Anthogalidis A.,TU Darmstadt |
Arslan U.,TU Darmstadt |
Priggert P.,CDM Consult GmbH
Geotechnical Special Publication | Year: 2012
The settlement control of a high-rise warehouse in the Ruhrgebiet, Germany, after partial completion of the raft foundation, is a case history for the efficient use of compaction grouting during ongoing building works. To develop the numerical modeling of compaction grouting, the grouting process in the test area for the high-rise warehouse was simulated through the finite element method. The loading test was simulated through the same finite element model before and after the simulated compaction grouting process. A deformation controlled Eulerian formulation was tested. The calculated ground improvement was compared with the in-situ loading test results. A finite element model for the process of compaction grouting and further for the loading tests on the improved test area was developed. © 2012 American Society of Civil Engineers.
Burbaum U.,CDM Consult GmbH |
Sass I.,TU Darmstadt |
Breuer B.,TU Darmstadt
Geotechnik | Year: 2010
In EPBS tunnel driving, claystones of varying properties causes often serious problems by clogging the TBM. The reason are adhesive forces due to contact of fluids and claystone. The soil sticks on the solid surfaces of the TBM what leads to clogging related to serious delays and increased costs. The adhesion of cohesive soils to solid surfaces depends on the capillary forces of a fluid film inside the soil-solid interface and can be understood as a boundary layer effect. These capillarity forces increase in inverse proportion to the thickness of the fluid film. The surface tension and thickness of fluid film are the main parameters which define the systems properties. This paper addresses the results of research activities on soil-steel surface interactions. Results of adhesion tests using a Lias Alpha claystone example are presented. Consequences for tunnel driving are given.
Sass I.,TU Darmstadt |
Burbaum U.,CDM Consult GmbH
Geotechnik | Year: 2012
In 2007 seven geothermal borehole heat exchangers with a planned depth of 140 m were installed of a small square next to the historic town hall of the City of Staufen for its heating and cooling. Some weeks after completion of the borehole heat exchanger drillings an uplift movement started, causing heavy damages to the surrounding buildings. Officially 269 buildings are currently affected, some are deemed structurally unstable. One office building had to be evacuated. An artesian aquifer was connected hydraulically to the anhydrite bearing Gipskeuper Formation. Anhydrite reacts to gypsum which causes volume extension. The swelling process, once initiated, cannot be stopped easily because the process itself opens and closes water paths. Furthermore Staufen is located on the eastern graben flank of the Upper Rhine Valley on a strongly tectonized massif. Due to these fissured and faulted formations, the prediction of water movement and the swelling process is very difficult. With a newly developed grouting some major cavities near the wellbores were sealed off. This has been partly successful because the maximum uplift rate of about 10 mm/month decreased to less than 4 mm/month (data of May 2012). Additional problems could arise from the good solubility of gypsums in water, which may cause sinkholes. In the last months some small subsidence phenomenon already occurred locally within the uplift area. © 2012 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin.
Lanz J.K.,University of Stuttgart |
Wagner R.,German Aerospace Center |
Wolf U.,Free University of Berlin |
Krochert J.,CDM Consult GmbH |
Neukum G.,Free University of Berlin
Journal of Geophysical Research E: Planets | Year: 2010
We analyzed a small cone field in SW Utopia Planitia that shows striking similarities to volcanic rift zones on Earth. This is of particular interest as the study area lies off any of the volcanic centers of Mars in the northern hemisphere lowlands and is surrounded by material of the Amazonian aged Vastitas Borealis Formation (VBF). We believe that the study area could be the first direct evidence for volcanic activity in Utopia Planitia prior to the resurfacing by VBF material. The most striking characteristics that we observed are (1) a set of broad eruptive fissures showing signs of ongoing extension during cone formation, (2) parallel dike swarms, (3) magmatic intrusions, and (4) a number of lava flows that have erupted from the fissures and pitted cones that surround a larger cone in the center of the study area and that are often associated with, or aligned along, the fissures and dikes. Cratering model ages indicate that the study area is of Late Noachian to Early Hesperian age and is thus distinctly older than the surrounding VBF, falling into the time frame of the main phases of activity in the volcanic centers of Syrtis Major, Elysium Planitia, and the southern highlands. Copyright 2010 by the American Geophysical Union.
Amstaetter K.,University of Tübingen |
Amstaetter K.,CDM Consult GmbH |
Borch T.,Colorado State University |
Kappler A.,University of Tübingen
Geochimica et Cosmochimica Acta | Year: 2012
Microbial reduction of Fe(III) minerals at neutral pH is faced by the problem of electron transfer from the cells to the solid-phase electron acceptor and is thought to require either direct cell-mineral contact, the presence of Fe(III)-chelators or the presence of electron shuttles, e.g. dissolved or solid-phase humic substances (HS). In this study we investigated to which extent the ratio of Pahokee Peat Humic Acids (HA) to ferrihydrite in the presence and absence of phosphate influences rates of Fe(III) reduction by Shewanella oneidensis MR-1 and the identity of the minerals formed. We found that phosphate generally decreased reduction rates by sorption to the ferrihydrite and surface site blocking. In the presence of low ferrihydrite concentrations (5mM), the addition of HA helped to overcome this inhibiting effect by functioning as electron shuttle between cells and the ferrihydrite. In contrast, at high ferrihydrite concentrations (30mM), the addition of HA did not lead to an increase but rather to a decrease in reduction rates. Confocal laser scanning microscopy images and ferrihydrite sedimentation behaviour suggest that the extent of ferrihydrite surface coating by HA influences the aggregation of the ferrihydrite particles and thereby their accessibility for Fe(III)-reducing bacteria. We further conclude that in presence of dissolved HA, iron reduction is stimulated through electron shuttling while in the presence of only sorbed HA, no stimulation by electron shuttling takes place. In presence of phosphate the stimulation effect did not occur until a minimum concentration of 10mg/l of dissolved HA was reached followed by increasing Fe(III) reduction rates up to dissolved HA concentrations of approximately 240mg/l above which the electron shuttling effect ceased. Not only Fe(III) reduction rates but also the mineral products changed in the presence of HA. Sequential extraction, XRD and 57Fe-Mössbauer spectroscopy showed that crystallinity and grain size of the magnetite produced by Fe(III) reduction in the presence of HA is lower than the magnetite produced in the absence of HA. In summary, this study shows that both the concentration of HA and Fe(III) minerals strongly influence microbial Fe(III) reduction rates and the mineralogy of the reduction products. Thus, deviations in iron (hydr)oxide reactivity with changes in aggregation state, such as HA induced ferrihydrite aggregation, need to be considered within natural environments. © 2012 Elsevier Ltd.
Konig D.,Ruhr University Bochum |
Loreck C.,CDM Consult GmbH
Physical Modelling in Geotechnics - Proceedings of the 7th International Conference on Physical Modelling in Geotechnics 2010, ICPMG 2010 | Year: 2010
The installation of diaphragm walls is changing the initial state of stress within the soil. The changes of initial stress in the soil are depending on several factors. One factor is the pressure of the fresh concrete acting within one panel on the soil. An extensive experimental program has been carried out to study the temporary and spatial distribution of the fresh concrete pressure acting within the excavated trench during and just after the concreting process of one panel. This paper is focused on centrifuge tests to study possible silo effects within the concrete column inside of the panel. Also the development of model concretes representing the main characteristics of concretes used in diaphragm wall construction and following the scaling relations is described. © 2010 Taylor & Francis Group, London.
Burbaum U.,CDM Consult GmbH |
Kerr A.G.,CDM Ireland Ltd
2012 Proceedings - North American Tunneling, NAT 2012 | Year: 2012
Dublin City Council (DCC) intends to upgrade the Ringsend wastewater treatment works from its present capacity of 1.64 million population equivalent (PE) to 2.1 million PE to meet the future demand projections for the catchment area and ensure compliance with relevant legislation. The proposed treated final effluent discharge option is to divert the existing inshore effluent discharge point into a purpose built long sea outfall tunnel (LSOT) extension, approximately 5-metre in-internal-diameter and 9-kilometre under Dublin Bay eastwards from the City of Dublin. No geological records existed for the Dublin Bay geology at the project outset. Therefore a marine subsurface investigation, incorporating 21 onshore and offshore boreholes and an inter-tidal geophysics exercise (Marine SI), was completed to determine the geology under Dublin Bay and identify the optimum LSOT tunnel route. The results of the Marine SI radically altered the historically inferred understanding of the bay's geology and have presented a range of complex conditions for tunnel alignment design. This paper will present the methodology and interpretation of results of the Marine SI in Dublin Bay and resulting complexities for the LSOT design.
Wawrzyniak C.,CDM Consult GmbH |
Fromm H.,CDM Consult GmbH
North American Tunneling 2010 Proceedings, NAT 2010 | Year: 2010
This paper deals with the renewal of existing railroad tunnels while maintaining the running railroad traffic. Due to technical reasons of modernization, in Germany many new tunneling projects as well as reconstruction of existing tunnels are underway at present. Depending on tunnel conditions and traffic density, two different construction methods may be applied. In stable ground with moderate rail traffic, the tunnel may be renewed while maintaining the traffic flow. Alternatively a new tunnel may be built next to the existing one. Different methods of ground investigation and design of the tunnel lining for reconstruction of existing tunnels are described.
Wawrzyniak C.,CDM Consult GmbH
Proceedings - Rapid Excavation and Tunneling Conference | Year: 2011
High-speed rail is emerging in Europe as an increasingly popular and efficient means of transport. The first high-speed rail lines in Europe built in the 1980s and 1990s, improved travel times on intra-national corridors. Since then, several countries have built extensive high-speed networks, and there are now several cross-border high-speed rail links. In Germany a huge number of high-speed railway links is completed and is in operation. To strengthen the network as a whole a number of lines is still under design and under construction. The speeds vary, from 250 km/h to 280 km/h. Later lines are passed for service speeds of 300 km/h. The third generation of the Inter-City-Express (ICE) trains has a service speed of 330 km/h and has reached speeds up to 360 km/h. This presentation looks at the technical challenges faced when designing the tunnels of the high-speed rail lines from Cologne to Frankfurt and from Stuttgart to Ulm as well as inner-city rail links like the City Tunnel Leipzig.
Jaenig F.,CDM Consult GmbH
WIT Transactions on Ecology and the Environment | Year: 2012
The hydrothermal ore deposits of the Harz region have fostered an early development of metal ore mining and the closely linked metallurgy. In the closer Harz region and its proximate foreland the soils are highly enriched with heavy metals due to the emissions of the metallurgy. Through leaching processes and fluvial transport, these particles are enriched in river basins of Oker, Innerste, Leine, and Aller in the form of watery solutions or bound to suspended particles (so-called the "Harz-problem"). Floodwater events of these rivers lead to sedimentation in the wet lands, which partially show high concentrations of heavy metals - especially, arsenic, cadmium, copper, lead and zinc. Concentrations, which limit the human usage of these soils and waters, are common. For a consistent record and assessment of the contaminated areas by heavy metal a field mapping with regard to usage and a probing concept of the affected river area was created. On this basis a declaration of areas with equal heavy metal potentials and an assessment of the areas with regard to an action plan was carried out. © 201 WIT Press.