Dam Foundation Grouting

Revised and Expanded Edition

by

Kenneth D. Weaver

Retired Grouting Consultant

Dona Id A. Bruce

Geosystems L. P.

ASCE PIIESS

Contents

Preface ... ... ...................... . ....................... xvii

Acknowledgments ........................................ .. .. xix

Cbapter I . Introduction ..... .... .. ... ..... .... .... .. ..... .. .... . l

l. l ·rhe Basics ....... .. ....................................... l 1.2 A History or Grouting ....................................... 2

1.2.1 Origins in Europe ..................................... 2 1.2.2 The Early HislOT)' of Grouling in lhe Uniled Slates ............... 4 1.2.3 Laler HistOI)' of Grouting in l h e United Slates ............ ..... l l l .2.4 LatP 20th Centwy Arlvanees .............................. 14

1.3 Es ential Elcments or a Good Grouting Project ................... 15 1.4 Grouting as Exploration ..................................... 17 1.5 CompULer Applications ..................... ... . ... ......... 17

Cbapter 2. Geologie and Geohydrologic Considerations ............... 19

2. 1 ite Geology and Geohydrology Must Be nderstood ...... ........ 19 2.2 Si te l nvestigations for Grouting Program Design . ... ....... ....... 2 1

2.2.1 Regional Geologie Review ............. ............... ... 2 1 2.2.2 Photointe1jJretation . ... ................ .. .............. 2 1 2.2.3 Geologie MajJping . . .................................. 22 2.2.4 Geophysicn.l Surueys ....... . ..... ...... .......... . ..... 23 2.2.5 Direcl Subsmface Geologie lnvestigations .................... 23 2.2.6 Geohyrlmlogic Studies .. ................................ 26 2.2. ì Geologie luterprelation ...................... . ... .. ..... 28

2.3 Permeability Assessmem fo r Grouting Programs .. ....... .. . .... .. 28 2.4 Geologie Conditions Affecting Grouting Programs ................. 34

2.4.1 Sedimen/01)' Roek Foundations ............................ 34 2.4.2 Soluble Roeks ........................................ 41 2.4.3 Volranie ami Pyroclastie Rocks ............................ 4 7

vii

viii

2.-1.-1 2.4.5 2.4.6 2. -1. 7

CONTENTS

c:mwlic flllrl J\lt>/tl/IIUijJiuc Rnd<.\ ................. . . . ... . .. 5:3 "f"ì>tlonic !·ì>atu res . ... ... . ... ........... . . . . . ... . . . . . .. 57 Slrep ur Un~table .)'/ojJe.\ ... ...... ....... . ........ . . . . . .. 60 UnconsolirlaiNI Defwsils ... .. .. . .... .. .... . . . . . ....•. • .. 62

Chapter 3. Conceptual Design Considerations . . ........... ...... ... . 67

3. 1 Cenera i Consideration . .... .. ................. . . ...... . . . . . 67 3.2 Test Grouting ........... . . .................. . . . ...... .. . .. 67 3.3 Grout Curtain Dept.h ............................ . ..... . .... 69 3.4 Grout Curtain Length ........................... . . ......... 70 3.5 Crout Hole Spacing ............................. . ...... .... 72 3.6 C rout Hole O rientation .................... . . . . . .. . ......... 72 3.7 Single-Row Versus Multiple-Row Cunains .... . . . . .... . . . . ....... 73 3.8 Grou t Caps and CutofT Walls ... ....... .... ...... . ........ . . . . 74 3.9 Grout Galleries ............ ............... . . . .......... .... 78 3. 1 O Blanket Grouting and Consolidation Grouting ... . . . .............. 81 3.11 Design Standards ......................... . . . .......... . . .. 82

3. Jl. I Gfnerolìzetl GnidelinfS ................ . . . .............. 82 3.11.2 Quanlitalively Engineeretl G1'0ul CuTtriÌns .... . .... ........... 83

Chapter 4. Grouting Materials .. ....... ... ....................... 87

4 .1 Introduction and Classification . . . . . . . .. ....................... 87 4.2 Water .............. . . .... ..... .. ... . .... . ......... . ..... 88 4.3 Category l Materials: Particulate Grouts . . ................. ..... 90

4.3.1 Cements ............... . . . . . . ........ .............. 90 4.3.2 Pozzolans ..... .. ...... ..... .............. . .... . ... l 03 4.3.3 Clays .. ........ .... . . .... . . . ............. . .. . . . .. . IlO 4.3.4 lnut Fillers .................. ........... . . . . ....... 11 3 4.3.5 Chemical Admi.xlttres . . ........... ....... .. . ........... 115

4.4 Category 2 Materials: Colloidal Solutions ..... . ................. 126 4.5 Category 3 Materials: True Solutions ......................... . 130

4.5.1 AC1)•1ic Resins . .......... ....... ................... .. 130 4.5.2 Phenolic Resins .................. ............... .... 13 1 4.5.3 Aminoplastic ResirtS ............... ..... .............. 132 4.5.4 PolyU1·etlwne Resins ... . . . .............. . . ........ .... 133

4.6 Category 4 Materials: Miscellaneous ......... . . . . . ............. 133 4.6.1 Hot Mells (Bitumens) ............. . . . ..... . ........... 134 4.6.2 Polyesters ................................... ....... 135 4.6.3 Epoxies ...................... ............. ........ 135 4.6.4 Montan Wax ......... .................... .......... 135 4.6.5 Silicones ............ ........ ...................... 135 4.6.6 Silocsols ... . .................. . . ............. ..... 136 4. 6. 7 Precipilation Grottls .... . ... . . . . . . . ................... 136

4.7 Fina! Remarks ......... . ... . . . . . ... . . . ............... .. . . l 36

CONTENTS ix

Chapter 5. Basics of Particulate Grout Mix Design, Testing, and Performance . . ...................... . ........... . . 137

5.1 Basic l'ropcnies and Parameters ... .......................... 138 5. 1. 1 Rheology ........................................ .. 138 5.1.2 A Li/Ile l'vlore 011 Rheology .............................. 145 5.1 .3 BleNI (Selllenwnl or Sedime11latìon) .............. ......... 146 5. 1. 4 Pressure Filtra/io n . .. . . .............................. 148 5. 1.5 Woter-Rej;e/lent and !lntiwashout Clwracterìstics .. ... ... . ... .. 150 5.1 .6 Prevention r~f Particle Agglomeralion ...................... 15 1 5. 1. 7 H)•dmtion Contro/ ............................. .. .... 152 5.1.8 Prevenlimt ofFiller Segregalion ................... .... ... 152 5.1.9 Matrix Porosity ........ . ..... ....................... 152 5. 1.1 O Groin Size ........ . ... ............ ................. 153 5.1. Il Hardenìng . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154

5.2 T esting of Crouts ... .............. . . ................. .. ... 154 5.2.1 Co!tesion and Gelation ................................ 155 5.2.2 ApjJarent Viscosity ..... ............................... 157 5.2.3 Bleed or Sedimenlalion ... .... ... . . ........ ............ 158 5.2.4 Pressw·e Filtration . . . ........................ ........ 160 5.2.5 Washout Resistrmce . . . ............................... . 160 5.2.6 Filler Segregation ................ ... ... .. .......... .. 16 1 5.2. 7 Specific Gmvity .................................. ... 162 5.2.8 Sei Times .................. ................. ..... .. 162 5.2.9 Strength ............. ................ ............. 163 5.2.1 O Matrix Porosìty ........... ............... ........... 165 5.2.1 L ComfJalibility .. .. . ... ................. ........... . . . 165

5.3 Mix Design Considerations ................................. 166 5.3 .l WClle r: C eme n t Ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166 5.3.2 Neat Cement Grouts .............. .. . ......... ........ 166 5.3.3 Cla.y or Bentonite-Cemenl Orouts ......... .. .... . ......... 169 5.3.4 Grouts witlt Fillers and Pozzolaus ......................... 172 5.3.5 Grouls for Special ApjJlicalions . . .. ....................... 174 5.3.6 Grouts with Enhanced Penetrctbility ............... ....... . 176

5.4 Digest. ofTypical Multicomponent Formulations ................. 178

Chapter 6. Grout Injection P ressure .. ................ . ...... . .... 185

6.1 Controversia! Rules .... . . ....................... .......... 185 6.2 European Crouring Philosophy ..... ....... ... . .............. 185 6.3 Contemporal)' Ew-opean Crouting Theor)' ..................... 187 6.4 European and Other Foreign Grouting Practice .................. 189 6.5 Relevant 1l1e01)' from U .S. Practice ........................... 190 6.6 Relevant U .S. Practice ....... ...................... ... . .... 190 6. 7 Conclusions Regarding Injection Pressure ......... ............. 19 1

6. 7.1 Some Bases for Selection of lr~jection Pressm·es ........... ..... 19 l 6. 7.2 Special Considerations ........................... .... .. 192

x CONTENTS

Chapter 7. Miscellaoeous Factors Affecting Grouti ng Effectiveness ..... 193

7. l M<nerial ;md Mi x Pro perties Affecring Grout Penetration . . ........ 193 7. I .l Rheology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193 7. 1.2 StH'Cifir Gravity . . . . . . . . . . . ... . . . . . . ...... .. ........ 194 7.1.3 SPlllement (8/eed) . .. . . . . .. .. .... .. . . . ... . .. ... . ...... 194

7. 1.4 JJress11re Filtmlion .. . . . . • . .. . . ... .................... 194

7.1.5 Grain Size ............ . ... . . . ............. . . . . . . . . . 195 7.1.6 Water-Repel!tmt and Anti-Washout Characteristics ......... . . . . 195

7.2 Fracture C haracre risrics An:ecting Grout Peneu·ation ...... ........ 195 7.2.1 Fractu:re Aperture ........................... . ........ 195

7.2.2 Rou.ghness ....................... . ................. l 96 7.2.3 Hydraulic Routing ................................... 196 7.2.4 Tortuosity ... . ... . . . ............................ . .. 197 7.2.5 Po1·osity ........ . ... . .. ..................... ....... l 97 7.2. 6 Penneability ......... . . . ... ................ ......... 197

7.3 Procedura! Factors Affecting Grouting Effectiveness .. . . . .......... l 98 7.3.1 Drilling MethocLç ancl Procedures ........ . ................ 198 7.3.2 P.rotection of Holes ..... .............. ..... .......... . 199 7.3.3 G1·out Mixing P.rocedures ......... .. . ....... ...... ..... 200 7.3. 4 Choice of Orou.ting Mel h od ......... ............ . . ...... 200 7.3.5 Stage Refusa.l Criteria .......... ....................... 200 7.3.6 Closure Criteria ..................................... 202 7.3. 7 Baclifilling Method ... . ...................... ......... 203

7.4 Climatic Factors Aflècting Grouting Effectiveness ................. 203 7.4.1 Winte1· Grouting . .. . . ..... . .......................... 203 7.4.2 Hot-Weather Grouting ............ ......... ... .. ... ... 204

7.5 Design L'actors Affecting Grouting Effectiveness ... ... .... ....... . 206 7.5. 1 Grout Curla.ìn Depth ....... . ... .................... . . 206 7.5.2 Grout Curtain Lenglh .... ..... ... .............. ....... 207 7.5.3 G1·out CttTlain Widlh .. . .............. . ....... ........ 207 7.5.4 G1'0ut Hole SfJacing .............. ...... .............. 207 7.5.5 G1·out Hol.e Orientation . . . . ...... . . . . . ................. 208

7.6 Nebulous Factors Affecting Grouting Effectiveness ........... . . . .. 209 7.7 Factors AffectiJ1g Grout Curtain Durabili ty . ....... ......... .. . .. 210

7. 7. 1 Geochemical Environment ......................... . .... 21 O 7.7.2 G1'0ut Mix Design ......... .................... ...... 210 7. 7.3 H)•dmulic Gradient . ...... ............ . ........ ....... 211 7. 7. 4 Erodibili.J,y OT Solubi.lity of the Rock. Mass or Defect lnfillings ...... 212

Chapter 8. Drilling .... ... .... ... •.. ....•.. . .... . .•..•........ 213

8.1 Introduction .. ......... ........................ . ......... 2 13 8.2 Systems, Metl1ods, and Applicability ................ .... . . ... .. 2 14

8.2.1 Common Featu1·es . . . . ................................ 2 14

CONTENTS xi

8 .22 Hm k D111l111g . ...... . . ..... ................... . . . ... 2 1.:; 8. 2. ] Or•t•rburdPn Dnll111g ............ . .. . . ....... . .... .. ... 22.:;

!'U Drilling Equipment ............... . ........ . .... . . . ....... 2:~ l 8. J. l Drilling Rig.1 ......... . . .... ........................ 2:$1 8. 3.2 Fltt,lh PtonjJ.\ ....................................... 2;~2 8. J.3 Jllintlte~ .......................................... 23!3 tU . ..f Swjjòlding ...... . ... ............... ............... 234

8.3.5 Mobile Platjimn1 ........... ....... .................. 2:n ~H l'ltc Significance of Circulation T r pe and Applicatio n ............. 2:n 8.5 Borehole Deviation .............. ... ...................... 242

8.5. 1 ControLç ovu Devialion ....... ........ ................. 242 8.5.2 E>.mnpiP~ of Monitoml DPvinlion Dala ..................... 244 8.5.3 Measuremenl of Dl'virrtion .............................. 246

8.6 Rccording or Drilling Progress and Parameters .................. 255 8.6. 1 Basic CmtCI'/Jls ........... .. .................. . ...... 255 8.6.2 J\1/anua/ Measurnnenl WhìiP Drilling ...................... 257 8.6.) Jluto111aled Mensuremenl Wltile Drilling ................ . ... 257

8.7 Final Commem .......................................... 262

Chapter 9. Grouting Equipment ....... .... ... .. ... . ....... .. .... 263

9. 1 Grout Mixers .................. ........ .................. 263 9. 1. l Higlt-Speed, Higlt-Sitear Colloidol Mixers .... ....... ........ 263 9.1.2 Paddle Mixen ............ ....... ............... .. .. 266 9. / .J Other Tyjm of Mixm ........ ... ...................... 266

9.2 Crout Agitators .......................................... 268 9.3 Croul Pumps .................... .... .................... 274

9.3. 1 Progressive Cat~ily Pumps .............................. 274 9.3.2 Piston PumjJS ....................................... 275 9.3.3 P/unger PrwtfJS .. ......... ............... ..... ....... 276

9.4 Auxi liary Equipmenl ...................... .. .............. 276 9.4.1 Water Ml'ters ..................... . ............ ... .. 276 9.4.2 Flow Meters ....... ........ ............... .......... 277 9.4.} Waler Ta11k~ ........ .............. ......... ........ 278 9.4.4 BenloniiP Hydration Tanks ........ ................ .... . 278

9.5 Crottt Plants ....................... . . ........ ............ 278 9.5. 1 tt1Lional)' (Centra/) P/anls ............................. 280 9.5.2 i\Jodular (Containeriud) Plrmls ............. ........ ..... 281 9.5.3 Bog Plants ............... ........ ................. 282

9.6 Basic Equipment l'or Crout lt~jection ......... ................. 284 9.6. 1 Conventional Croul Heoders ......... ......... .......... 284 9.6.2 Pressare Gtwgl's ... . ..... . . . ....................... .. 286 9.6.3 Pressure and Floru Rrcorden ............................ 286 9.6.4 Packrrs ........ . .................................. 289

xii CONTENTS

9.6.5 .\ lenwd P1jH'' ..... ....... . . ............... . ..... . . .. ~90 9.6 .6 Multiple-Prukn Slen.•ed Pipe Sy1ft' lll ....... . ... . ........... 29~

9. 7 Automated Recording and ConLrol )'l>tCm!> . .......... . .... .... . 2!12 9. 7.1 RPccmling auri Afonitormg .~)'.111'111,, .. • •• . .....•. •. ... ..•••• ~92

9. 7. 2 Nnu Dt•vf'lopmrnts ... . ....... . . . . . ......... . .... ..... 29G 9.8 Up lifl Monitoring Device . . . . .... . .. . . . .... . ........... .. .. 300

9.8. / Geunal Consl(/emtio11s ........... . .................... :wo 9.8.2 SimjJle De'!lias ...................................... :~o l 9.8.) Recenl DnH.fopmenls in Displacemenl DeiPCl/011 ............... 302

Chapter l O. Preparation for Grouting . ........................... 305

l 0. 1 Generai Considerations ...................... . ............ ~W5 l 0.2 Excavation a nd haping ................... . ............... 305

l 0 .2. 1 Core Fouudati011 Excavation DejJlh ....... . . .. ............ 305 10.2.2 Fmmdaliou Sha.pìug ................... .. . . . ......... 30G

l 0.3 Geologie Mapping .... ......... .............. . ........... 306 l 0.4 Bedrock Surface Treatmem ..... ............... . ........... 308

10.4.1 Tre(llmenl ofjoints, Faults, ami Fractw·e Zones ............... 3 10 l O. 4.2 Contro/ of Springs and Seeps during Conslruclion ............. 3 12 10.4.3 Surface Coatings .................................... 3 12 l 0.4.4 Dental Concrete ......................... .. ......... 3 14 l O. 4.5 Regularizing Concrete ...................... ... ....... 3 14

l 0.5 Grout Caps an d CutoiT Walls ..... .......................... 3 14 l 0.6 Grout Galleries ......... ................ ................. 3 16 l O. 7 Access for Drilling, Crouting, and Inspection ................... 3 16 l 0.8 Work Area Proteccion ..................................... :3 16 l 0.9 Surveys ..... ........ .......... ............. ... ......... 3 17

l O. 9.1 Preliminary Suroeys ................................. 3 l 7 l 0.9.2 Supplemenla1)' Suroeys ............................... 3 18

l 0. 1 O Grout Nipples and Standpipes ... ................ ........... 3 18 l 0. 11 Arrangement of Equipment .......... ...................... 3 19

l 0. 11 .1 Crout Plauts an d Agi.talors ..................... ....... 3 19 1 O. l 1.2 Headers and Pressure and Flow Reco·rders ................. 3 19

Cbapter 11. Basic Procedures for Bedrock Grouting ................. 32 1

l 1.1 Evolulion of Bedrock Crouting Procedure · ..................... 32 1 l 1.2 Pauem and Sequence ...................................... 322

11.2.1 Blanket Crouting .................................... 322 l 1.2.2 Multiple-Row Curtains ................................ 323 11.2.3 Split-SfJacing Sequences .. .................. , ... , ...... 32~3

l 1.3 Bedrock Drilling Proceclures ...... .......... ...... .......... 325 l 1.4 Washing Procedures .................. ............. ........ 328

11 . 4 .l Special Washing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2 8 11 .4.2 Pressure Washing .................................... 328

CONTENTS xiii

l l..i \\'atc:r-Prc tu e l c~t i ng ............................... . ..... 3:W 11.5.1 Ob.Jertit•l'' .................... . .................... :no 11 . 5.2 Roulim• ll'a ter- Pre.~ \ltrl' T1'.1ls .... . . . . ............. . ...... :~32 11 .5. 'J MultijJII'-Stage Waler-Pressure Tests . ..... .... . .... ..... ... :33:~

1 J.( i lkdrock GroUI ing PrO<:cdurcs . ... . ... . ........ . ... . ..... .. . . 33:) 1 /.tU GenPml PmrNIIlrt'.\ . .. .. . . .......... • . . .............. . 333 11 .6.2 Parker Sealing Promlure . . .......... . ... . .......... ... 3~7 1 1.6.3 Gmul t\liting Proredure.1 ........ . ... . .............. ... 3:36 1 1.6.4 election ofGrouf lnjerlion Pre.çsures ................... . . . 337 1 /.6.5 Gr-oul h yec/ton Procedure,, . . .. .. .. .... . .... .... .... . .. . 34 1

1/.6.6 Treatmml of SjJPrirtl Problrms ........................... 353 11 .6. 7 Groul Ho/e Bacltjìlli11g ............................. . .. 354

1 1. 7 Protection or Grout Holes . ................ . ...... . ... . .. . . . 354 11.8 oil and Ernbankment Grouting Methods ............. .. . .... . . 355

11.8 . .1 Permeation Crouting .. . . . . . . . ................. .. . . .. . 355 11.8.2 Compaction Crouting .... . ............................ 355 11.8.3 Hydrofracture Cronting ................................ 356 11.8.4 j et Crouling ............ ............................ 356 /1 .8.5 DeejJ Mixiug Method (DMM) ........................... 356

Chapter 12. Supervision and Inspection . .. ...... .. . ... .. .. . .. . .... 359

12.1 Overview ...................... . .................... . . .. 359 12.2 Supervision ......................................... .... 360 l 2.3 l nspection .................... .... ............. . ........ 362

12.3. 1 1nspection of Drilli11g Ojmntions ................ ... . . .... 363 12.3.2 1nspection of Crouting Opemtions ................... . .... 365

12.4 Saf'ety Consideration ...................................... 367 12.5 Dutie of Data Coordinator ................................. 368 12.6 Office Facilities for Grouting Operations ....................... 369 12.7 Field Laboratory Faci lities ........ . ......................... 370

Chapter 13. Records . . . .... .... . ... . . ........ . .. ... .. . . .. ... .. 371

13. 1 Generai Considerations ........ . . .... ................. . . . .. 37 1 13.2 Field Records ............................................ 372

13.2.1 Crout Ho/e Drilling Logs .......... . .......... . ........ 372 13.2.3 Pressure Testing and Crouting Logs ....................... 374 13.2.4 Daily Grouting Rl'jJorls ................................ 375 13.2.5 Fie/d Tesling RejJorls ........ .. ....................... 375

13.3 O ffice Records .................. . . . ...................... 376 13.3.1 Progt·ess Records ........... ... ................. . .... 376 .13.3.2 Data Tabulations ......... .. . .................. .... .. 376 13.3.3 Pian Drawings ........................ . ....... ... .. . 376 13.3.4 Profile Drawings ...... . .. ... . . ................... . .. 377 .13.3.5 Olher Record~ ...................................... 378

13.4 Progre s Reports ......................................... 378

xiv CONTENTS

Chapter 14. Quality Assuran ce, Q uality Contro!, and Verification ...... 381

I..J. l The Re,·iew Proce ........ . ..... . . . . • . •.• ................ ~~R l 14.2 C:lo ·ure CriLeria . .................. ................... . ... :~82

/4.2. 1 Permmbility Crileria ......... . . ....................... 382 14.2.2 Croul ·.rai!P. Crilnia ......... ... . . . . . . ............. .. . :384 J..I. 2.J Geologie Criferirt ........... . ... . . . .................. :.S8Cì l 4.2.4 ObsPmalional C1~/eria ......... . ... . • .................. :387

14.3 SLatistica l Evaluation Procedure · .. . .......................... 387 14.3.1 Red11clion Ratios ......... . ....... . ................. . 387 14.3.2 Mean llalue Bar CrafJhs . . . . . . . . . . . . . . . . . . . . . . . ....... 389 14.3.3 Frequenry Distribution Hislogroms ...... .... . . . ....... . . .. 389 1-1.3. 4 Summaliou Cu111eS ............ . ................... . . . 389 /4.3 .5 Penneabilily Profiles . . . . ... . . . . . ................... ... 390

14.4 Detailed Evaluation ........ . .............................. 39 J 14.5 Verilication Holes ..... ........................... . . . .. . .. . 393 14.6 Quali Ly Contro) Testi.ng of Grouts .......... ............ ...... 394 14.7 The Fi na) TesL ..... .................. .......... .......... 395

Chapter 15. Some Considerations for Remedial Grouting ....... . ..... 397

15.1 Outlook for Future Remedial eeds ....... . ... . .... . ... . .. . . . . 397 15.2 A Problem Appea rs ........... . . . . . ....................... 398 15.3 The Search for Causative Factors .................. . ... ....... 399

15.3. 1 Geologie Factors .. . ........................ . ....... .. 399 15.].2 Dissolution of Crou/ CuTlain ................ . ........... 40 l l 5.3 .3 i'n.af;projn"iale Grouting Materi.als cnul Fonnulations ....... ..... 40 l 15.3.4 Design Faclors .......... ........ .................... 402 15.3.5 1nafJprojniale Drilling Procerlures ............... . ........ 404 15.3.6 lnadequate CTouting EquifJ/nenl ............. . . . . . ........ 405 l 5.3. 7 Arlvrn-se Oimatic Conditions .. . . .. ........ . . . . . ... ..... .. 406 15.3.8 fnadequate Clostm ~f Cu·rtain .......... . ... . ............ 406 15.3.9 Jrw.dequate Injection Presmre ............................ 407 15.3.1 O lnadequate Quolily Assum:nce and llerification Procedm·es .. ..... 407 l 5.3.11 La.ck of Cormection lo the Strttclnre ........... ............ 408 15.3.12 Failure ofCalculaterl Risll .............................. 408 15.3.13 Economie FaclOI"S ................ . ...... . . . .......... 408

15.4 Some Examples of Causative Factors ..... . . . . ................ . 409 15.5 Basic Considerations [or Remed ial Grouting .......... . ......... 411 15.6 Faetors Impeding Remedial Grouting . ........................ 4 12 15.7 Basic Principles for Remed ial Grouting ........................ 4 13

l 5. 7. 1 Reduce the Reseruoir Head if Feasible ..... .......... ....... 4 14 15. 7.2 Selecl AjrjJTojn·iate Grouting MateriaLs ........ ........... . . . 4 J 4 15. 7.3 lntersectthe Voids cmrl Othe1· Openings ............. ........ 4 15 15. 7. 4 Use Correcl ancl AfJprojniate Crout-Delivel)' Systems ............ 4 16

CONTENTS xv

/'5.7.5 Monitor tlu ln;ntwn Data ............................. 11 6 15. 7.6 JHonilor 'erpoge. Dm ili\. Pinometen, and li' PII' .............. ..J 17 15. 7. 7 J\fodif)• the Pmgram a' AjJjJroj>riale ....... ................. ·11 7 15. 7.8 Jlerif)· l hl' H.e,\u/1.1 of t/11' CompiPled Remedwl Jllorh ............. ·Il 7

15.8 Remedial Crouting Oplions ... ........ ............... .... . . 4 17 15.8. 1 Targfted SujJJJinnenlnl)' Crouting ............ ...... ...... 4 17 / 5.8.2 Curtain Regrouli11g ........ ...... .............. .. .... 4 18 15.8.3 NP·w UjJSII'Pf/111 Curtoiu ...... ....... ................... 41 8 / 5.8.4 Parlial Demolition tllld Reconslmctùm of the Dtllll ........ ..... 419 l 5.8 .. 5 lllustmlive t ,/1.11' lli.110ries ............ ........ ........ .. 4 19

15.9 ome Considerations fo r Bici Procuremem and Contract Admin istration . .......................................... 427

Chapter 16. Specifications and Contracts . . .... .... ......... .... ... 429

16. 1 Cenerai and Historical Perspective . ..... . .. ........ ... ........ 429 16.2 Type of Specifications a nel Contracts .... .................. . .. 43 1 16.3 Items T o Be Addressed in Specifications ....................... 433 16.4 T he Qua1ification and Prequalification of Biclclers ................ 437 16.5 T he eed for f lexibi1ity and a Partnering Menta1ity ....... .. . .... 438 16.6 The Advisability of I nclependent T echnical Review ......... ...... 4 39

References ....... ... ........... . .......... ...... ......... .. 44 l

Index .. ........ .......... ..... .. .. ... ......... ... .... ... .. 465

About the Authors ..... .. .... ... ........... ... ........... ... .. 473