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  • 1.
    Asplund, Anette
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering - Swedish Blasting Research Centre.
    Avvattningens påverkan på spårläget2017Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The aim of this work is to investigate the relationship between the dewatering measures and the condition of the track quality and whether dewatering affect the degradation rate of the track. The goal is to find out if the dewatering of the substructure gives a better track quality condition and a slower track degradation. The literature study performed in this work shows that there is no research done that demonstrates the relationship between dewatering and track quality degradation.

    This work comprise a case study of railway lines where dewatering has been performed compared to sections with the same properties were dewatering was not performed. The work is limited to the track section 113 and 124, and to investigation of the height deviation of the track. The Swedish Transport Administration, Trafikverket, has made data available from the database OPTRAM which is used in the analysis. Three different wave length were analysed; short-wave (1-25 m), medium-wave (25-70 m) and long-wave (70-150 m). This is a quantitative study limited to literary studies, data collection, data quality assessment and data analysis. The results have been analysed by means of literature studies including newly published results from this field.

    The dewatering measures gives following effects in the studied wavelengths:

    • The dewatering impact on the track quality in all wavelengths.
    • The dewatering initially impairs track quality in the short-wave which may be caused due to settlements in the substructure.
    • The track quality in the medium-wave show an improvement of the track quality, which are statistical confidentially.
    • The track quality in the long-wave show a marginal changes after the dewatering.
    • The degradation rate of the track quality for the medium-wave will be lower after dewatering, which applies to both the time and tonnage domain.
    • To compensate the change in the track quality after dewatering for the short-wave the recommendation is to tamp the track after dewatering.

    This study shows that dewatering of the substructure followed by tamping is a good maintenance action to improve the track quality in the long-time run. Today Trafikverket primarily use the short-wave to initiate the maintenance activity tamping, however it is a point to look more even on the medium-wave to get a more holistic view of the track quality and its degradation.

    Further work could be to analyse more number of sections that had have problems with track quality and were no tamping is done before dewatering but could have been done in combination with dewatering. Tamping can have been performed after one or a couple of year after dewatering. Moreover, further work could be to develop a cost model for dewatering in a lifecycle perspective.

  • 2.
    Mohammad, Mohammad E.
    et al.
    Department Dams and Water Resources Engineering, University of Mosul.
    Al-Ansari, Nadhir
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering - Swedish Blasting Research Centre.
    Issa, Issa E.
    Knutsson, Sven
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Sediment in Mosul Dam reservoir using the HEC-RAS model: Sediment in Mosul Dam reservoir using the HEC-RAS model2016In: Lakes & Reservoirs: Research and Management, ISSN 1320-5331, E-ISSN 1440-1770, Vol. 21, no 3, p. 235-244Article in journal (Refereed)
    Abstract [en]

    Mosul Dam, located on the Tigris River north of Iraq, is experiencing sedimentation problems, especially near the Al-Jazeera pumping station that supplies the irrigation water for the Al-Jazeera project. The sources of the sediment accumulated within the reservoir are from the Tigris River, as well as ten side valleys on both sides of the reservoir. The sediment inflow rate into the reservoir and the released values are considered on the basis of the operation schedule of the dam for the considered period from 1986 to 2011. The sediment loads were estimated on the basis of available measurements and estimated literature values. The HEC-RAS 4.1 model was used for flows and sediments in the main river and  reservoir. The model was calibrated for flow simulations (coefficient of determination r2 = 0.87) and sediment routing based on bed level, (with resultant r2 = 0.98 and Mean Absolute Deviation of 0.95). The Ackers–White equation was used in the HEC-RAS model for sediment routing because of the wide range of sediment sizes in the study case. The resultant total accumulated sediment load volume was 1.13 km3, a value that is very close to the measured values (1.143 km3) obtained from a previous bathymetric survey. Furthermore, the model indicated most of the sediment (80.7%) was deposited during the first five of the dam operation.

  • 3.
    van Eldert, Jeroen
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering. Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering - Swedish Blasting Research Centre.
    Schunnesson, Håkan
    Johansson, Daniel
    Saiang, David
    Measurement While Drilling (MWD) technology for blasting damage calculation2018In: 12th International Symposium on Rock Fragmentation by Blasting, Luleå Sweden 11-13 June 2018 / [ed] Håkan Schunnesson, Daniel Johansson, 2018Conference paper (Refereed)
  • 4.
    van Eldert, Jeroen
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering. Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering - Swedish Blasting Research Centre.
    Schunnesson, Håkan
    Johansson, Daniel
    Saiang, David
    Measurement While Drilling to Predict Rock Mass Quality and SupportManuscript (preprint) (Other academic)
    Abstract [en]

    A tunnelling project is normally initiated with a site investigation to determine the in-situ rock mass conditions and to generate the basis for the tunnel design and rock support. However, since site investigations often are based on limited information (surface mapping, geophysical profiles, few bore-holes, etc.), the estimation of the rock mass conditions may contain inaccuracies, resulting in underestimating the required rock support. The study hypothesised that these inaccuracies could be reduced by using Measurement While Drilling (MWD) technology to assist in the decision-making process. A case study of two tunnels in the Stockholm bypass found the rock mass quality was severely overestimated by the site investigation; more than 45% of the investigated sections had a lower rock mass quality than expected. MWD data were recorded in 25m grout holes and 6m blast holes. The MWD data were normalised so that the long grout holes with larger hole diameters and the shorter blast holes with smaller hole diameters gave similar results. With normalised MWD data, it was possible to mimic the tunnel contour mapping; results showed good correlation with mapped Q-value and installed rock support. MWD technology can improve the accuracy of forecasting the rock mass ahead of the face. It can bridge the information gap between the early, somewhat uncertain geotechnical site investigation and the geological mapping done after excavation to optimise rock support.

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