Browsing by Author "McDowell, G. R."
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Item Metadata only The application of Weibull statistics to the strength of railway ballast(2004) Lim, W. L.; McDowell, G. R.; Collop, AndyItem Metadata only Comparison of ballast index tests for railway trackbeds(2004) McDowell, G. R.; Lim, W. L.; Collop, Andy; Armitage, R. J.; Thom, N. H.Item Metadata only Cyclic loading of railway ballast under triaxial conditions and in a railway test facility(Springer, 2009) McDowell, G. R.; Aursudkij, B.; Collop, AndyA recently developed large-scale triaxial test apparatus for railway ballast testing comprises a double-cell arrangement for measuring volume change by differential pressure. Monotonic and cyclic tests were performed on limestone ballast samples. Axial and volumetric strains and breakage were determined from both types of test. Resilient modulus and Poisson’s ratio were obtained only from the cyclic tests. The permanent axial strain and breakage results from the cyclic tests are compared with the simulated traffic loading in the railway test facility (RTF) which comprises three sleepers embedded in ballast over a subgrade. The traffic loading in the RTF was applied by hydraulic actuators with built-in displacement transducers. A column of painted ballast was placed under a rail seat of the middle sleeper to ease sample collection for sieve analysis at the end of the test. The stress condition in the RTF is predicted by a simple calculation based on findings of previous literature. It was found that the results from the cyclic triaxial test with conditions similar to the predicted conditions in the RTF were comparable to those results from the RTF tests.Item Metadata only A dimensional analysis of scaling viscosity and velocity in DEM of constant strain rate tests on asphalt(2009) McDowell, G. R.; Collop, Andy; Wu, J.Item Metadata only Discrete Element Modelling of Constant Strain Rate Compression Tests on an Idealised Asphalt Mixture(2011) Wu, J.; Collop, Andy; McDowell, G. R.Item Metadata only Discrete Element Modelling of Low Temperature Monotonic Compression Tests in an Idealised Asphalt Mixture(2008) Wu, J.; Collop, Andy; McDowell, G. R.Item Metadata only Discrete Element Modelling of Monotonic Compression Tests in an Idealised Asphalt Mixture(2009) Wu, J.; Collop, Andy; McDowell, G. R.Item Metadata only Laboraratory simulation of the effects of train loading and tamping on ballast(2005) McDowell, G. R.; Lim, W. L.; Collop, Andy; Armitage, R. J.; Thom, N. H.Item Metadata only Measuring the strength of railway ballast(2003) McDowell, G. R.; Lim, W. L.; Collop, AndyItem Metadata only Micro mechanics of railway ballast degradation(2002) McDowell, G. R.; Lim, W.L.; Collop, Andy; Brown, S. F.Item Metadata only Modelling dilation in an idealised asphalt mixture using discrete element modelling(2006) Collop, Andy; McDowell, G. R.; Lee, Y.Item Metadata only Modelling the behaviour of an idealised asphalt mixture using the distinct element method.(2004) Collop, Andy; McDowell, G. R.; Lee, Y.Item Metadata only On the use of Discrete Element Modelling to simulate the viscoelastic deformation behaviour of an idealised asphalt mixture(2007) Collop, Andy; McDowell, G. R.; Lee, Y.Item Metadata only Quantifying the relative strengths of railway ballasts(2005) Lim, W. L.; McDowell, G. R.; Collop, AndyItem Metadata only Student-centered learning in pavement and geotechnical engineering(2000) McDowell, G. R.; Collop, AndyItem Metadata only Use of the distinct element method to model the deformation behaviour of an idealised asphalt mixture.(2004) Collop, Andy; McDowell, G. R.; Lee, Y.