SOIL MECHANICS: Principles and Practice. Graham Barnes THIRD EDITION

Transcription

1 SOIL MECHANICS: Principles and Practice THIRD EDITION Graham Barnes

2 Contents Preface List of symbols Note on units List of case studies 1 Soil formation and nature Soil formation Man-made soils Contaminated and polluted soils Naturally occurring soils In situ soils - weathered rocks In situ soils -peat Water-borne soils Glacial deposits Wind-blown soils Soil particles Nature of particles Clay minerals Soil structure Cohesive soils Granular soils 2 Soil description and classification Soil description Soil categories Made ground Organic soils Volcanic soil Particle size fractions - fundamental basis Very coarse soil Coarse soil Fines Composite soils xii xiv xix XX Fine soil Mass structure Degree of weathering Geological origin Soil classification Particle density Particle shape Particle size distribution Grading characteristics Density Density Index Moisture content or water content Atterberg limits Activity Index Shrinkage limit Soil model Worked examples Exercises 3 Permeability and seepage Permeability Groundwater Flow problems Flow into excavations Flow around cofferdams Dewatering Flow through earth structures Stability problems - 'running sand' Boiling or heaving in cofferdams Piping Heaving beneath a clay layer Uplift pressures Soil voids Pressure and head

3 vi Contents Darcy's law 51 Effect of temperature 52 Empirical correlations for k 52 Layered soils 54 Laboratory test - constant head permeameter 55 Laboratory test - falling head permeameter 56 Laboratory test - hydraulic cell - vertical permeability 57 Laboratory test -hydraulic cell - horizontal permeability 58 Laboratory test - triaxial cell - vertical permeability 58 Borehole tests - open borehole 58 Borehole tests - packer tests 61 Borehole tests - piezometers 62 Pumping tests 63 Seepage 63 Seepage theory 63 Flow nets 66 Flow net construction 67 Seepage quantities 69 Total head, elevation head and pressure head 70 Pore pressure and uplift pressure 71 Failure by uplift (buoyancy) 71 Seepage force 72 Quick condition, boiling and internal erosion 72 Critical hydraulic gradient 73 Failure by internal erosion 73 Failure by heave - sheet piling 73 Failure by piping 74 Seepage through earth dams 74 Seepage through flood banks, levees 74 Soil filters Case studies 79 Worked examples 83 Exercises 94 4 Effective stress and pore pressure Total stress 97 Pore pressure below the water table 97 Effective stress 98 Effective stress in the ground 98 Stress history 98 a' Normally consolidated clay 98 Overconsolidated clay 101 Desiccated crust 103 Present state of stress in the ground 103 Mohr's circle of stress 104 In situ horizontal and vertical stresses 104 Changes in stress due to engineering structures 108 Pore pressure parameters - theory 110 Pore pressure parameters A and B 111 Capillary rise above the water table 112 Effective stresses above the water table 114 Desiccation of clay soils 115 Suctions 116 Frost action in soils 118 Frost heave test 120 Permafrost 121 Ground freezing Case study 123 Worked examples 125 Exercises Contact pressure and stress distribution Contact pressure 132 Contact pressure - uniform loading 132 Contact pressure - point loading 133 Stress distribution 134 Stresses beneath point load and line load 134 Assumptions 134 Stresses beneath uniformly loaded areas 136 Bulbs of pressure 137 Stresses beneath a flexible rectangle 137 Principle of superposition 137 Stresses beneath flexible area of any shape 137 Stresses beneath a flexible rectangle - finite soil thickness 137 Stresses beneath a rigid rectangle 139 Embankment loading Worked examples 144 Exercises 149

4 Contents vii 6 Compressibility and consolidation 150 Axial symmehy 192 Plane strain KO condition Normal and shear strains Compressibility Mohr circle of strain Void ratio/effective stress plot Volumetric strains Reloading curves Shear strength Preconsolidation pressure opt and Effect of strain overconsolidated ratio OCR Idealised stress-strain relationships Casagrande method for opt Yield and plasticity Effect of sampling disturbance Flow rule and normality In situ curve for normally consolidated clay Failure criterion In situ curve for overconsolidated clay Failure of soil in the ground Effect of load increments Stress paths Effect of duration of load Effects of drainage Effect of secondary compressions Test procedures Isotropic compression Shear strength of sand Anisotropic compression Stress-strain behaviour Consolidation Shear box test Terzaghi theory of one-dimensional Effect of packing and particle nature consolidation Constant volume condition Solution of the consolidation equation Effect of density Isochrones Shear strength of clay Average degree of consolidation Effect of sampling Oedometer test Undrained cohesion, c, Coefficient of consolidation, c, - root time Strength index tests method Strength tests Coefficient of consolidation, c, - log time Laboratory vane test method Fall cone test In situ c, values Unconfined compression test Rowe consolidation cell Field vane test Two- and three-dimensional consolidation Triaxial test Correction for construction period Triaxial unconsolidated undrained (UU) test Precompression by surcharging Multi-stage (W) test Radial consolidation for vertical drains Effect of clay content and mineralogy Partially saturated clays Case studies Fissured clays Worked examples Variation with depth Exercises 7 Shear strength Stresses and strains in soils 191 Representation of stresses 191 Pole 191 Principal stresses 191 Frictional characteristics Test procedures 221 Triaxial consolidated undrained (CU) test 222 Triaxialrconsolidated drained (CD) test 224 Critical state theory 224 Parameters 225 State boundary surface 225 Isotropic normal consolidation line (ICL) 225 KO normal consolidation line (KO CL) 227 Critical state line (CSL) 227

5 viii Contents Roscoe surface Tension cut-off Hvorslev surface The elastic wall Real soils Residual strength Case study Worked examples Exercises 8 Geotechnical Eurocodes Relevant Eurocodes Personnel Geotechnical Design Report Geotechnical Risk Durability Geometrical data Limit states Verification of limit states Design by prescriptive measures Design by experimental models and load tests Observational method Design by calculation Models and model factors Actions Design situations and values of actions Characteristic and representative values of actions Design values of actions Effects of actions Ed Design resistances Design approach and partial factors Characteristic values of geotechnical parameters 9 Shallow foundations - stability 255 Shallow foundations Definition Spread foundations Types of foundation Depth of foundations r~' Foundation design Design requirements Traditional approach compared with the Eurocodes Bearing resistance Modes of failure Bearing capacity and bearing resistance Shape factors Depth factors Base inclination factors Bearing resistance - overturning Eccentric loading Inclined loading Different soil strength cases Effect of water table Net ultimate bearing capacity Effect of compressibility of soil Sliding Allowable bearing pressure of sand Settlement limit Allowable bearing pressure Corrected SPT4N values Case studies Worked examples Exercises 10 Shallow foundations - settlements Are settlement calculations required? Immediate settlement General method Principle of superposition Principle of layering Rigidity correction Depth correction Average settlement Modulus increasing with depth Effect of local yielding Estimation of undrained modulus E, Consolidation settlement General Compression index C, method Oedometer modulus Eoed or mv method

6 Contents ix Total settlement Skempton-Bjermm method Elastic drained method Estimation of drained modulus E' Proportion of immediate to total settlement Secondary compression General method Estimation of C, or E, values Sands Methods of estimating settlements Schmertmann's method Burland and Burbridge's method Permissible settlements Definitions of ground and foundation movement Criteria for movements Routine settlement limits Case studies Worked examples Exercises 11 Pile foundations 326 Pile foundations Types of pile Loading conditions Uncertainty of design calculation methods Limit states Pile load tests Ultimate compressive resistance from static load tests Ultimate compressive resistance from ground test results Ultimate compressive resistance from other methods Weight of pile Bored piles in clay End bearing resistance qb Adhesion c, Driven piles in clay End bearing resistance qb Adhesion c, - installation effects Adhesion c, - values Effective stress approach for adhesion Driven piles in sand Effects of installation End bearing resistance qb Critical depth Skin friction& Bored piles in sand Mobilisation of base and shaft loads Downdrag (negative skin friction) Causes of downdrag Determination of downdrag Pile groups Stiffness of pile cap and structure Pile spacing Stressed zone Load variation Efficiency Ultimate capacity Settlement ratio Settlement of pile groups Case studies Worked examples Exercises Lateral earth pressures and 326 retaining structures 360 Lateral earth pressures Effect of horizontal movemint Effect of wall flexibility and propping Effect of wall friction Coulomb theory - active force Coulomb theory - passive force Limitations of the Coulomb theory Earth pressure coefficients Effect of cohesion intercept c' Minimum equivalent fluid pressure Effect of water table - gravity walls Effect of water table - embedded walls Undrained conditions Earth pressures - undrained condition Tension cracks Uniform surcharge Line loads and point loads Earth pressures due to compaction

7 X Contents Retaining structures Basement walls Bridge abutments Gabions and cribwork Design of gravity walls. Serviceability limit states Ultimate limit states Loss of overall stability Overturning or rotational failure Bearing pressure under the toe Bearing capacity Sliding Failure of structural elements Design of embedded walls Cantilever embedded walls - general Cantilever embedded walls - design Single anchor or propped embedded walls - general Single anchor or propped embedded walls - design Design methods Gross pressure method Net available passive resistance method Factor on strength method BS8002 method Anchorages for embedded walls Strutted excavations and cofferdams Strut loads Base stability of excavations Base stability - shallow excavations Base stability - deep excavations Reinforced soil Reinforced soil walls - construction Effects of reinforcement Reinforced soil walls - design External stability Internal stability - general Tensile rupture Pull-out resistance or adherence Internal stability - tie-back wedge method Coherent gravity method Case studies Worked examples Exercises a" 13 Slope stability Natural and artificial slopes Types of mass movement Natural slopes Artificial slopes or earthworks Short-term and long-term conditions Methods of analysis Plane translational slide - general Plane translational slide - Eurocode approach Plane translational slide - special cases Stability of vertical cuts Circular arc analysis - general Circular arc analysis - undrained condition = 0 analysis Tension crack Undrained analysis stability charts - Taylor's method Effective stress analysis Effective stress analysis - method of slices h Bishop simplified method Bishop simplified method - limit state approach Pore pressure ratio ru Stability coefficients - ru method Stability coefficients - water table method Submerged slopes Rapid drawdown Non-circular slip surfaces Wedge method - single plane Wedge method - multi-plane Factors affecting stability and slope design Case studies Worked examples Exercises 14 Earthworks and soil compaction 462 Earthworks Construction plant

8 Contents xi Purpose and types of materials Material requirements Suitability of fill material Suitability of granular soils Suitability of cohesive soils Moisture condition test Efficiency of earthmoving Material problems Softening Bulking Soil compaction Factors affecting compaction Field compaction Compaction plant Specification of compaction Control of compaction in the field Laboratory compaction Light compaction test Heavy compaction Vibrating hammer Air voids lines Correction for oversize particles California Bearing Ratio (CBR) test Addition of lime Cement stabilisation Case study Worked examples Exercises 15 Site investigation 499 Site investigation Relationshp with geotechnical design Stages of investigation Desk study Site inspection Ground investigation Extent of the ground investigation Depth of exploration Choice of method of investigation Methods of ground investigation Undisturbed sampling - sampling quality Types of samples Methods of in situ testing Dilatometer tests Groundwater observations Investigation of contaminated land Ground investigation report Presentation of geotechnical information Factual report Geotechnical evaluation Answers to Exercises Glossary References Index

9 A parameter, see pressure, parameters abutments, bridge, 377 actions, 244,246, 247,248,249, 250,251, ,341,352, 357 active pressure, see earth pressure activity, activity index, 35,36,44, 234,410 adhesion, 207,266,272,330,332, 333, 334,335,336,354,367, 369,373,405,406 aeolian soils, 6 air entry value, 113, 117 air voids, 36-38, 113, 115,213 content, 38,45,479,493,494, 496 lines, 478,484,492,493 allowable bearing pressure, 264, 381 sand, 272 et seq, 284,287 allowable settlements, see foundations anchors, 341,377,384, 386 angle of shearing resistance clay, 199,201,206,217,218,221, 222,224,231,232,238,267, 268,270,271 sand, 199,201,206,207,208, 209,210,211,236,267,268, 270,271, 272, 336,337, 338, 339,340,361 angular strain, 308, 323 anisotropic soil, 63, 68,70, 83, 91, 97,106, 110,156,157,213,301 aquicludes, 47, 83 aquifers, 48, 176, 179, 517 arching, 80, 81,364 area ratio, 5 10 artesian, 47,48, 82, 83, 88, 123, 124 at rest, see earth pressure Atterberg limits, 22,31,32, see also liquid limit and plastic limit augering, 503,504, , see also hand augering axi-symmetric condition, 104, 110, 192,193,205,210,214 B parameter, see pressure, parameters backpressure, 57,58, 127, 168,215, 223,237,239 band drains, 173, base-exchange, see cation-exchange basements, 202,204,347,377,378 case study, Nicholl Highway, case study, Tokyo, Japan, top-down method, , bearing capacity, see also allowable bearing pressure; piles; retaining structures base inclination factors, 267,268 depth factors, 267,268 eccentric loading, 268,269, effect of compressibility, 271, 316 effect of water table, 263,271,274 factor of safety, 264 factors, 266,267 inclined loading, 266,269,270, limit state design, see limit state design modes of failure, 264,265, 266, 276,277 net ultimate, 271, punching shear, 265 safe, 264 shape factors, 267,268 stren,a cases, 270,271 theory, ,276 vertical load only, , 277, bedding, 21 bentonite, see montmorillonite boiling, 49,72,73, 83, 91 %orehole permeability test, see permeability borehole record, 82,521,523 boulder clay, 123 boulders, 1,4, 6, 16, 17,53,504 description, 17, 18 brucite, 7, 8 bulbs of pressure, 137 bulk density, see density bulk modulus, 194 bulking, ,490,491 cable percussion boring, see ground investigation, methods capillaries, 5 1, 112, 113 capillary break, 129 capillary rise, 99, 112, 113, 114, 129, 262,427 Categories, geotechnical, , 288,443 cation-exchange, 9,102,155,235 CBR, 466, cement stabilisation, 465,486,487 characteristic values, 249,250,252, see also limit state design

10 Index 541 foundations, 279,280,281,282 material properties, 249,250, 25 1 negative skin friction, 342,356, 357 pile load, 329, 330,331,352,353, 354,355,356 sliding, 272 slope stability, 425,426,427,428, 430,432,433,434,435,438, 441,442,443,450,455,456 statistical approach, 250,253 water table, 72,73, 82, 88, 89, 90, 92,93,402,426,450,517 weight density, 426,427,495 Charity Hospital, USA, case study, 145,349 chlorite, 8 classification, 14 et seq, 15, 17,23, 44 clay, see also consolidation; shear streno&, bearing capacity; earthworks; walls; slope stability classification, 20,22,34 content, 32,33,35,218,232,234, 410 description, 17, 19,20,22,23 drainage conditions, see drainage fissured, see fissures minerals, 7, 8,9, 10,218 partially saturated, 218,223,236 sensitivity, 5, 6, 179,213,214, 234,298, 303,418,445,446, see also moisture sensitivity settlements, see settlements size, 8, 15, 27,465 softening, soil, 8 stiffness, 132, 133 strength, see strength coarse soil, 14, 16, 17, 18 cobbles, 5, 6, 16, 17,53,504 description, 18 coefficient of compressibility, 117, 118, 163, 164, 167, 169, 173, 180, 181, 182,297,298 consolidation, 158, 159, 163, 164, 165, 166, 167, 169, 170, 173, 174,175,182, 183 consolidation, in situ, 166, 167, 172 curvature, 27,28,40,465 earth pressure, see earth pressure permeability, 51,52,54-61, 158, 167, 173, 182, 184 secondary compression> 163, 179, 302,303 cofferdams, see also sheet piling base stability, boiling, see boiling effect of flexibility and propping, 364 flow around, 48 flow net, 68, 89 piping, 49,73,74, 89 strutted excavations, , , cohesion, undrained, see strength cohesion intercept, see strength, effective stress or drained, clay colour, terms, 18, 19,21 compaction air voids lines, 478,479,484,492, 493 compactive effort, 465,474,475, 476,479,481,482 correction for stone content, see oversize particles density, 467,474,475,478,479, 483,484,491,492,494,495 earth pressures due to, factors affecting, field, 124,465,476,478,479, 480,481,493 laboratory, 465,474,475,478, 482,483,491,492 layer thickness, 479,480 moisture content, 43,5 1,465,467, 468,474,478,479,480,483, 488,491,492,493,484,495 plant, 465,476477,479,480,481 soil type, 465,476 specification, 465,467,478,479 composite soils, 18, 19,27 compressibility, 150 et seq coefficient of, 117, 158, 163, 164, 165,169,173,180,297,298 disturbance, 153 in situ curves, 153, 154 index, 306 load duration, 154,155 load increments, 154 reloading curves, 151, 152, 155, 156 secondary compression, 155, 156 void ratio-pressure plot, 99, 101, 102, 109, 150, 151, 152, 153, 154, 155, 156, 157, 176,296, 320 compression anisotropic, 110,206 isotropic, 110, 156,207,225,226, 227 triaxial, 110,207 compression index, 163, 164, 179, 180,181,219, cone penetrometer, 30,207,304, 305, 321, 330,338,503, consistency, 20, 32 consistency index, 9, 13,31,32, 35, 44 consolidation analogy, 109, 157 around piles, 341, 342 cell, 56,57 coefficient of, 158, 159, 163, 164, 165, 166, 167, 169, 173, 174, 175 correction for construction period, , ,187 curve-fitting, , 182, 183 degree of, 159, 160, 161, 162, 165, 166, 172, 173, 174, 184, 185, 186,187 deposition, 99, 100, 101, 102 in situ curve, in triaxial test, 127,223 isochrones, 159, 160 oedometer test, 157, one-dimensional theory, , 160

11 542 Index consolidation (continued) primary, ,164,165,166 radial, 59,168, , settlement, see settlement two- and three-dimensional, 169, 488 construction pore pressures, see pressure contact pressure, 132 et seq contaminated soils, 2, 15 contiguous bored pile walls, see walls creep, see secondary compression crib wall, see walls critical depth, ,356 critical hydraulic gradient, 73,91 critical state, theory, 156, 157,224 et seq cuttings, 202,203,204,420,421, 422, see also slope stability damage to buildings, see settlements, permissible deflection ratio, 308,309,310, 323 deflection rule, 68,69 delayed compression, 103, 154, 155, 156,179 density, 12, 13, 28, 29, 41 bulk, 28, 37, 38,40,41,98, 100, 163 dry, 28,38,40,41,163,467 effect of, 210 in situ, 29,42 index, 9, 13, 18,20,29, 30,42, 209,210,211,271 maximum, 12,27,29,42 minimum, 12,29,42 particle, see particle density relative, see density, index weight, see weight density depth correction, 191,299,300,304, 347 factors, 267,268 of exploration, 276, 349 of foundations, see foundations description, 14 et seq desiccated crust, 103, l$4,276 desiccation, 102, 115, 116 Design Approaches, ,435,450, 451,455,456 allowable bearing pressure, 284 by calculation, 248 by experimental models and load tests, 247 by prescriptive measures, 247 by tests, 247 foundations, 263 et seq, , 287,288 observational method, 247, , Reports, geotechnical, , 500,520 site investigation, situations, 248 design values actions, 247,249,250 earth pressures, 249 foundations, 279,280, 281,282 geometrical data, 246, 249 geotechnical parameters, 246, 249, 252 ground resistance, 246 modulus, 289 piles, 329,330, 331,340,341, 352,353,354 reinforced soil, 391,392,393, 394,395 resistance, 247, 249, 250 serviceability criterion, 247 sliding, , slope stability, 425,426,427,428, 430,432,433,435,438,441, 442,443,450,455,456 uplift, 72,73 walls, 385,386, walls, surcharge, 373,374 water table, 88, 89,90, 92,93, 249,370,371,402,405 desk study, 501,519,520,522 dewatering, 48,49, 83, 171 diaphragm walls, see walls differential settlement, 308,309, 310,349,392 dilatancy, 19, 196, 197,207, 208, 209,210,211,213,336 discontinuities, 21,22 dispersed structure, 11 disturbance, 153, 176,211,224, 294, 508 downdrag, see piles; negative skin friction drainage blankets, 49, 124,464,488,489 drained condition, 109,203,204, 205,206,211,215,221,224 gravity, 295,371 in hydraulic cell, 58,59 path, 157,159,160,161,165, 166, 167,168,169,172 stress change, due to, 109,204 undrained condition, 20, , 211,213,215,221 drained, see drainage drains band, 173, horizontal, sand, 172 vertical, , drawdown, 204,424 drumlins, 4 dunes, 6 durability, 245 earth dams, see also slope stability; earthworks construction pore pressures, 123, 124,204 flow through, 49,74,75 stability, 74,76,204,421,424, 443,464 earth pressure active, 106,361,363,367,370, 372,383,384,385, at rest, 57, 104, 105, 106, 107, 108, 110, 117, 126, 127, 156, 157, 192, 193,200,201,202,207, 226,227,336,337, 339,340, ,363,395,396,516 coefficients, 361, 362, 365, 366, 367,368, 369,372, 373, 374, 375,391,402

12 Index 543 due to compaction, due to surface loads, 373, 374, 375,405,406 effect of cohesion intercept, 369, 370,405,406 effect of flexibility and propping, 364,378 effect of movement, effect of wall friction, , 374,405,406 effect of water table, 366,370, 404,405 minimum equivalent fluid pressure, 369 passive, 106, 362, 363, 366,370, 380,383, 384,385, 407,408 undrained, 372,373 earthworks acceptability of cohesive soils, 466,468,469,471,485,488 acceptability of fill, 123,465,466 acceptability of granular soils, 466,467 bulking, ,490,491 compactability, 467 compaction plant, 465,467, ,479,480,481 construction plant, 462,463,468, 469,471,473,488 efficiency, 462,467,469,471 material requirements, 460,463, 464,465 MCV, 467,469471,486,490 softening, eccentric loading, see bearing capacity; walls effective area, 268,269,270,381,391,394 size, 27,40, 52, 53, 54, 84, 114 elevation head, see pressure embankments, see also earth dams; slope stability; earthworks; stress distribution stability, 202,204,421,423,488 engineered fill, 1, 14,253 equipotential lines, 65, 66, 67,68, 70,71 equivalent fluid pressure, minimum, 369 moisture content, 31,43 raft, 347 erosion, 3,50, 83, 101, 102, 125, 262,277,278,307 internal, 72,73 eustacy, 177 excavations, see also cuttings flow into, 48, 83 stability, 49, 83, 88,388, 389,420 strutted, see cofferdams vertical cuts, ,451 expansive soils, 116, 117, 118 factor of safety, 249,250,264,294, 301,319,380,381,382,384, 385,389 factors, partial, see limit state design failure modes, 190, 200, 202, 246, 247,250,262,264,266,276, 277,327,419,420,421 fall cone test, 211,212, see also liquid limit falling head permeability test, 56,57, 84,86 fill, see earthworks, acceptability of fill; made ground filter paper method, 117 filters, 49,74, 76,77 fie soil, 14, 17, 18, 19,20,21 fines, 17, 18,27,31,77,465,466 fissures, 5,21,22,23, 119, 167,203, 213,214,217, ,332, 334,372,428 flexible foundation, 132, 133, 134, 136, 137, 138, 139, 140, 146, 169,289,323 flocculated structure, 11 flood bank, 49,74,75, 83 flow lines, 48,49, 65, 66, 67,68, 70 flow nets, 66, 67,68,69,70,74 flow rule and normality, 198, 199 flow slides, 421 flows, 48 fluvio-glacial drift, 4 foundations, see also bearing capacity; settlements; stress distribution allowable settlement, 264,272 depth, 136,255,257,259,260, 261,264,291 effect of tree roots, see trees, effects of pad, 257,258 pier and beam, 256 raft, 132, 133, 137, 139, 140, 145, 255,258,277,290,309, 315, 323,342 spread, 132, 137, 141,255,276, 288,309 stiffness, 132, 133, 134, 139, 141, 145,247,255,258,291, 315, 316,323,329,331,342 strip, 136,137,140, freezing index, 118, 119 freezinglthawing, 5 frost action, 118, 121,262 frost heave test, 120 frost susceptibility, 118, 119, 120, 262 gabion walls, see walls geological origin, 20,21,22 geometrical data, ,279,280, 281,373,374 gibbsite, 7, 8 glacial deposits, 4,22,23,217,222, 234,332,334,445,448,488 gleying: 4 grading, see particle size distribution gravel, 4, 15, 17,209,472 correction for, see oversize particles description, l8,23 gravity walls, see walls ground freezin'g, 121,3 14 ground investigation, 248,250,277, 500 et seq contaminated land, depth, extent, in situ testing, see in situ testing methods, 503 et seq reports, 243,244,500, I I

13 544 Index ground investigation (continued) sampling, see sampling ground model, 246,250,253,349, 500,502,522 groundwater, see also piezometer; water table lowering, 83, 171, 176 observations, 512,516 et seq, 521, 523 occurrence, 47,48 removal, gyttja, 15, 17 halloysite, 8, 9, 10 hand augering, see ground investigation, methods head, see pressure headings, see ground investigation, methods heave, 73,74, 88,90, 117, 119,260, 262,308,334,388,389 heaving, 49,50, 89,90 horizontal displacement, 260,308, , , stress, see stress humus, 15, 17 Hvorslev surface, 226, hydraulic consolidation cell, 57, 58,59,165,167 hydraulic fracture, 59,79,81 hydraulic gradient, 51,52,54,55, 56, 65, 69,72,73,74, 87, 278 critical, 73, 91, 158 ice lenses, 118, 119,262 illite, 8, 9, 10, 12,35, 176 inclined loading, see bearing capacity in situ curve, 153, 154 in situ testing dilatometer test, Dutch cone penetrometer, field vane test, 514 pressuremeter, ,516 SPT, index tests, see liquid limit; plastic limit; shrinkage limit a' isochrones, 159, 160 isomorphous suktitution, 7 isotropic soil, 63,70, 106, 110, 127, 134, 156, 157 JacHield, UK, case study, joints, see discontinuities kaolinite, 8, 9, 10, 12, 35 KO condition, see earth pressure, at rest laminated clay, 5, 21, 119, 167, 298 layered profiles, 47,54,55, 69, 85, 87, 88, 134, 135, 137, 139,276, 278,310, 330, 399,401,428, 449,522,524 layering, principle of, 291 leaching, 5, 102,235 leaning instability, 3 14 levees, see flood bank lime stabilisation, 465, limit state design, serviceability, 136,246,247,250,287,288,289 limit state design, ultimate base stability, 388, 389 boiling, 91 characteristic values, see characteristic values correlation factors, see piles design values, see design values foundations, 263,264,279,280, 281,282, 287, 304, 309,310, 315,323 geotechnical, 247 heaving, 73,88, 89,90,247 internal erosion, 73,247 limit states, 190,246 et seq, 249, 250,309 partial factors, see partial factors piles, see piles piping, 74 quick condition, 72,73 reinforced soil, sliding, , slope stability, see slope stability uplift, 71,72, 91,92,93,247 walls, see walls walls, surcharge, line load, 134,135,374,375 liquidity index, 9, 13, 31,32,35,44, 234 liquid limit, 15, 16, 19,20,22, 33, 34,3543, 118, 179,212,234, 297,410,465,488 local shear failure, 265 Lodalen, Norway, case study, loess, 6, 15 Los Vaqueros Dam, California, USA, case study, 74 M6 Motorway, UK, case study, made ground, 1, 14, 15,22,23,207, 503 median size, 27,40 Mexico City, Mexico, case study, 155, Mexico City clay, 179 middle third rule, 269,381 k model factors, 248, 331, 354 modulus bulk, 194 drained, 163,164,297,298,304, 305,516 effect of strain, 252, , 299,300,321 increasing, 134, , 293, 299,301,321,346 shear, 193 undrained, 289,291,292,293, Young's, 193 Mohr-Coulomb relationship, 199, 266 Mohr's circle of strain, 194, 195 Mohr's circle of stress, 200, 201, 217,218,238,360,361,362 moisture condition value, 467, ,486,490 moisture content, 9, 13, 15,22,30, 31, 33,37,38,40,41, 163, 179, 448 moisture sensitivity, 471,472,488, 489

14 Index 545 monitoring, 244,277, 309, 312,313, 314,350, , , 443,500,502,521 montmorillonite, 8,9, 10, 12,35, 277 mudflows, 417,419 negative skin friction, see piles normally consolidated clay, , 102, 104, 107, 108, 136, 151, 152, 153,156, 157, 164, 179, 219,220,221,223,225,227, 294,296,298,302,422,423 observational method, see Design oedometer settlement, see settlement test, 110, 116, 128, 157, , 206,302 organic soils, see peat outwash deposits, 4 overconsolidated clay, 101, 102, 103, 104, 105, 107, 108, 112, 125, 127, 134, 136, 151, 152, 153, 154, 164, 181,219,220,221, 222,223,294,296, 302,422, 423 overconsolidation ratio, 102,103, 104, 105, 108, 112, 125, 126, 152, 181,214,229,230,294, 298,335,516 oversize particles, 31,43, 56, 208, 217,468,469,478,482,484, 488,494,495,496 overturning, 268,313,380,383,384 packer test, see permeability packing, state of, 12, 13, partial factors actions, 252 anchors, 251 angle of shearing resistance, 252 bearing, 252 effective cohesion, 252 foundations, 279,280,281,282 groundwater, 72 heave, 88, 89,90 negative skin friction, 342 piles, 251,329, 330,331, 340, 352,353,354,357 sliding, 252, slope stability, 425,426,427, 428, 430,432,434,435,438,441, 442,443,450,451,455,456 unconfined strength, 252 undrained shear strength, 252 uplift, 72, 92, 93 walls, 385,386,402,403, walls, surcharge, 373,374 weight density, 252,428 particle density, 15, 16,22,23,37,38, 39, 91,179 effect on strength, 12,210,211 mineralogy, 6,209,218 shape,6, 12, 13, 18, 19,22,24, 210 size distribution, 13, 16, 17, 18, 22,24,25,26,27,28,40,52, 53,77,210,465 passive pressure, see earth pressure peat,3,6, 14, 15, 17, 18,23,29,31, 34,83,295,298,303,473 classification, 16, 17 description, 16, 17,22,23 secondary compression, see secondary compression perched water table, 48 permafrost, 118, 119, 121,262 permeability borehole tests, 58,59, 60,61, 86 coefficient, 51,52,54-61, 167, 173,182,184 empirical values, 53,54 laboratory tests, 55,56,57, 58,59, 84 layered soils, 54,55, 85 packer test, 61,62 piezometer test, 62,63, 87, 167 pumping test, 63,64 triaxial, 58 typical values, 51,53, 54 personnel, 243 PFA, 1,29,465,487 phreatic surface, 48,68,75,76, 97, 440 piezocone, 5 13 piezometer, 48,71 hydraulic, permeability test, 87 pneumatic, 518,519 standpipe, vibrating wire, 5 19 piezometric head, 48,52 level, 48 observations, 516,517 pile groups, block failure, 327,344,345 efficiency, ,345 individual pile penetration, 344, 345 load variation, 334,343 pile cap, 327, 329, 342, 344,345 serviceability limit state, 328,331, 340,345,346,347,352 settlements, 345,346, 347, 349 spacing, 334,342,343,344,345, 346 stiffness, 342, 343, 349, 352 stressed zone, 343,349 piles, 326 et seq bored, in clay, ,336, 353, 354 bored, in sand, 339,340 critical depth, ,356 driven, in clay, 332,333, , 355 driven, in sand, ,349, 356 factor of safety, 340,341,346 layered deposits, 330,333, 341 limit state design, 326,327, 328, 340,341 correlation factors, 329, 330, 331,352- model factors, 331,354 ultimate capacity, 344,345,352 load tests, 327, , 341,349, 350,351,354 negative skin friction, , 356,357 case study, types, 326,327

15 546 Index piles (continued) ultimate compressive resistance from static load tests, , 352 from ground test results, 330, 353,354 from other methods, weight of pile, 33 1 piping, 48,50,59,73,74 piston sampler, plane strain condition, 192,193,205, 206,210 plastic limit, 20,22, 32, 33, 176,465, 468,488 plasticity behaviour, 19,20,31, 34, 197, 198,200,277,471,472 chart, 20,34,35,44 index, 34, 35,44, 118, 120, 179, 214,219,220,222, 232,234, 259,260,297,301,465 terms, 20,35 point load, 133, 134, 135, 136, 144, 255,374,375 Poisson's ratio, 194,289,299, 301, 346 pole, 191, 192, 194,200 polluted soils, 2 pore pressure, see pressure porosity, 12, 13,38,45,51 pozzolana, 485 precompression, , 186 preconsolidation pressure, 100, 102, 151, 152, 154, 155, 179, 191, 296,302,307 pressure change in pore, 108, 109, 110, 123, 124, 127, 128, 157, 158, 159, 184,204,237,298,334, 350,422,439,445,467 construction, 123, 124, 170,424, 467,488,489 head, 51,62,67,70,71, 87, 88, 89,91,371,372 initial pore, 109, 157, 159, 160, 161 minimum and maximum, 3 8 1, minimum equivalent &id, 369 parameters, pore, 110, 111, 112, 124, 128, 129,218,223,236, 237,238,298,440 pore, 51,89,97,98,99, 100, 129, 158, 159,216,223,371,372 pore pressure ratio r,, 427,435 uplift, 69,71,73, 89 pressuremeter test, ,5 16 principal stress, see stress, principal propped walls, see walls pumice, 15 pumping test, see permeability quick clays, 5,6,234,418,445 quick condition, 72,73 raft foundations, 132, 133, 137, 139, 141, 145,255,258,277,290, 315 rapid drawdown, 204,424 reinforced soil, 377 construction, design, , reinforcement, 389,390 relative deflection, 308 relative density, see density index Reports Geotechnical Design, 243,244, 500,520 Ground Investigation, 243,244, representative values, see characteristic values residual strength, see seen,@ retaining structures, see walls rigid foundation, 132, 133, 134, 139 ring shear test, 206 risk, ,443,502 certification, 245 register, 245,500 rocks, weathered, 3, 17 Roscoe surface, 226, rotary drilling, ,523 rotation, 308,309, 323 rotational failure, 419,429 et seq running sand, 49,83 safety margin, 190, 370, see also design values sampling block, 509 Delft continuous, 5 11 disturbance, 211, 504, 508 groundwater, 5 12 piston, quality, 508,509,521 split-barrel SPT, 509, 510, thin-walled tube, 509,510 U100, ,523 window, sand allowable bearing pressure, 272 et seq, 284,287 bearing capacity, see bearing capacity description, 17, 18,22,23,3 1,40 drains, 172 frost action, 118, 121 normally consolidated, 108, 136, ' 305,306,339 overconsolidated, 108, 136, 305, 307,337,339 parameter Af, 112 permeability, 51, 52,53,54, 84 replacement test, 29,30 settlements, 150, 304 et seq shear strength, see shear strength stiffness, 132, 133, 136,207 saprolite, 3 saturation back pressure, 57, 58, 127, 168 capillary rise, 99, 112, 113 degree of, 37,45, 112, 164,493 line, see air voids, lines partial, 13, 37,38,97, 99, 111, 112,113,114,115,116,218 process, 223,236 triaxial, 236,237 zone of, 113, 114 Schoharie Creek, USA, case study, scoria, 15 scour, see erosion secant bored pile walls, see walls

16 Index 547 secondary compression, 103, 154, 155, 156, 158, 163, 165, 166, 167,175,295, ,305, 349,400 sedimentation test, 25,26 seepage anisotropic soils, 68,69 deflection rule, 68,69 effect on slope stability, 426,427, 445 flow nets, 66, 67, 68, 69, 70, 74, 37 1 force, 72, 83,90 pressure, 72, 89 quantities, 54, 69,70, 87, 89,91 theory, 63 et seq selected materials, 464,465 sensitivity, see clay serviceability, see limit state design settlement, see piles settlement, consolidation, 287,295 et seq, 313,316 compression index, 163, 164, 179, 180,181, ,319 oedometer, 184, 185,295, ,299,320. time, 150, 161, 170, 171, 172, 174, 175, 178, 184, 185, 186, 187 settlement, immediate, 287,288,289 et seq, 3 17 average, 289,291,292, 318 depth correction, 289,291,318 during construction, 171,289, 298,299,301 general method, 289 modulus estimates, modulus increasing, 289, ,301, principle of layering, 289,290, 291,317,318 principle of superposition, 289, 290,317 rigidity correction, 289,290,318 yielding, 288,292,294,319 settlements, permissible, 307 et seq, allowable, 272,304, 307 criteria for movements, 287,288, 309 damage criterion, 272,309,310, 323,349 definitions, routine limits, settlements, regional, ,295, 296,313,315 settlements, sand, 150,272, 304 et seq, 3 14 Burland and Burbridge method, , Schmertmann method, , settlements, secondary, 295 coefficient of, see coefficient of settlements, total, 287,298 et seq general method, elastic drained method, 299,300, 301,321 individual piles, modulus, drained, 297,298,299, 300,301,321 pile groups, 345,346,347 rigidity correction, 299 Skempton-Bjermm method, 298, 320 shape factor, 59,60,61, 62, 63,70, 86,267,306 shear strength, see strength shear surfaces, 4, 231,419 sheet piling, see also cofferdams, anchored or propped, 377,378, boiling, 91 cantilever, heave, 73,74,90 piping, 48, 59,73,74 seepage, 68,89 shell and auger, see cable percussion boring shell fra,.ments, 6 shrinkage, 259,260,261, 307,473, 474 shrinkage limit, 22, 32, 36 sieving, see particle, size distribution silt, 15, 19,20,23,26,31,34,79,81, 84,119,120,123 site investigation, 499 et seq desk study, 501,519,520,522 ground investigation, see ground investigation site inspection, 501,519,520,522 skin friction, 71,92,93,207,266, 272,330, 336,338,339, 364, 365,366,367,369, 382, see also piles; negative skin friction slickensided surfaces, 5,22,277,476 slides, see slope stability sliding, 266,268,271, ,382, 403 slope stability, see cuttings; earth dams; embanlanents Bishop simplified method, ,435,446,453,454, 457,458 circular arc, undrained, critical circle, 430,434,445,452, 453,454,455 dry slope, 426,436,437,438,439, 449 effective stress, 425,432 et seq, 445,446,449,450,453,454, 455 factor of safety, 425,426,427, 430,431,432,433,434,435, 438,440,441,442,446,449, 452,453,454 limit state design case study, Nicolet landslide, 418 circular arc, 430 effective stress, 432,434,435, 438,441,442,443,453,455 first-time slides, 420, mass movement, 417, method of slices, ,45 1 natural-slopes, 417,420, non-circular, overdesign factor, 430,435, 438,453,455,456,458 plane translational slide, ,447448,449,450 pore pressure ratio, 427,435, 438

17 548 Index slope stability (continued) limit state design (continued) pre-existing slip surfaces, 419, 420,421, progressive failure, 420 rapid drawdown, 427,439,440 serviceability, 443 stability coefficients, 43 1,435, 437,438,453,456,457 stability number, 431, 432 submerged slopes, 427,439, 457,458 tension crack, 428,429, three-dimensional, 446 undrained, 428,429, , 451,453 vertical cuts, 428,429,451 water table, 422,423,425,426, 436,437,438,439,445,447, 449 wedge method, smectite, see montmorillonite softening, 332 soil aeolian, 6 classification, 14 et seq description, 14 et seq, 22,521,523 extraction method, 3 15 formation, 1-5 glacial, see glacial deposits marine, 3,5 model, 36, 37,38 moisture, 113 nailing, 389 section, 522,524 stiffness, 132, 134, 136, , 295,305,319,485 strength terms, 20 structure, 10, 11, 12, 13 tropical, 3 solum, 3 specific gravity, see particle density specific volume, 38, 156,225 spread foundations, see foundations, spread stability coefficients, see slope stability a' stability number excavations, 387,388 slopes, undrained, 431,432 standard penetration test, 18,20,30, 206,207,272,273,274,284, 299,304,306,307,322,330, 338,503, ,523 standpipe, 517 standpipe piezometer, stone, see gravel strain control, 205,208,213,215,224 effect of, 194,196,395 normal, 192, 194 rate of, 208,215,224 reinforced soil, 396 representation of, 195, 198 shear, 192, 193, 194,205 volumetric, 194,240 yield, 196, 198 strength critical state, 224 et seq, 196, 197, 198,208,210,211,239,240 dry, 19 effect of drainage, 202,203,205, 206 effective stress or drained, clay, 211 et seq, 203,205,206,208, 215,216,222,223,224,369 failure criterion, 196,199,200 failure mode, 190,196 peak, 179,196,197,198, ,222,236,448 residual, 196,197,198,206,207, ,420,446,448 ring shear test, 206,207,212 sand, 206 et seq shear box test, 206,207,208,212, 236 test procedures, 203,205,221 triaxial, see triaxial test ultimate, 196, 197,236 undrained, clay, 20,21,202,206, 207,208,211,212,213,214, 215,216,217,218,219,223, 237,238,276, 301,332,334, 335, 344,369,372,428,429, 468,469,471,514 vane, see vane test variation with depth, yield, 196 stress effective, 98, 99, 100, 102, 103, 105,106,125,126,127,128 effective, above water table, 113, 114, 115, 127, 129 history, 98, 101, 102, 151, 152, 155,156,206,221 horizontal, 97,104, 105,106,107, 126, 127,316,336,337,339, 360, see also earth pressure in the ground, 97 et seq paths, 106,201,202,227,228, 229,230,238,239 principal, 103, 104, 105, 110, 111, 191 et seq shear, 19 1 et seq total, 28,97,98, 99, 100, 105, 106,125,126 stress distribution bulbs of pressure, 137,276,277 circle, 133, 136, 169 line load, 134,135 Newmark's method, 137, 139,145 on walls, see earth pressure point load, 134, 135, 144 principle of superposition, 137, 138,141,145,147 rectangle, flexible, 133, 137, 138, 140,145,146,169 rectangle, rigid, 133, 139, 141, 147 strip load, 136,137, 138, 140, 144, 169 trianplar load, 141,142,147 uniform pressure, 13, 134, , ,168,169, 296 structure, 9, 10, 11, 12, 13,21, 167, 168,213,235 structure, mass, 21,203 submerged density, 90,98, 100, 125,217,427 slopes, 427,439,457,458 subsidence, ,295,307 suction, 99, 103, 104, 113, 114,115, 116, 117, 118,259,260,427

18 Index 549 sump pumping, 48 super-elevation, 263 surcharging, , 186 surface area, 9 swelling, 116, 117, 118,307,473 swelling index, 163,164,219,296,297 swelling pressure, 116 Tancred Pit Borehole, Yorkshire, case study, 82 temperature, effect of, 15, 30, 33,52, 53, 118, 119, 121,259,260, 262,307 tension cracks, 372,373,428,429, 45 1 Teton Dam, USA, case study, 74,79, 80,81 thixotropy, 102,155,179,235 till ablation, 4 lodgement, 4 melt-out, 4 tilt, 270,277, 308, 309,312,313, 314,315,381 time factor, 159, 160, 161, 162, 164, 165, 166, 167, 172, 174, 184, 185,186,187 topsoil, 15,464,465,473 Tower of Pisa, Italy, case study, Transcona Elevator, Canada, case study, translational slides, see slope stability trees, effects of, 115, 116, 117,260, 26 1 trial pits, 451 triaxial apparatus, 58 triaxial test, 214 et seq compression, 127,202,205,206, 207,215 consolidated drained, 206,212, 216,221,224,240 consolidated undrained, 206,212, 221, ,236,237,238 extension, 110,202,205,206 multi-stage, 217,218 quick undrained, 206,215,216, 217 rate of strain, 215, 224 saturation, 223,236,237 tropical soils, 3 unconfined compression test, 212 undisturbed samples, see sampling undrained, see drainage; shear strength uniformity coefficient, 27, 28, 40, 210,465 unit weight, see weight density uplift, 50,70,71,91 Usk dam, UK, case study, 123 vane test, 206,211,212,213,214, see also in situ testing varved clay, 4,9,21,53,54, 167 Venice, Italy, case study, , 296 void ratio, 12,29,38,45, 91, 99, 150, 158, 159, 163, 164, 179, 210,493 constant, 210 voids, 50,51 volcanic soil, 14, 15, 16, 33, 179 walls adhesion, see adhesion anchored or propped, 377, basement, 376, 377,378,379 cantilever, 363,364,377, , cofferdam, see cofferdams contiguous bored pile walls, 377, 383 crib, 377,379 diaphragm, 377,383 embedded, 247,371,372,376, 377,378,382 et seq, 386 gabion, 377,379 gravity, 370,371,377, 379 et seq, masonry, 376,377 reinforced soil, see reinforced soil secant bored pile walls, 377, 378, 383 sheet pile, see sheet piling wall friction, see skin friction waste materials, see made ground water table, 48,47,49, 60, 81, 82, 100, 103, 113, 114, 116 capillary rise above, 99, 104, 114, 295 correction, 274,284 effect on bearing capacity, 263, 271,274,280,284,313, 314, 337 effect on earth pressures, 370,371, 372,402,403 effect on slope stability, see slope stability effective stresses above, 103, 115, 125 instruments for, see groundwater, observations on borehole record, 523 on soil section, 524 water-borne soils, 314 weathering chemical, 2, 12,33,235 clay, 102,235 grades, 2,3,22 mkchanical, 2 oxidation, 5 wedge method active thrust, passive thrust, reinforced soil, 394, 395,396 slope stability, weight density, 28, 29,38,40,41,97 Westergaard material, 135 wind-blown soils, 6 yield, 196, 197, 198 Young's modulus, 193