 2.2.4 Elasticity

2.3 Models for cyclic loading 2.3.1 Viscoelasticity 2.3.2 Viscoplasticity 2.3.3 Damage models 2.3.4 Generalised stress reversal 2.3.5 Complete effective stres mode!

2.4 Concluding remarks References

3 Cyclic load testing of soils M. P. O 'REILLY

3.1 lntroduction 3.2 Laboratory element tests

3.2.1 lntroduction 3.2.2 Generai principles applicable to ali element tests 3.2.3 Specific element test arrangements 3.2.4 Loading systems

2 1 21 22 24 25 25 28 31 32 34 34 37 41 46 47 65 67

70

70 70 70 71 86 98

x CYCLIC LOADI G OF SOILS

3.3 /n-Sifll te IS 100 3.3. 1 lntroducrion 100 3.3.2 ln-siw non-dynamic loading tests HJO 3.3.3 Wave velocity testing 104 3.3.-l Empirica! test con ide red to provide an indication of the mecha nical

characte ristic of the ground 109 3.4 Phy ical mode l testing IlO

3.4. 1 ln troduction 110 3.-1.2 Centrifuge modelling 111 3.4.3 E arth gravity models 116 3.4.4 Dynamic cha racteristics testing 116 3.4.5 Case histo ries 117

Refe re nces ll7

4 Foundation design of offshore gravity structures 122 K. H. ANDERSEN

4 .1 lnt roduction 122 4 .2 T ypical o ffsho re gravity plarforms and soil conditions 122 4.3 Wave loads 129 4.4 Soil stres es and relevant laboratory tests 130 4.5 Bearing capacity 133

4 .5 .1 Cyclic shear stre ngth 134 4 .5 .2 Calcula tion procedure 139 4 .5 .3 Ve rification by mode! tests 143

4.6 Cyclic displacements and soil stiffness fo r dyna mic ana lyses 146 4 .6. 1 Stress- stra in behaviour unde r cyclic loading 148 4.6.2 Cyclic shear modulus to calculate cyclic displaceme nt 151 4.6.3 Shear modulus to calculate soil spring stiffnesses 154 4 .6.4 Calcula tio n procedure 157 4.6.5 Ve rification by proto type observation a nd mode l tests 158

4.7 Settlements due to cyclic loading 158 4. 7 . l Deve lopment of average shear strains during cycling 165 4.7.2 Pe rmane nt pore pressure due to cyclic loading 166 4.7.3 Procedure to calculate settlements due to shear strains unde r

undra ined cyclic loading 166 4.7.4 Calculation of settle me nts due todi sipa tion of to rm-induced

permanent pore pressure 169 Refe rences 171

5 The cyclic behaviour of large piles with special reference to offshore structures 174 R. J. JARDfNE

5.1 lntroduction 5. 1.1 a ture of the loading 5.1.2 Specia l features of offshore foundations 5 .1.3 The development of theory 5. 1.4 The contents of this chapte r

5 .2 Existing e mpirica! design methods 5.2. 1 Static ca pacity 5.2.2 The alpha me thod 5.2.3 The Ame rican Pe trole um lnstitute (API) codes 5.2.4 The be ta method 5.2.5 Predictio n o f static load - displaceme nt behaviour 5 .2.6 Current methods o f allowing fo r cyclic loading 5.2.7 Cyclic T - Z a nalyses: Matlock and Foo type models

174 174 175 176 177 177 177 177 178 179 181 184 187

CO TENTS

5.2.8 More advanced cyclic mode ls 5.2.9 Discussion

5.3 Unde rstanding static pile behaviour 5.3. 1 lntroduction 5.3.2 lnitial ground conditio n 5.3.3 Constitutive relation hips for the oils 5.3.4 Effects of pile installation -cavity expansion analy i 5.3.5 CEM ana lysis of post-insta llation equalisation 5.3.6 Strain pa th me thod 5.3.7 Expe ri ments with instrume nted pi les 5.3.8 Summa ry fo r equalised stress conditions 5.3.9 Pile loading- theory 5.3. 10 Continuum analyses-e la tic a nd e lastoplastic 5.3. 11 Simple shear analogies 5.3.12 Residua! fa bric 5.3.13 Srudying loading with instrume nted piles-dilatant clays 5.3.14 Contracta nt clays 5 .3.15 Predicting full-scale fo undation behaviour

5.4 Predicting fie ld behavio ur fro m o il e le ment tests 5 .4.1 Introduction 5.4.2 Undra ined cyclic behaviour of piles with a pre fo rmed residua!

surface 5.4.3 Cyclic soil behaviour 5.4.4 Inte raction diagra m 5.4.5 Permane nt stra ins 5.4.6 Effects of varying soil properties 5 .4. 7 Effects of cyclic pile toading on non-sliding contractive soils 5.4.8 Pe rmane nt e ffects of slow cycling 5.4.9 Effects of loading rate 5 .4.10 Projecting full-scale behavio ur 5.4. 11 Applying the results

5.5 Fie ld studies of cyclic pile behaviour 5.5.1 lntroduction 5.5.2 T ests at Cowde n 5.5.3 T ests at Ca nons Pa rk 5.5.4 The Haga programme

5.6 Summary Appendix 5 .I Cyclic mode l for inte rface sliding study 5. Ll Static loading cu rve 5. 1.2 Cyclic test data-changes in mean e ffective stress 5. 1.3 Additiona l assumptions for model 5.1.4 Predictions fo r cyclic capacity 5.1.5 The developme nt of pe rmanent stra in 5. 1.6 o n-unifo rm cycles Refe re nces

6 The design of pavement and rail track foundations S. F. BROWN and E. T. SELIG

6. 1 lntroduction 6.2 Principles of paveme nt design

6.2. 1 Failure mechanisms 6.2.2 The traditional e mpirica! approach 6.2.3 The rwo-layer syste m 6.2.4 Summary o f pave ment design procedures 6.2.5 Basic analytical approach

6.3 Mechanical prope rties o f soil 6.3. 1 ln-situ stress conditions

xi

187 190 190 190 190 19 1 192 194 194 197 200 20 1 201 202 203 204 205 206 209 209

210 2 11 212 215 216 217 218 221 222 229 230 230 230 232 233 236 239 239 239 242 244 244 245 245

249

249 253 253 254 256 261 267 268 268

xii CYCLI C LOADING OF SOILS

6.3 .2 Cri ticai-state framework 6.3.3 Stre s-strain and shea r strength rclationships

6.-t Mechanical propert ie of granular materia!~ 6.-1 . 1 lntroduction 6.4.2 Resilient train 6. -1.3 Pia tic strain 6.-t.-1 Examples of eta tic and plastic response of railroad ballast 6.4.5 ln fluence of grading, compaction and minerai type 6.4.6 Laboratory testi ng 6.-1.7 Field testing

6.5 Methods of analysis 6.5.1 Finite element 6.5 .2 Layered systems 6.5.3 Permanent defo rmatio n

6 .6 Applications to design 6.6. 1 Pavements 6.6.2 Rail track

References

7 Design of foundations and soil structures for seismic loading J. W. PAPPIN

7.1 Introduction Part A - Seismic loading 7.2 The nature of ei mie loading

7 .2.1 Earthquakes 7.2.2 Quantifying earthquake size and seismic loading 7.2.3 The nature of eismic loading experienced by strucrures

Part B- General principles in designing fo r earthquakes 7.3 lnput motions and structural response

7.3.1 The complexities of input mo tion and structural response 7.3.2 Response spectra 7.3.3 Choice of input motion

7.4 Soil properties for seismic design 7.4.1 Bulk density 7.4.2 Stiffness and materia! damping 7 .4.3 Strength 7.4.4 Degradation due to cyclic loading 7.4.5 Methods for assessing liquefaction potential

Part C - Specific design situations 7.5 Slopes and earth dams

7.5.1 Slope stabiliry during seismic loading 7.5.2 Earth dams

7.6 Building foundations 7.6.1 Pad foundations 7.6.2 Raft foundations 7.6.3 Piled foundations 7 .6.4 Liquefaction in the vicinity of building structure 7.6.5 Dynamic soil- tructure interacrions 7.6.6 Site variability

7.7 Retaining srructures 7. 7 . l Introduction 7.7.2 Earth pre sures 7. 7.3 Flui d pressures

7 .8 Lifelines 7.8. 1 The requirement for lifeline integrity during seismic events 7.8.2 Damage to lifelines

References

270 8 272 278 278 27 281 282 284 290 294 295 295 296 297 297 297 300 302

306

306 307 307 307 308 312 313 313 314 318 318 325 325 325 330 330 335

9 338 338 338 340 342 342 344 345 347 349 lO 358 358 358 359 361 361 361 362 363

CO TE TS XII I

Machine foundations 367 T. G . DAVIES

8. 1 lntroduction 367 8.2 Basic theory of dynamics 368

8.2.1 lnt roduction 368 8.2.2 Vibratory motion 368 8.2.3 Singlc degree of freedom system 369 8.2.-t Continuum elastodynamic 373 8.2.5 Tran ient motion 374

8.3 Shallow foundations 375 8.3.1 lntroduction 375 8.3.2 Historical survey 375 8.3.3 Foundation re ponse analysis 377 8.3.4 Foundation impedances 380 8.3.5 Experimental data 384

8.4 Deep foundations 385 8.4.1 lntroduction 385 8.4.2 Historical survey 386 8.4.3 Single piles 386 8.4.4 Pile groups 389 8.4.5 Experimental data 391

8.5 Design practice 392 8.5. 1 lntroduction 392 8.5.2 Design loads 393 8.5.3 Serviceability 394 8.5.4 Design practice 395 8.5.5 Post-construction tuning 396

8.6 Geotechnical parameters 396 8.6.1 lntroducrion 396 8.6.2 Shear modulus 397 8.6.3 Materia! damping ratio P 400 8.6.4 Poisson's ratio 402

8.7 Design examples 403 8.7.1 Shallow foundation design 403 8.7.2 Deep foundation design 405

Appendix 8.1 407 References 407

Effects of cyclic loading on the long-term settlements of structures 411 N. J. O"RIORDAN

9. 1 lntroduction 411 9.2 Structures founded on cohesionless soils 414 9.3 Structures founded on cohesive o ils 420 9.4 Cyclic loading of foundations piled through soft ground 428 References 430

Vibrational loading used in the construction process 434 D . A. GREENWOOD

10.1 lntroduction 434 10.1.1 Vibration as a means of installing subterranean structural elements 434 10.1.2 Soil compaction by vibration 434

10.2 Mechanism 438 10.2.1 Vibrating machines 438 10.2.2 Penetration by soil displacements 440 10.2.3 Deep compaction 442

xiv CYCLI C LOADI G OF SOl L

10.2A Horizontal surface layer compaction ~8 10.2.5 Effects of vibration frequency -152

10.3 Machine and process characteristics -156 10.3. 1 Pile-casing and sheet-pile dri,•er -156 10.3.2 Pipe drivers -157 10.3.3 Compaction machines -159 10.3.4 Comparison or deep vibrators and casing drivers ro r compaction 463 10.3.5 Surrace layer compaction 46-1

IOA The influence or vibrating plant on structures and people 467 10.4. 1 Threshold for soil settlement 470 10.4.2 Yibrations induced in structures 471 10.4.3 Soil tresses induced by vibrations 472 10.4.4 uisance to people 472

10.5 lnstrumentation for process contro! 473 References 474

Index 477