Deformation behaviour of railway embankment ... - Liikennevirasto

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70 Hovinmoen are gravel materials. Figure 4.8:4 shows resilient moduli for some of the tests performed in Tampere. The moduli cannot be directly compared because compaction, test procedures, and grain size distribution are different, but the results seem to have the same tendencies as the results from this investigation. 1000 900 800 700 600 500 400 300 200 100 0 0 - 50 mm Hovinmoen 0 - 32 mm Hovinmoen 0 - 32 mm Hovinmoen 0 - 32 mm Hovinmoen 0 - 32 mm Hedrum 0 - 32 mm Steinskogen 0 - 32 mm Visnes 0 - 32 mm Åndalen 0 - 32 mm Åndalen 22 - 64 mm Hedrum 22 - 64 mm Steinskogen 22 - 64 mm Åndalen 22 - 64 mm Hordaland Resilient modulus (MPa) Figure 4.8:4 Modulus of resilience different materials (Kolisoja 1/1996 and Kolisoja 6/1996). Six different materials were tested in the very large (625 x 1250 mm) repeated load triaxial apparatus at the Norwegian Geotechnical Institute (NGI) and are reported by Vik (1996). These tests also show the differences between gravel and crushed rock materials. For high deviatoric stress levels, the crushed rock is significantly stiffer. Many investigations have addressed the effect of macro and micro roughness of the particles on the deformation behaviour (Cheung 1994, Kolisoja 1997, Thom and Brown 1989). The surface friction angle can be measured using a sliding type test performed by pulling a representative specimen of aggregate loaded on a rough test surface (Cheung 1994). In the test, the horizontal force required to move the aggregate particles that are compressed against the base by a dead load is measured (Figure 4.8:5).
71 Figure 4.8:5 Functional overview of the test arrangment used to measure the surface friction angle of aggregates (Cheung 1994). The surface friction at the contact points of particles can be assumed to affect the resilient deformation behaviour, especially when the external load reaches the value that makes the particles slide. The reason is that the maximum frictional force value resisting sliding is defined as a mathematical product of the coefficient of friction and the normal force acting at the contact point. It should be mentioned that the value of the surface friction angle determined using the friction test as proposed by Cheung (1994) does not necessarily correlate with the visual assessment of the surface roughness. Therefore, the recoverable deformation and the macro level surface roughness do not necessarily interrelate. However, the macro level surface roughness (visible roughness of the individual particles based on the number of protrusions in the surface) probably correlates better with the ability of the material to resist permanent deformations (Thom and Brown 1989, Brown and Selig 1991). The surface structure of mineral crystals probably has more significant influence on the friction, because the surface structure basically determines the micro level influencing mechanisms of the sliding resistance.
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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
Page 22 and 23: 20 σ xx − σ 3 2 det τ yx σ yy
Page 24 and 25: 22 stresses. As it can be seen from
Page 26 and 27: 24 grains. The resistance to partic
Page 28 and 29: 26 The reason was argued to be that
Page 30 and 31: 28 term matric suction implies the
Page 32 and 33: 30 Figure 3.2.1:1 Idealisation of t
Page 34 and 35: 32 ε ε 2 ν = , (Eq. 3.2.2:4) whe
Page 36 and 37: 34 where sij = σ −σ , (Eq. 3.2.
Page 38 and 39: 36 addition, when both the complexi
Page 40 and 41: 38 supplement continuum mechanics m
Page 42 and 43: 40 Figure 4.2:1 A typical variation
Page 44 and 45: 42 Figure 4.2:3 Modulus of resilien
Page 46 and 47: 44 provided that the applied stress
Page 48 and 49: 46 material (Uzan 1985). Dilation i
Page 50 and 51: 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 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 102 and 103: 100 Figure 6.3:1 Effect of loading
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
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120 0,7 0,6 Elastic limit Failure s
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122 Figure 6.8.1:1 Influence of fin
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124 explain why the differences in
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126 was then argued that the variat
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128 7 MODELLING OF PERMANENT DEFORM
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130 Figure 7.2:1 Mohr-Coulomb repre
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132 where K p (N) = bulk modulus wi
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134 1993)) have reported that at le
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136 ε 1,p = accumulated permanent
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138 Barksdale (1972) conducted repe
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140 Figure 7.6:2 Relationship betwe
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142 also be employed for pavement d
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144 repeated loads, although adapta
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146 series of specimens (or in a mu
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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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Liite RHK:n julkaisuun A 5/2006 1 L
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Liite RHK:n julkaisuun A 5/2006 3 2
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RATAHALLINTOKESKUKSEN JULKAISUJA A-
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