## Preconsolidation Pressure By British Standard Code

active earth pressure, 196-8, 211-14,

219-21 activity of a clay, 126, 127 adhesion factor, 303 adsorbed water, 61 aeration zone, 35, 36 air dried soils, 9 air voids line, 388 air voids percentage, 396 allowable bearing pressure, 269, 292, 293, 348, 349

allowable settlement, 349

analogy of consolidation settlement, 352

anchored earth, 267, 268

anchored walls, 258

angle of obliquity, 83

angle of friction, 83

angle of shear resistance, 89

anisotropic soil, 68

assessment of traffic, 407

Atterberg tests, 10

backfill, 223 backfill drainage, 224 back pressure, 102, 103 basalt, 2

base materials, frost susceptibility, 407 bearing capacity coefficients, 275, 279, 280 bearing capacity of a pile, determination of, 303-6

bearing pressure, allowable, 348, 349

bentonite suspension, 474

Bishop and Morgenstein's curves for slope stability, 179, 190-95 bitumen emulsion, 474

block failure of pile groups, 309 bored and cast-in-place piles, 300, 301 bored pile walls, 244, 245 boring rig, 461

Bousinesq theory for stress distribution,

138-40 boulders, 19

British soil classification system, 15 British standard compaction test, 384, 385 brittle soil, 11

BS 8002 design method, 245, 246 bulbs of pressure, 144-6 bulk density, 27 bulk density determination by core-cutter, 397 by penetration needle, 398 by radiation, 398 by sand replacement, 397 bulk unit weight, 27 buoyant density, 27 buoyant unit weight, 26

California bearing ratio test, 401, 403 California bearing ratio test, surcharge effect, 403

capillarity, 58-61

capillary effects, 60, 61

capillary fringe, 35

capping layer on subgrade, 405

cavitation, 419

cement grouts, 474

chalk, 3

chemical grouts, 474 classification of soil, 6 closely graded, 8 clay, 3

clay, activity of, 126, 127

clay cutter, 461, 462

clay deposits, 4

clay minerals, 4, 5

clay soils, swelling and collapse, 431

clay structure, 5

cobbles, 19

coefficient of consolidation, 358, 359, 360 coefficient of friction, 83 coefficient of permeability, 37, 44 coefficient of permeability, determination of approximated values, 44 constant head permeameter, 37, 38 falling head permeameter, 39, 40 pumping in test, 43, 44 pumping out test, 41-3 coefficient of volume compressibility, 327, 328

cohesion, 88, 90, 91

cohesionless soils, settlement estimation Meyerhof's method, 318 De Beer and Martens' method, 319 Schmertmann's method, 319 cohesive soils, immediate settlement, 313 compaction

British standard test, 384, 385 correction for gravel, 389 end-product specification, 395 method specification, 395 plant, types of, 392 relative, 395

specification by air voids, 396 vibrating hammer method, 385, 386 complex stress, 83 composite piles, 301 compressibility factor, 423 compression curve, normally consolidated clay, 332

compression curve, overconsolidated clay, 332

compression, elastic, 312 compression index, 332 compression, primary, 312, 358 compression, secondary, 312, 358 cone penetrometer, 13 consolidated undrained shear test, 102 coefficient of, 358, 359, 360

consolidation coefficient of, 358, 359, 360 degree of, 352, 356 during construction, 364, 365 general, 335 isotropic, 442, 443 model law of, 362 one dimensional, 324 rate of, for sand drains, 380 settlement, 324 settlement, analogy of, 352 test, 324, 325, 326, 334, 335 test, determination of coefficient of permeability, 360 test stress paths, 344, 345 theory of, 353, 354, 355, 356 two or three dimensional, 367, 374 virgin curve, 331 contact moisture, 61 contact pressure, 148, 149 continuous sampling, 464 core-cutter, 397

Coulomb's law of shear strength, 88, 89 Coulomb's modified lawn, 90 Coulomb's wedge theory, 200, 201, 214, 215,

233-5 counterfort wall, 242 CP2 design method, 254 crib walls, 242

critical hydraulic gradient, 52, 53 critical slip circles, 154, 155, 158-60 critical state theory critical state, 442 critical state line, 447 drained stress paths, 458 Hvorslev surface, 456, 457 overall state boundary, 455, 456 Roscoe surface, 452-5 symbols, 441, 442 undrained stress paths, 458 wet and dry regions, 456 Culmann line, 202-4

Darcy's law of saturated flow, 37 deep foundations, 270, 317 degree of consolidation, 352, 356 degree of sample disturbance, 464

degree of saturation, 23, 417

effect of, 434 density, 26

depth factors, 279, 281

description of soils, 22

diaphragm walls, 244

direct shear box test, 92

disturbed samples, 463

dilatancy test, 6

drainage, of backfill, 224

drainage path length, 357, 358

drainage with geotextiles, 475

drained shear test, 101, 102

drained stress paths, critical state theory, 458

driven and cast-in-place piles, 299, 300

driven piles, 296, 297

dry density, 27

dry unit weight, 26

dynamic consolidation, 473, 474

earth dams, 62-6

earth dam, construction pore pressures, 372 earth pressure at rest, 229 earth retaining structures anchored earth, 267, 268 anchored walls, 258 base resistance to sliding, 248, 249 bearing pressure, 247, 248 bored pile walls, 244, 245 conterfort wall, 242 crib walls, 242

design of, 245-9, 252-4, 258-61, 263 diaphragm walls, 244 gabion walls, 243 limit states, 247

mass construction gravity walls, 240 mobilisation factory, 246 propped walls, 258 reinforced concrete walls, 241, 242 reinforced soil, 264, 265, 266 relieving platforms, 241 sheet pile walls, 240, 252-5 eccentric loading, 282, 283 effective permeability for anisotropy, 69 effective size, 7

effective stress in unsaturated soils, 432 effective stress, saturated soils, 58, 89

effective stress strength parameters, determination of consolidated undrained test, 102 drained test, 101, 102 tests with back pressure, 102, 103 elastic compression, 312 elastic limit, 134 elasticity, modulus of, 317 electrical analogue, 72, 73 elevation head, 36 electro-osmosis, 472 embankment, rapid construction, 167 end bearing piles, 295, 296 end-product compaction, 395 environmental geotechnics, 476 equation of flow, 44-6 equilibrium moisture content, 425 equipotential lines, 47

equivalent isotropic consolidation pressure, 444 excess hydrostatic head, 36 extension test, triaxial, 109, 110

facing units, 265

failure plane, 86

filter, high air entry, 170

filter paper method, 421

filters, design of, 54-6

filtration, with geotextiles, 475

fixed earth support method, 259, 260

flexible footing, contact pressure, 148

flexible pavement, 400

force, 26

flow lines, 47

flow lines, refraction of, 77, 78

flow nets, 47-52

foundations, deep, 317

foundations, shallow, 317

free earth support design method, 259

French drains, 405

frequency of sampling, 464

friction, 62, 83

friction piles, 296

frost susceptibility, 407

gabbro, 2 gabion walls, 243 gap graded, 8

general consolidation, 335

general consolidation stress paths, 345, 346

geotextiles, 265, 474, 475

geological maps, 460

grading of a soil distribution, 7

granite, 2

granular slopes, 151 granular soil, 4 gravel, 3

gravel content, correction for, 389 grid roller, 393

gross pressure design method, 254 ground water, 2 ground water level, 2 group symbols, 19 ground improvement base separation, 475 compactive techniques, 472 drainage, 475

dynamic consolidation, 473, 474 electro-osmosis, 472 filtration, 475 geotextiles, 474, 475 grouting techniques, 474 reinforcement, 475 stage construction, 472 surcharge loading, 471, 472 vibro-compaction, 473 vibro-flotation, 473 vibro-replacement, 473

high air entry filter, 170 hydraulic gradient, 47, 48 hydraulic piezometer, 170 hydrostatic head, 36 hydroscopic water, 36

igneous rock, 2 illite group, 5

immediate settlement of cohesive soils, 313 inclination factors, 279, 283 inclined loading, 282, 283 influence of wall yield, 229, 230 initial excess pore water distribution, 353 induced stresses in a soil mass by self weight, 136 by uniform loading, 137 by point load, 138

in-situ classification of soil, 6, 19 in-situ compaction, m.c. values, 394 in-situ compaction, specification of, 395 intermediate belt, 35 intrusive igneous rock, 2 isotropic consolidation, 442, 443 isotropic soil, 46

jacked piles, 299

kaolinite group, 5 kappa, or swelling line, 443 Kf line, 344 Ko line, 344

lagoons, 66, 67

lambda, or normal consolidation line, 444

large diameter bored piles, 301 laterite, 3

limit of elasticity, 135

limit of proportionality, 135

limit state design method, 245, 246, 252

line load surcharge, 206

liquidity index, 11, 125

liquid limit, 10

liquid limit test, 12, 13

M-soil, 18

Maclaurin's series, 367 macro structure, 5 magma, 2 marble, 3

mass construction gravity walls, 240 matric suction, 417, 418 metamorphic rock, 3 method compaction, 395 microstructure, 5 model law of consolidation, 362 modulus of elasticity, 317 Mohr circle diagram, 84, 85 Mohr-Coulomb yield theory, 90

applied to triaxial test, 121, 122 moisture condition value, 408 moisture condition value, calibration line, 412

moisture condition test, suitability of, 418

moisture content capacitance probe, 399 determination of, 398

determination by time domain reflectometry, 398

determination by speedy tester, 399 moisture content, 9 montmorillonite group, 5 optimum, 387

N values, corrections to, 290, 291 negative skin friction, 308 net passive resistance design method, 254 net total pressure design method, 255 neutral stress, 89

Newmark chart for vertical stress, 142-4 newton, 26 nominal stress, 134

normally consolidated clay, compression curve, 332

normal consolidation or lambda, line, 444 normal stress, 84 normally consolidated clay, 113 numerical methods for seepage problems, 73,74

obliquity, angle of, 83 occlusion, 103

octahedral normal stress, 120 octahedral plane, 120 octahedral shear stress, 120 one dimensional consolidation, 324 open standpipe, 169 operative strengths of soils sands and gravels, 118 silts, 119

soft or normally consolidated clay, 119 overconsolidated clay, 119 organic soil, 3 osmotic suction, 420 oven dried soils, 9 overburden, 113 overcompaction, 394 overconsolidated clay, 113 overconsolidation ratio, 113

pad footing, 269 parabola, 164

parabolic solution for seepage, 63, 64

pascal, 81

passive earth pressure, 196, 187 pressure head, 36 partially saturated soil, 417 particle size distribution, 6 particle specific gravity, 24, 25 pavement, 400 pavement, flexible, 400 pavement, rigid, 400 peat, 4

peat, amorphous, 4

peat, fibrous, 4

peat, pseudo-fibrous, 4

penetration needle, 398

permeability of sedimentary deposits, 74, 75

pF values of suction, 418

pier foundation, 270

piezometer, 170

pile foundation, 270

pile foundations block failure of groups, 309 bored and cast-in-place, 300, 301 composite, 301 driven, 296, 297

driven and cast-in-place, 299, 300

driving, 297-8

end bearing, 295, 296

friction, 296

groups, 308-10

jacked, 299

large diameter, bored, 301 precast concrete, 296 screw, 299

settlement of groups, 309, 310 steel, 297 testing, 301-3 tests, 301-3 timber, 296 vibrated, 299 piping, 53, 54 planar failure surfaces, 181 planar translation slip, 181-3 plasticity, 18 plasticity index, 10 plastic limit, 10 plastic limit test, 13 plastic solid, 10

plate loading test, 288, 289, 293, 323 pneumatic-tyred roller, 392 Poisson's ratio for soil, 337 poorly graded, 8

pore pressure coefficient A, variation of, 117,118 pore pressure coefficient B, 467 pore pressure coefficients A and B, 105-9, 167 pore pressure ratio, 153, 167, 179, 180 pore pressure ratio for steady seepage, 168 pore pressure parameters Ba and Bw, 440 pore water pressure, 89 porosity, 23

potential functions, 46, 47

precast concrete piles, 296

preconsolidation pressure, 113

presumptive bearing capacity values, 294, 295

primary compression, 312, 358

principal plan, 83

principal stress, 83

properties of soil, 22

proportionality limit, 135

propped walls, 258

Psychrometer method, 421

quicksand, 53

radiation, bulk density determination, 398 raft foundation, 269 rammers, 393

Rankine's theory of earth pressure, 198, 211,

232, 233, 235 rapid construction of an embankment, 167 rapid drawdown, 152, 168, 169 refraction of flow lines, 77, 78 reinforced concrete walls, 241, 242 reinforced soil, 264, 265, 266 reinforcing elements, 264, 265 relative compaction, 395 relative density, 30 relative humidity, 419, 420 relieving platforms, 241 residual factor, 130 residual soil, 3 residual strength of clays, 128, 129 of sands, 129

of silts and silty clays, 129

residual strength of soil, 127-30, 458

reversed filters, 56

rigid footing, contact pressure, 148

rigidity factor, 316, 341

rigid pavement, 400

road, design life of, 408

rock, 2

Roscoe surface, 452-5 Rowe oedemeter, 326, 327

safe bearing capacity, 269, 278, 279, 294 sample tube, 461, 462 sampling continuous, 464 degree of disturbance, 464 disturbed samples, 463 frequency, 464

undisturbed samples, 463, 464 sand, 3

sand drains, 377, 380, 381 sand replacement method, 397 sands, behaviour under shear, 113, 114 sandstone, 3

saturated cohesive soils, behaviour under shear, 114-17 saturated density, 27 saturation, degree of, 23, 417 saturation line, 388 saturation zone, 34, 36 saturated unit weight, 26 screw piles, 299

secondary compression, 312, 358 sedimentary deposits, permeability of, 74, 75 sedimentary rock, 3 seepage forces, 53, 152 seepage patterns in an earth dam, 62, 63 seepage quantities from flow nets, 49, 50, 69 seepage tank, for flow problems, 73 seepage through different permeabilities, 76, 77 sensitivity of clays, 125 separation of pavement base, 475 settlement, consolidation, 324 settlement estimation for cohesionless soils De Beer and Martens' method, 319 Meyerhof's method, 318 Schmertmann's method, 319 settlement, allowable, 349

settlement of foundation on cohesive soil, 312

settlement of pile groups, 309, 310 shale, 3

shallow foundations, 270, 317 shape factors, 279, 281 shear resistance, 196 shear strength, 82 shear stress, 84 sheepsfoot roller, 393 sheet pile walls, 240 shrinkage limit, 11 silt, 3

site investigation, 459 site investigation report, 469-71 skin friction, 304 slate, 3

slopes, granular materials, 151 slope stability, effective stress analysis, 167, 170-74

slope stability, total stress analysis, 155 slopes with cohesive and frictional resistance, 154

smear effects in sand drains, 381

smooth wheeled roller, 392

soil, 2

soil belt, 35

soil classification, 6, 15

soil design parameters sands and gravels, 221, 237, 277 silts, 221, 238

soft or normally consolidated clay, 221, 237, 277

overconsolidated clay, 221, 237, 277 soil moisture capacitance probe, 299 soil nailing, 266 soil profile, 468 soil properties, 22 soil survey maps, 460 space diagonal, 120 speedy moisture tester, 399 square flow net, 49

square root of time fitting method, 359 stability number, 163, 164 standard penetration test, 118, 289, 290-93 static cone penetration test, 294, 306 steel piles, 297

stratification, 68, 69 stream functions, 46, 47 strength envelope, 86, 343 strength factor design method, 254 stress invariants, 124

stress paths for general consolidation, 345, 346

stress paths in the consolidation test, 344, 345

stress paths, two-dimensional, 342, 343, 344

strip foundation, 269

strutted excavations, 231

subsoil, 2

subgrade, 400

subgrade capping layer, 405 subgrade, frost susceptibility, 407 subgrade, strength and stiffness, 400, 405 subsurface water, 34 surface tension, 58, 59 soil suction compressibility factor, 423 equilibrium moisture content, 425 filter paper method, 421 measurement of, 420 pF values of, 418 psychrometer method, 421 suction, 417 tensiometer, 422 soil structure changes 429-31 stage construction, for ground improvement, 472

standard penetration test, 465 standpipe, 169, 467

stresses at a point in an elastic medium, 135, 136

stress paths in three dimensions, 445 stress paths in three dimensions, trial test, 449-52

stress-strain relationships, 134, 135 surcharge loading, for ground improvement

471, 472 Swedish method of slices, 157 swelling and collapse of clay soils, 431 swelling, or kappa, line, 443

tailings dams, 66, 67

Taylor's curves for slope stability, 163 5

Taylor's series, 368

tensiometer, 422

tension cracks, 156, 213, 222 test, or trial, pits, 461

testing techniques for unsaturated soils, 437-40 theory of consolidation 353, 354, 355, 356 thixotropy, 125

three dimensional stress paths, 445 three dimensional stress paths, triaxial test,

449-52 timber piles, 296 time domain reflectometry, 398 topographical maps, 460 topsoil, 2, 3 total stress, 58

total stress strength parameters, determination of direct shear box, 92 biaxial test, 95-7

unconfined compression test, 98, 99 traffic assessment, 407 transported soil, 3 triaxial test, 95, 96, 109, 110, 360 two-dimensional stress paths, 342, 343, 344

ultimate bearing capacity, 269, 275, 276, 279, 301-3

ultimate bearing capacity, determination of bearing capacity equations, 275, 276, 279 depth factors, 279, 281 earth pressure theory, 270, 271 general shear failure, 274 inclination factors, 279, 283 local shear failure, 274 non-homogeneous soil, 285, 286 plastic failure theory, 274-6 punching shear failure, 274 shape factors, 279, 281 slip circle methods, 271-3 unconfined compression test, 98, 99 uniformity coefficient, 8 uniformly graded, 8 unit weight, 26

unsaturated soils effective stress, 432

effect of degree of saturation, 433, 434 elasto-plastic critical state models, 437 state surfaces, 437 testing techniques, 437-40 two stress variables, 435 unsaturated soils, 417 undisturbed samples, 463, 464 undrained stress paths, critical state theory, 458 uniform load surcharge, 205 upper flow line in an earth dam, 64, 65

Van der Waal forces, 6

vane test, 465-7

velocity head, 36

velocity, of seepage, 37

vibrating hammer method, 385, 386

vibrated piles, 299

vibratory roller, 392

vibrators, 393

vibro-compaction, 473

vibro-flotation, 473

vibro-replacement , 473

virgin consolidation curve, 331

void ratio, 23

volume compressibility, coefficient of, 327, 328 volumetric change, 326 volumetric strain, 105

wall yield, influence of, 229, 230

water content, 9

water table, 34

water vapour, 419

wedge failure, 183

wedge foot compactor, 393

well graded, 7

yield point, 135 yield stress, 135

yield theory, Mohr-Coulomb, 90

Now in its Seventh Edition, this well established book provides undergraduate and HND students of civil engineering with a core text on the theory and treatments of soil mechanics. The fundamental principles of the subject are explained clearly and logically and their use in practical applications is well illustrated.

The book also features a wide range of worked examples and problems which help to aid student centred learning.

Key features of the new edition are:

• for the first time, an introduction to practical geotechnical design using limit state theory, together with new worked examples

• an outline of the changes introduced by the draft European Geotechnical Design Code, Eurocode 7

• a revised section on unsaturated soils

• new material in a number of areas including soil nailing, highway design, and in situ moisture content determination

• an enlarged text page with more user-friendly presentation

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