Deformation behaviour of railway embankment ... - Liikennevirasto

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100 Figure 6.3:1 Effect of loading history on permanent strain (Brown and Hyde 1975). In a more recent work, Hoff (1999) studied the development of permanent deformations as a function of load history using a loading procedure where the number of load steps and the maximum load are not fixed, but dependent on the materials resistance against permanent deformations. A procedure with 3,000 pulses for each load step was chosen. Figure 6.3:2 illustrates the load pulses applied to a sample in a typical test. This procedure applies quite high stresses on the sample at the end of each load series where rapid development of permanent strains starts. After the high stresses the sample is unloaded and a new series of load steps are applied for a different confining pressure. The process of loading to high stress levels seems to have a limited influence on the resilient behaviour of the sample for the second, third, and forth load series. No conditioning load was applied to the sample before testing. A conditioning load would have been at a lower level of mobilized shear strength than the load steps approaching the failure state and would have made the interpretation of the results more difficult.
101 Figure 6.3:2 Load series for permanent deformation testing (Hoff 1999). Figure 6.3:3 illustrates the development of permanent deformations as a function of loading cycles. Figure 6.3:3 Development of permanent deformations as a function of loading cycles (Hoff 1999). As we can see from Figure 6.3:3, some permanent deformations develop during the entire test. The permanent deformations at low stresses are however limited and develops in the beginning of a load step. At higher stresses the permanent deformations do not stabilise at the end of the step. When this occurs, the material is no longer able to withstand the loads in the long run and a failure condition is reached. This “failure-
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A 5/2006 Deformation behaviour of r
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Finnish Rail Administration Publica
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4 Past investigations have shown cl
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6 Brecciaroli, Fabrizio - Kolisoja,
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8 kuvataan jakamalla jännitykset j
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10 TABLE OF CONTENTS ABSTRACT .....
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12 8.9 Trondheim NTNU/SINTEF’s re
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14 combination of resilient strains
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16 Modelling is an important necess
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18 Figure 2.1:2 Two-dimensional sta
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20 σ xx − σ 3 2 det τ yx σ yy
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22 stresses. As it can be seen from
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24 grains. The resistance to partic
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26 The reason was argued to be that
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28 term matric suction implies the
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30 Figure 3.2.1:1 Idealisation of t
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32 ε ε 2 ν = , (Eq. 3.2.2:4) whe
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34 where sij = σ −σ , (Eq. 3.2.
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36 addition, when both the complexi
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38 supplement continuum mechanics m
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40 Figure 4.2:1 A typical variation
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42 Figure 4.2:3 Modulus of resilien
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44 provided that the applied stress
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46 material (Uzan 1985). Dilation i
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48 Figure 4.5:1 Resilient modulus o
Page 52 and 53: 50 The grain size distribution of g
Page 54 and 55: 52 The grain sizes that determine t
Page 56 and 57: 54 4.6.3 Fines content A simple cha
Page 58 and 59: 56 grained than for fine-grained ag
Page 60 and 61: 58 and the shape of the particles a
Page 62 and 63: 60 Figure 4.7:1 Effect of the wetti
Page 64 and 65: 62 Figure 4.7:3 Modulus of resilien
Page 66 and 67: 64 Figure 4.7:6 Dry -density as a f
Page 68 and 69: 66 Figure 4.7:7 Resilient response
Page 70 and 71: 68 The form index can be measured u
Page 72 and 73: 70 Hovinmoen are gravel materials.
Page 74 and 75: 72 5 MODELLING OF RESILIENT DEFORMA
Page 76 and 77: 74 5.2.2 Resilient modulus as a fun
Page 78 and 79: 76 M r k2 k3 ⎛ θ ⎞ ⎛ q ⎞ =
Page 80 and 81: 78 the model showed good representa
Page 82 and 83: 80 discussed. However it can be exp
Page 84 and 85: 82 et al. (2003) calculated the res
Page 86 and 87: 84 p u = unit pressure (1 kPa), δp
Page 88 and 89: 86 Figure 5.2.5:2 Vertical resilien
Page 90 and 91: 88 2 1 ⎛ ⎞ = A q ε ν p ⎜1
Page 92 and 93: 90 Figure 5.3:2 An example of the c
Page 94 and 95: 92 by incorporating a coefficient o
Page 96 and 97: 94 6 FACTORS AFFECTING PERMANENT DE
Page 98 and 99: 96 cycles. He drew the general conc
Page 100 and 101: 98 accumulated strain, ε p , is co
Page 104 and 105: 102 load” is not equal to the fai
Page 106 and 107: 104 Chan (1990) noticed, in his stu
Page 108 and 109: 106 Youd (1972) studied the behavio
Page 110 and 111: 108 Figure 6.5:2 Comparison of plas
Page 112 and 113: 110 ample fine-grained fractions th
Page 114 and 115: 112 of a dolomitic limestone with a
Page 116 and 117: 114 Fuller curve (Equation 4.6.2:3)
Page 118 and 119: 116 Figure 6.6:7 Elastic and plasti
Page 120 and 121: 118 Figure 6.7:1 Dependence of the
Page 122 and 123: 120 0,7 0,6 Elastic limit Failure s
Page 124 and 125: 122 Figure 6.8.1:1 Influence of fin
Page 126 and 127: 124 explain why the differences in
Page 128 and 129: 126 was then argued that the variat
Page 130 and 131: 128 7 MODELLING OF PERMANENT DEFORM
Page 132 and 133: 130 Figure 7.2:1 Mohr-Coulomb repre
Page 134 and 135: 132 where K p (N) = bulk modulus wi
Page 136 and 137: 134 1993)) have reported that at le
Page 138 and 139: 136 ε 1,p = accumulated permanent
Page 140 and 141: 138 Barksdale (1972) conducted repe
Page 142 and 143: 140 Figure 7.6:2 Relationship betwe
Page 144 and 145: 142 also be employed for pavement d
Page 146 and 147: 144 repeated loads, although adapta
Page 148 and 149: 146 series of specimens (or in a mu
Page 150 and 151: 148 Figure 7.7:5 S-N design models
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150 In conclusion, both Huurman (19
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152 aim to simulate as closely as p
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154 by the American Association of
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156 Confining pressure is applied t
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158 particles. During the test, the
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160 method takes the average value
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162 Figure 8.7.2:2 Schematic illust
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164 through each platen is provided
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166 measured for the 600 mm central
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168 displayed on the monitor in gra
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170 unbound granular materials. The
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172 Figure 8.8.2:2 Permanent axial
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174 performance-related (functional
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176 the six supports of the vertica
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178 under the same isotropic stress
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180 9 CONCLUSIONS 9.1 Resilient def
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182 − Permanent deformation resis
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184 Balay J., Gomes Correia A., Jou
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186 Cheung, L.W. (1994). Laboratory
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188 El abd, A., Hornych, P., Breyss
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190 Hoff, I., Nordal, S., and Norda
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192 Kolisoja, P. (1996b) Large Scal
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194 Mitry, F.G. (1964). Determinati
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196 Plaistow, N.C. (1994). Non-Line
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198 Tam, W.A. and Brown, S.F. (1988
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200 Wellner, F. (1996). Influence o
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