Bestimmung der Kontamination von Tunnelausbruchmaterial durch Sprengmittel und Dieselmotoremissionen im konventionellen Vortrieb

This thesis investigates the contamination of tunnel excavation material produced due to conventional tunneling is investigated. The focus lies on potential pollutant inputs originating from explosives as well as from diesel engine emissions. The background of this study is the increasing importance of reusing excavated material and the associated necessity to comply with legal limit values. While it was previously assumed that the contamination of the muck with nitrogen compounds such as ammonium, nitrate and nitrite results predominantly from the use of explosives, new observations indicate that diesel engines of construction machinery and vehicles can also make a significant contribution to this type of contamination. These emissions likewise contain nitrogen oxides and unburned hydrocarbons, which may deposit on the muck and complicate a clear attribution of the pollutant source. In order to answer the research question, an extensive literature review was realized, with particular emphasis on identifying the relevant limitation values for the reuse of tunnel excavation material. Subsequently, datasets from an already existing study as well as newly obtained samples were compared with these values. The samples are taken from mechanical excavation, drill and blast excavation and an underground mining operation, allowing therefore a comprehensive assessment of the influence of diesel engine emissions. The results show that emissions from diesel engines often have a greater impact on the contamination of the muck than explosives. The correlation analysis carried out in this thesis further confirms a positive relationship between diesel related indicators and nitrogen compounds. Overall, the findings demonstrate that attributing the contamination to a single source is complex and cannot always be determined clearly. However, the results show that explosives should not be regarded as the sole cause of contamination in the muck, as diesel engine emissions represent a significant and so far underestimated pathway of pollutant input.