settlement_of_shallow_foundations_on_granular_soils (Lutenegger ang DeGroot)

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Strain Influence factor I"'0 0· I 0·2 0·4 0·5 0·6 0·7Orc~-7_,_~--~--.-----,----,----,---~(I 970) Prorosal(1978) ProposalSquareDepthWidth( I 978) ProposalStrip/48L----~----~--~-----L----~--~----~Figure 5.21 Schmertmann (1970) and Schmertmann et al. (1978) Strain Influence Factors.103
Soil Type.QJNsandy silt 2.5sand & gravelly sand 3.6fme sand and silty fine sand 4fme to medium sand 4.8sand with some gravel 8medium and coarse sand 8fine to medium sand 10sand 10gravelly sand 8-18sandy gravel 12-16In an attempt to quantify the qjN ratio in relation to the grain-size of the soil, Robertson etal. (1983) presented the chart shown in Figure 5.22 which correlates qjN values with mean grainsize,D,., inmm, An alternative approach was presented by Muromachi and Kobayashi (1982) whoshowed that qjN could also be related to the amount of fines (% < #200 sieve) in predominantlygranular soils as shown in Figure 5.23.It is important to note that in order to make proper use of this settlement method with SPTblowcounts, a sufficiently large number of tests are needed within the zone of foundation influence.For this reason, it is suggested that drillers be instructed to perform continuous SPT's within aminimum depth of 2B below the proposed foundation level.5.3.6 Berardi et al. (1991)Berardi et al. (1991) suggested that an elastic approach could also be used along with theresults of the CPT to estimate settlements using Equation 5.79. The values of the influence factor,1, is given in Table 5. 5 and are based on a Poisson's ratio of 0.15. The operational soil stiffness,E', for use in Equation 5.79 is obtained from results relating stiffness to CPT tip resistance, q,where the ratio ofE'/q, is a function of the normalized tip resistance and is different for differentsoil stress history. One such chart, as given by Berardi et al. (1991) was developed by Baldi et al.(1989) and is shown in Figure 5.24. In this figure, the modulus is defmed at a vertical strain levelofO.l% which Berardi et al. (1991) suggest corresponds to the upper limit of the average strain ofpractical interest for foundations placed on normally consolidated sands and overconsolidated sandswhich may include structural fills compacted under well controlled conditions. For recent normallyconsolidated deposits, it may be desirable to reduce the stiffness to account for higher strain levels.In this case, a modulus reduction factor, varying from 0.5 to 0.75 may be appropriate depending onthe anticipated strain level (up to about 0.5%).104
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SETTLEMENT OF SHALLOW FOUNDATIONSON
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ACKNOWLEDGEMENTSThis study was fund
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5.2.6 Alpan (1964) ................
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LIST OF TABLESTable 2.1 Previous In
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Figure 5.9 Schultze and Sherif(l973
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Figure B.8 Updated Douglas Chart (O
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2.0 BACKGROUND - SETTLEMENT OF SHAL
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HORIZONTAL DISPLACEMENT, mm10. 0Not
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3.1 Introduction3.0 DESIGN APPROACH
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4.0 ELASTIC SOLUTIONS FOR ESTIMATIN
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"o2.8-2.4t2.01.61.2(a)iII-~10520.80
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- 0 2:::::>0a::- (!)-Q.1.5 H.......
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2.52.0fl-1 1.5Figure 4.5 Janbu et a
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thus underestimate settlement. A co
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1.00.9 ~--~~~ ~t::$:::"--+-----+---
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1.0~'-o0.90.80.70.60.5~~~-BURLAND\~
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settlement of each layer. The layer
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ifa.=JO" S=Q867xplbxC 80 02 .Cs04 0
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0. I 00. 150.20m'-.NJ:>-~w0w>....<-
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I2IIfvEDG~- ~,..=.33~vc/-""CENTERJL
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" ~...,I...,"~~....."'w 0-~'z z1.0~
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2 - Compute the settlement of one c
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s = settlementq = foundation stress
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4.8 Wahls and Gupta (1994)A method
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Corrections to the SPT blowcount sh
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4.9.1 Standard Penetration TestNume
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there are several techniques that h
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Overconsolidation ratio, OCRFigure
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Table 4.3 Soil Modulus from Standar
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Table 4.5 Soil Modulus from Cone Pe
Page 61 and 62:
Table 4.5 Cont'dReference Relations
Page 63 and 64: Table 4.6 Other Expressions for Soi
Page 65 and 66: Table 5.1 Methods to Evaluate Settl
Page 67 and 68: 19. Stroud (1989)20. Berardi eta!.
Page 69 and 70: -100.-----~-----------------,~-----
Page 71 and 72: the compression of the layer is cal
Page 73 and 74: 20 40 60 dO 100Std. Penetration Res
Page 75 and 76: 40 60 80 100RELATIVE DENSITY, PER C
Page 77 and 78: VIa..LLI0::JVIS P T- NUMBERS OF BLO
Page 79 and 80: Alp an suggested that the correctio
Page 81 and 82: y = soil total unit weightCw = wate
Page 83 and 84: 1000~-------r----~~--------~-------
Page 85 and 86: 00 0·5 1·0 1·5·Ye2•0Figure 5,
Page 87 and 88: s M~87 !1•D.U/B)p~<=::!::':'"'e11
Page 89 and 90: N = uncorrected blowcountC, = embed
Page 91 and 92: I 2 3UNCONFINED COMPRESSIVE STRENGT
Page 93 and 94: ~-~LU-LU~ eJ:.:t::\:!W~~k-----4----
Page 95 and 96: 5.2.19 Stroud (1989)Stroud (1989) s
Page 97 and 98: 'E-z~161412 J-100WIZI.D8 J-4 J- 1jz
Page 99 and 100: N)'Nq140 IIIN'YINcIIII20 80 I/N'Y 1
Page 101 and 102: The soil stiffness is evaluated usi
Page 103 and 104: 1 •••. ... .,1-: •. .......
Page 105 and 106: 5.2.21 Anagnostopoulos eta!. (1991)
Page 107 and 108: Ll.p' = (2P cos 6 8)/rcz 2 [5.91]Ad
Page 109 and 110: 0~·Illso ·~100 II~\~ 0••100 "
Page 111 and 112: 5.3.5 Schmertmann (1970)In what may
Page 113: 4.- Use Equation 5.95 to calculate
Page 117 and 118: IOr---.----,,---,---,,,---,---,----
Page 119 and 120: Table 5.5 Influence Factors for Ber
Page 121 and 122: Table 5.6 Reported Use ofPressureme
Page 123 and 124: q' =net footing pressureB = footing
Page 125 and 126: In order to recognize the strain ar
Page 127 and 128: For different soils Menard suggeste
Page 129 and 130: 5.5 Dilatometer TestMarchetti (1980
Page 131 and 132: Method B - Special MethodThis metho
Page 133 and 134: OCR= [K(OC)/(1-sin ~ )](1 10·' sin
Page 135 and 136: Figure 5.29 Settlement Ratio as a f
Page 137 and 138: 5.6.2 Barata (1973)B arata also poi
Page 139 and 140: 6"';_;51 v = o , 1~ c~ 4 o/:;0-~ "'
Page 141 and 142: and circular foundation; 4B for str
Page 143 and 144: ~N~~~~~~"' ~0.~100 1.0ii..., c. 10
Page 145 and 146: Table 5.9 Comparison of Settlement
Page 147 and 148: 6.0 ALLOWABLE BEARING CAPACITY CHAR
Page 149 and 150: 5lr)lr.tl\)J~2~'§ I~t--·/_'f()()/
Page 151 and 152: 7\~' "'--O&nseVery Dense..___ N=5o-
Page 153 and 154: also noted that "If the pressure co
Page 155 and 156: 6;:.:5~4~~ 3'~~ 2~~tl. I~~',I) 0(c!
Page 157 and 158: capacity is reduced, the allowable
Page 159 and 160: 6.6 Sowers (1962)Sowers (1962) in L
Page 161 and 162: 301-E~. (2-1 1 9)251-201-l\1050~1-"
Page 163 and 164: 800700~- N'qo- 0.05 qo OOB 8~0_!:!.
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It was stated by Mohan et al. (1971
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1 4f--u.-(")1 2C IIVl'->- 1 0z!;;au
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600(a) D/B = 1 (b) D/B = 0.5 (c) D/
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6050z~- 40c:~0u~ 30/v----/0~ 20 ".0
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250----200 ,........15010050•/...
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q. = NJO.Ol2B (kN/m 2 ) [6.27)Equat
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fl(m)6 600~N.:::~~"2 ~~M"5 500-~~4
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0 2 4B,FT10 12Qo =ALLOWABLE BEARING
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0 0 010c"' E~-V> "' 8.£~0-V>drr!'?
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Table 6.2 (continuted)Method lxlm 1
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7.0 LOAD-SETTLEMENT BEHAVIOR OF SPR
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The value of Q/Q, 1 , is essentiall
Page 189 and 190:
Figure 7.3 Nondimensional Load-Sett
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120~-------------------------------
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z00 0.7:5w 0.6f- <t~ 0.5~:::J 0.4--
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qb(s/0=5%)0.5 1.0 150~6-....2"~zUJ
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tDr= 59%q'YB0 20 40 6040 t,-Dr= 47%
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The bearing capacity factors are a
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7.3 Review of Load TestsInitially,
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Table 7.2 Normalized Load-Settlemen
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Table 7.3 Normalized Load - Settlem
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Table 7.4 Normalized Load- Settleme
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0.9* •+.•t * ' '........... ,
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1.0'I' i 'I' i0.9~"' i "'v :'I' "'
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8.0 SETTLEMENTS FROM CYCLIC LOADING
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9.0 RECOMMENDATIONSBased on the res
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4- Martin (1987) Method (PMT)5- Par
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Berardi, R., Jamiolkowski, M., and
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Engineering." Proceedings of the 2n
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Garga, V.K., and Quin, J.T., 1974.
Page 225 and 226:
Kovacs, W.D., Evans, J.C. and Griff
Page 227 and 228:
Meigh, A.C., 1963. "Discussion on S
Page 229 and 230:
Parry, R.H.G., 1978. "Estimating Fo
Page 231 and 232:
Schultze, E. and Sherif, G., 1973.
Page 233:
Tucker, K.D., 1987. "Uplift Behavio
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settlement_of_shallow_foundations_on_granular_soils (Lutenegger ang DeGroot)

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