1,721,017 research outputs found
Comparison of the measured and computed performance of a propped bored pile retaining wall at Walthamstow
No full textThe impact of climate-related environmental change on the UK solid waste sector
Full text linkThis paper describes the solid waste sector in the UK and its interactions with other parts of the wider UK infrastructure system before exploring the potential effects of climate change and severe weather in the context of the UKCP09 scenarios. There is limited evidence for the direct effects of climate change on the UK solid waste sector. However, it is apparent that much of the disruption to the sector comes from the impact on transport infrastructure. The paper concludes that the biggest climate-related threat to the solid waste sector, as with the UK infrastructure system generally, is flooding due to future increases in winter mean rainfall and peak rainfall events in summer and winter
Landfill as a resource: Issues in environmental science & technology: waste as a resource
No full textOver the past decade or so, the emphasis in Europe and other developed countries has moved from waste to resource management. Re‐usable or recyclable materials are increasingly recovered from the waste stream and organic materials treated prior to landfill; this has resulted in a fundamental change in the nature of the material going to a modern landfill. However, historic landfills remain a potential resource in terms of both materials recovery and the generation of biogas. This chapter assesses the potential benefits of this resource and how it might be exploited, in addition to discussing the engineered controls likely to be needed to prevent pollution of the environment through leakage of leachate into groundwater or the escape of residual biogas from a new landfill containing a more highly processed residual waste
Measuring the contact stiffness at the grain scale of fresh and used granite ballast
No full textFaster, heavier and more frequent use is placing greater demands than ever before on railways. These increased demands reduce the time available for maintenance without costly line closures. There is a need to improve the understanding of the performance of key materials used in railway construction to improve their specification and achieve greater durability. A key material is the source rock for rail-way ballast. It is known that different rock sources perform very differently as ballasts and there is a general consensus that igneous rock types perform the best. However, there can still be great variability in performance between alternate igneous rock ballasts and performance may vary with age/use. To better understand ballast behaviour modern numerical tools such as the discrete element method (DEM) are able to model particles at the grain scale and can be used to assess how changes in ballast material and/or changes in performance with age/use may influence railway performance. However, a lack of understanding of inter-particle ballast contact mechanics mean that current DEM simulations lack the necessary input data to provide a high level of confidence in their outputs. To begin to address this, experiments were carried out to understand the normal contact behavior of fresh and used granite type ballast grains under cycles of load at magnitudes representative of in-service use. The grains were tested using a uniaxial loading machine and the deflections measured using micro-photogrammetry and digital image correlation. The tests indicate significantly different load-deformation characteristics for fresh and used granite ballast and present a method for modelling the contact mechanics modified from Hertzian contact theory. Data also shows that used ballast shows less plastic deformation on first loading and could therefore be potentially re-used in track rather than down-cycled as is currently the case in some countries
Data set for: "The role of stiffness variation in switches and crossings: comparison of vehicle-track interaction models with field measurements"
No full textThis data supports the publication: Grossoni, I., Le Pen, L., Jorge, P., Bezin, Y., Watson, G., Kostovasilis, D., & Powrie, W. (2019). The role of stiffness variation in switches and crossings: comparison of vehicle-track interaction models with field measurements. Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit.
This article/data set is a joint work between the universities of Southampton and Huddersfield. This data set includes the data gathered and processed by University of Southampton. Further data will be available from the University of Huddersfield repository.</span
SWIMS Database input tables and example output results tables
No full textAssigned DOI: 10.5258/SOTON/D0382
Solid Waste Infrastructure Modelling System (SWIMS) complete input and lookup tables for use with NISMOD 1 version of SWIMS.
Complete results for model run 2740 reported within paper entitled "Solid Waste Infrastructure Modelling System (SWIMS): a dynamic optimisation and decision support tool for solid waste infrastructure management".
Model simulation was run within the Newcastle University servers for NISMOD 1 by Jon Coello. details of which are available "Hall, J.W., Tran, M., Hickford, A.J., Nicholls, R.J., 2016. The Future of National Infrastructure: A System-of-Systems Approach. Cambridge University Press."
Data is complete for all 11 GOR of GB.
All LCI data is derived from the Technical University of Denmark (DTU) LCA software EASETECH and should be referenced accordingly when used : "Clavreul, J., Baumeister, H., Christensen, T.H., Damgaard, A., 2014. An environmental assessment system for environmental technologies. Environmental modelling & software 60, 18-30."
Nomenclature:
SW Solid Waste
I Input - standard inputs e.g. area
IO input output file - data required for following years e.g. staged infrastructure builds
LU Look Up - readily editable input file e.g. built facilities
O Output - Main results e.g. CO2e output from waste treatment.</span
Re-engineering the city for sustainable solid waste resource management
No full textThis chapter reviews historic and current waste arisings then, drawing on work carried out under the EPSRC funded SUE waste consortium and the Defra New Technologies Demonstrator Programme for Biodegradable Waste, it assesses current options for waste management within the urban environment, based on the appropriateness of the technology and the scale. Recommendations are made regarding future strategies for urban waste management. The challenges to implementing such a strategy, including retrofitting to existing building stock, are then addressed
Exploring the use of micro-focus computed tomography for a better conceptual understanding of structure in landfilled waste in the context of post-closure management for landfills
No full textAlternative landfill operation strategies are required to reduce the time for which a landfill poses a pollution risk. The application of those alternative strategies, e.g., aeration and flushing, requires recirculation of fluids, consequently their implementation requires better understanding of fluid flow and transport processes in landfills. Research in porous media has revealed that flow and transport processes are strongly controlled by the physical structure, in particular the pore size, geometry and interconnectivity and particle size and shape. It is generally accepted that landfilled municipal solid waste (MSW) develops a heterogeneous and anisotropic structure during placement, degradation and settlement; however our detailed understanding of the structure that develops once MSW is placed into landfills, and how it influences fluid flow is very limited. This paper discusses the use of Micro-Computed Tomography ( CT) for the non invasive study of waste structure. Results are presented for waste analogues which were successfully analysed using threshold segmentation techniques to detect millimetre sized structural features and to quantify the volumetric content of high density materials. Improvements required (e.g., image quality, higher resolution, segmentation techniques) to extend CT to analyse the structure of landfilled waste samples and characterise pore architecture are also discussed
A probabilistic framework for future load carrying capacity estimation of corroded metallic railway bridges under heavy axle weight trains
No full textAssessing the future load carrying capacity (characterised on UK railways by means of a Route Availability number) of historic railway infrastructure under Heavy Axle Weight (HAW) train loads is important for operational and safety reasons. There are, however, considerable difficulties associated with the dual challenges of assessing current condition and potential future rates of degradation. In this paper, a probabilistic assessment framework for estimating future Route Availability (RA) number of ageing metallic railway bridges is proposed. The methodology is demonstrated with reference to a 37.7 m long, single track, three-span, half-through girder, early steel railway bridge. Nonlinear bridge responses to HAW train loads are evaluated using advanced finite-element models accounting for material plasticity, buckling and potential unstable collapse. Possible failure mechanisms were explored using damage measures related to global and localised performance criteria. Ageing of the metallic bridge was modelled assuming that time-dependent non-uniform corrosion dominates the deterioration process. Various model uncertainties, including those governing corrosion, were explicitly accounted for by sampling multiple realisations from a pre-defined multivariate statistical distribution. Future bridge capacity was quantified in the form of Bridge Deterioration Equations (BDEs), i.e., bridge RA number as a function of age and train speed. Derived BDEs suggest that the bridge currently has sufficient capacity, despite nonuniform corrosion to a maximum depth of approximately 3 mm. However, if further deterioration occurs, HAW traffic accessibility could become compromised in three to four decades. The BDE formulation proposed in this paper provides a straightforward piece of information that can be used to support data-driven decision-making processes for both railway infrastructure owners and freight operators
Remediation of mud pumping on a ballasted railway track
No full textMaintenance of ballasted railway tracks is a major cost for railway infrastructure owners. In many developed countries, much of the railway infrastructure is mature and was built for service requirements long since superseded. The increased demands on historic infrastructure can lead to the development or exacerbation of localised trackbed problems that require disproportionate levels of maintenance. Identifying these and applying cost effective remediation has the potential to reduce maintenance spend in the long term. However, it is not always clear what the most cost effective remediation will be. One type of localised maintenance issue is the development of wet beds or wet spots, which can occur where saturated clayey subgrade soils are overloaded and result in the development of mud pumping as trains pass. This leads to the migration of fines into the ballast bed and a deterioration in local track performance. Over time the track overlying the wet bed settles disproportionately more, sleepers become progressively more voided, and train ride quality deteriorates. Maintenance of the wet bed may involve locally digging out and replacing the ballast; however, unless the underlying cause is addressed the problem is likely to recur, requiring repeated localised maintenance interventions. This is costly, reactive and ultimately an ineffective approach to managing the problem. This paper presents a study of a wet bed in the UK, both prior to and after a full track renewal. Transient track deflections during train passage were monitored using sleeper mounted geophones and high speed filming techniques. Loaded track geometry data were obtained from a track recording vehicle. It is shown that local maintenance interventions were generally ineffective, but that a renewal of the top 200 mm of the trackbed including placement of a geotextile filter and geogrid appears to have been successful in remediating the problem, at least in the short term
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