Deformation behaviour of railway embankment ... - Liikennevirasto

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158 particles. During the test, the latex membrane was pressed into the gaps and punctured due to over-stretching. A thicker, neoprene membrane was therefore used as the outer membrane and found to be quite satisfactory. 8.6.3 Repeated load triaxial tests by Werkmeister (2003) In her investigations, Werkmaister used CCP-type repeated load triaxial tests and measured only the vertical deformations, because the system to measure the radial deformations was found not to be reliable. Furthermore fixing the hoops was occasionally found to disturb the studs. For the repeated load triaxial tests the constant confining pressure (applied via pneumatic pressure) was set at levels of 70, 140, 210, and 280 kPa. After the confining pressure had been reached, additional dynamic (frequency = 5 Hz) vertical stress (deviator stress) pulses were applied. The repeated load triaxial tests were carried out with axial stress pulses having stress ratios (σ D / σ c ) from 0.5 to 1 l. Figure 8.6.3:1 shows the test stress paths for the repeated load triaxial testing. Figure 8.6.3:1 Stress paths (Werkmeister 2003). Half sine load pulses were applied to the test specimens with each load cycle consisting of a 50 % loading phase followed by a 50 % neutral phase (Figure 8.6.3:2). To define the peaks exactly, 80 reading points were measured (64 reading points during the loading phase and 16 reading points during the neutral phase).
159 Figure 8.6.3:2 Phases of a load cycle (Werkmeister 2003). The total strains consisted of three parts: hydrostatic strains (permanent), resilient strains, and permanent strains (Figure 8.6.3:3). Figure 8.6.3:3 Components of strain (Werkmeister 2003). The permanent hydrostatic strain part was not considered, because the magnitudes of these strains were too low for an accurate measurement. A computer with the control software ATS (Automated Testing System) was used to register the test measurements (vertical deformations) and other test parameters such as the number of load cycles, time, confining pressure, and deviatoric stress. However, the analysis of the test results was not carried out by this ATS software, because it takes the peaks of the deformation line as the basis of the test results. Instead, the analysis method adopted by Werkmeister in her investigation was developed by Kiehne (2001). This
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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
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50 The grain size distribution of g
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52 The grain sizes that determine t
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54 4.6.3 Fines content A simple cha
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56 grained than for fine-grained ag
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58 and the shape of the particles a
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60 Figure 4.7:1 Effect of the wetti
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62 Figure 4.7:3 Modulus of resilien
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64 Figure 4.7:6 Dry -density as a f
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66 Figure 4.7:7 Resilient response
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68 The form index can be measured u
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70 Hovinmoen are gravel materials.
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72 5 MODELLING OF RESILIENT DEFORMA
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74 5.2.2 Resilient modulus as a fun
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76 M r k2 k3 ⎛ θ ⎞ ⎛ q ⎞ =
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78 the model showed good representa
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80 discussed. However it can be exp
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82 et al. (2003) calculated the res
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84 p u = unit pressure (1 kPa), δp
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86 Figure 5.2.5:2 Vertical resilien
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88 2 1 ⎛ ⎞ = A q ε ν p ⎜1
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90 Figure 5.3:2 An example of the c
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92 by incorporating a coefficient o
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94 6 FACTORS AFFECTING PERMANENT DE
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96 cycles. He drew the general conc
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98 accumulated strain, ε p , is co
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100 Figure 6.3:1 Effect of loading
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102 load” is not equal to the fai
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104 Chan (1990) noticed, in his stu
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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
Page 152 and 153: 150 In conclusion, both Huurman (19
Page 154 and 155: 152 aim to simulate as closely as p
Page 156 and 157: 154 by the American Association of
Page 158 and 159: 156 Confining pressure is applied t
Page 162 and 163: 160 method takes the average value
Page 164 and 165: 162 Figure 8.7.2:2 Schematic illust
Page 166 and 167: 164 through each platen is provided
Page 168 and 169: 166 measured for the 600 mm central
Page 170 and 171: 168 displayed on the monitor in gra
Page 172 and 173: 170 unbound granular materials. The
Page 174 and 175: 172 Figure 8.8.2:2 Permanent axial
Page 176 and 177: 174 performance-related (functional
Page 178 and 179: 176 the six supports of the vertica
Page 180 and 181: 178 under the same isotropic stress
Page 182 and 183: 180 9 CONCLUSIONS 9.1 Resilient def
Page 184 and 185: 182 − Permanent deformation resis
Page 186 and 187: 184 Balay J., Gomes Correia A., Jou
Page 188 and 189: 186 Cheung, L.W. (1994). Laboratory
Page 190 and 191: 188 El abd, A., Hornych, P., Breyss
Page 192 and 193: 190 Hoff, I., Nordal, S., and Norda
Page 194 and 195: 192 Kolisoja, P. (1996b) Large Scal
Page 196 and 197: 194 Mitry, F.G. (1964). Determinati
Page 198 and 199: 196 Plaistow, N.C. (1994). Non-Line
Page 200 and 201: 198 Tam, W.A. and Brown, S.F. (1988
Page 202 and 203: 200 Wellner, F. (1996). Influence o
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