Tomas M Fernandez-Steeger - Profile on Academia.edu (original) (raw)

Papers by Tomas M Fernandez-Steeger

Sorptive storage of CO2 on coal dust and flotation waste from coal processing in abandoned coal mines

Proceedings of the International Symposium of the International Society for Rock Mechanics, Eurock 2006, Liège, Belgium, 9-12 May 2006, 2006

ABSTRACT

First results in the attempt to adept a Data Mining Strategy for distinguishing global, reginal and local factors reflecting patterns in river water chemistry

Im maschinellen Tunnelbau führen tonige Ausbruchmaterialien in vielen Fällen zu Verklebungen an d... more Im maschinellen Tunnelbau führen tonige Ausbruchmaterialien in vielen Fällen zu Verklebungen an den Metalloberflächen der TBM und insbesondere des Schneidrades. Im Rahmen des Projektes INPROTUNNEL wird versucht, ein besseres Verständnis für die Adhäsionsproblematik zu erlangen.

In der Geotechnik treten bei vielen bautechnischen Prozessen Probleme auf, deren Ursache in Grenz... more In der Geotechnik treten bei vielen bautechnischen Prozessen Probleme auf, deren Ursache in Grenzflächeninteraktionen zwischen Geomaterialien, Werkzeugen oder Werkstoffen begründet ist. So kommt es beispielsweise beim maschinellen Tunnelvortrieb in fein-bis feinstkörnigen Böden und Gesteinen häufig zu einer Adhäsion des Ausbruchmaterials am Schneidrad oder in den Fördereinrichtungen. Dies verursacht große Schwierigkeiten bei Ausbruch, Transport und Wiedereinbau bzw. Deponierung. GEOTECHNOLOGIEN Programms, "TunConstruct" und "SWOP-Semantic Web Based Open Engineering Platform" im 6. EU-Rahmenprogramm. Für den Bereich Additive ist die Fa. CONDAT im Projektverbund zuständig, die seit über 150 Jahren auf dem Gebiet der Schmiermittel und anderer Zusatzstoffe für technische Anwendungen, wie z.B. Konditionierungsmittel für den maschinellen Tunnelbau, tätig ist. Die Firma hat langjährige Erfahrung in der projektspezifischen Auswahl und Anwendung der verschiedensten Konditionierungsmittel und verfügt über ein eigenes Forschungslabor für die Entwicklung "maßgeschneiderter" Produkte. 3 Planung und Ablauf Der Projektbeginn lag im Juli 2008. Zur Erreichung der Ziele im Rahmen dieses Verbundprojekts wurden Arbeitspakete definiert. Jedem Arbeitspaket war ein Projektpartner als Koordinator zugewiesen. Dieser war für die inhaltliche Bearbeitung sowie den rechtzeitigen Abschluss der Arbeitspakete zuständig. Die Verteilung der Verantwortlichkeiten begründete sich aus den Kernkompetenzen der Partner in diesem Verbundprojekt. Die allgemeine Vorgehensweise und Arbeitsplanung waren auf eine Laufzeit des Verbundvorhabens von drei Jahren ausgelegt. Aus den Kernkompetenzen der Projektpartner leitet sich dabei die Struktur des Projekts ab:  Teilprojekt 1: Naturwissenschaftliche Grundlagen (LIH, CIM) Kleinskalige Effekte (nm bis mm), Zusammenhänge im mineralogisch-geologischen Kontext, Manipulation der Mineraloberflächen, Umweltverträglichkeit.  Teilprojekt 2: Ingenieurwissenschaftliche Umsetzung (GIB, HK, ZÜB, CL) Großskalige Zusammenhänge (mm bis m) im geotechnischen und bauverfahrenstechnischen Kontext, geotechnische Eigenschaften vor und nach der Manipulation, tunnelbaupraktische Anwendung.

Untersuchung der Rutschungssuszeptibilität im tektonisch aktiven Hochgebirge mit der InfoVal Methode – eine Fallstudie aus Maily-Say, Kirgistan

Geomorphology, 2015

Close range t-LiDAR Fault plane morphology and alteration Backscatter Pisia fault Corinth 1981 Th... more Close range t-LiDAR Fault plane morphology and alteration Backscatter Pisia fault Corinth 1981 This paper provides a research approach and develops a methodology that helps natural weathered bedrock fault scarps to be understood in terms of their structural changes and backscatter behaviour when using terrestrial laser scanning (t-LiDAR). We tested our approach on the Pisia fault in Greece that ruptured during the 1981 Alkyonides earthquake sequence in Corinth Gulf. The method describes how to correlate fault geometry and structural variations with the backscatter signal of t-LiDAR data from naturally exhumed bedrock fault scarps. Using this method we are able to reconstruct the past slip history. We used t-LiDAR for the analysis of the monochromatic laser beam's backscattered signal to define unsupervised classes of unknown objects on fault surface. Seven classes were created based on the dendrogram technique using the maximum likelihood method. These were used to determine their spatial distribution throughout the scarp height and to calculate the terrain ruggedness index (TRI) in the defined classes. The combination of these results shows that: (i) the ruggedness increases with the scarp height and (ii) the ruggedness and backscattering describe different fault plane conditions. We found evidence for past earthquakes on the Pisia fault at our study site with average displacements in the range of 30-60 cm with corresponding magnitudes of 6.4-6.6 ± 0.1 M S . These results help to reconstruct the recent fault history and potential palaeo-events, and can also be used: i) to detect appropriate sample sites on the fault plane for absolute dating and ii) as an independent constraint on tracing slip events, assisting absolute dating techniques. This method can significantly reduce the sampling requirements and costs of cosmogenic absolute dating techniques. Overall, it might be a valuable tool for extracting data regarding the faulting history and slip events for defining seismic hazard parameters.

Morphotectonics on bedrock scarps on the Island of Crete, Greece

Application of Terrestrial Laser Scanning (T-Lidar) to Characterize the Morphology and Morphotectonics of Bedrock Fault Scarps in Greece

Geoenvironmental Disasters, 2015

The blast-and earth-fill dam of the Kambarata 2 hydropower station is situated in the seismically... more The blast-and earth-fill dam of the Kambarata 2 hydropower station is situated in the seismically active Central Tien Shan region of the Kyrgyz Republic. More than 70% of the dam volume was produced during a blast event on December 22, 2009. In 2010-2011, dam construction was completed after earth filling on top of the blasted material and installing concrete and clay screens together with bentonite grouts. A geophysical survey had been completed in 2012-2013, mainly to monitor the resistivities inside the dam. Results: The geophysical survey completed on the Kambarata 2 dam site showed lower resistivity zones in the earth fill and relatively higher resistivities in the blast-fill material. Topographic, geophysical and piezometric inputs had been compiled within a 3D geomodel constructed with GOCAD software. This model was compared with the design structure of the dam in order to define the upper limits of the underlying alluvium, the deposited blast fill, earth fill and top gravel materials (represented by the dam surface). The central cross-section of this model was extrapolated over the full length of the main dam profile. Conclusions: On the basis of a calibrated hydrogeological model and known geomechanical properties of the materials, dam stability calculations were completed for different scenarios considering different reservoir levels and varying seismic conditions. Some of these scenarios indicated a critical vulnerability of the dam, e.g., if impacted by a horizontal seismic acceleration of Ah = 0.3 g and a vertical seismic acceleration Av = 0.15 g, with an estimated return period of 475 years. As a general conclusion, it was noted that this case study can be used as an example for surveys on much larger naturallandslide or morainedams. A series of geophysical methods (e.g., electrical and electro-magnetic techniques, seismic and microseismic measurements) can be applied to investigate even very deep dam structures. These methods have the advantage over classical direct prospecting techniques, such as drilling, of using equipment that is much lighter and thus more easily transportable and applicable in difficult terrain. Furthermore, they can provide continuous information over wider areas. This specific application to a blast-fill dam allows us to better outline the strengths and weaknesses of the exploration types and geomodels as a series of investigated parameters can be verified more easily than for natural dams.

Landslides and cascading effects on Madeira Island

Heavy rainfall on February 20, 2010 triggered numerous shallow rapid landslides across Madeira Is... more Heavy rainfall on February 20, 2010 triggered numerous shallow rapid landslides across Madeira Island. Most failures started asdebris slides or avalanches at high elevations and transformed into debris flows which rushed downslope into populated coastal areas. The exceptional storm event induced multiple landslide types which show the relations of a cascading effect between preceding landslide processes and triggered successive landslide processes. Cascading effects taken place as large-scale shallow landslides were subsequently channelized into debris flows, which in turn transformed into linked-chains of debris flows by the remobilization of older deposits. The cascading effect continued as channelized debris flows abruptly or transitionally diluted into abrasive hyperconcentrated flows, triggering further slope failures by removal of the lateral support of adjacent slopes. At abrupt changes to low flow velocities and low water-tosediment ratios, hyperconcentrated flows formed tem...

Structural analysis for permeability and stability assessment by use of TLS for the pumped storage hydropower plant Blautal

At present the pumped-storage hydropower plant Blautal is planned with a unsealed lower basin bel... more At present the pumped-storage hydropower plant Blautal is planned with a unsealed lower basin below the groundwater table in a limestone quarry at the southern margin of the Blautal, about 4 Km east of the karst spring Blautopf. The lower basin will be bordered in the east by a steep 95 m high rock face. Due to the high environmental sensibility minimal impact of basin and groundwater level fluctuations to the vicinity is required. To ensure this a detailed geohydraulic and geotechnical rock mass description is essential for modeling. Therefore, terrestrial laser scanning (TLS) was used to map the quarry and subsequently a high resolution digital elevation model (HRDEM) was established. This allows to perform spatial joint analysis with respect to the distribution of geohydraulic and geotechnical properties of the rock mass in the quarry. The results show a high quality and allow a distributed joint analysis and identification as well as projection of major joints in the quarry. Res...

In this paper we explain how the static terrestrial remote sensing method (t-LiDAR) has the poten... more In this paper we explain how the static terrestrial remote sensing method (t-LiDAR) has the potential to support the knowledge of active limestone bedrock fault scarps in defined areas. The focus is on fundamental approaches to analyze fault segments based on 3D data sets. The development of various modular approaches is, therefore, created to determine the relevant information in a neotectonic/paleoseismic context.

Parameterisation of numerical Models for CO2 Storage with Regard to Storage Security during Longwall Mining Operations

During mechanical excavation with a tunnel boring machine (TBM) it is possible that clays stick t... more During mechanical excavation with a tunnel boring machine (TBM) it is possible that clays stick to the cutting wheel and to other metal parts. The resulting delays in the progress of construction work, cause great economic damage and often disputes between the public awarding authorities and executing companies. One of the most important factors to reduce successfully the clay adhesion is the use of special polymers and foams. But why does the clay stick to the metal parts? A first step is to recognize which kind of clay mineralogy shows serious adhesion problems. The mechanical properties of clay and clay suspensions are primarily determined by surface chemistry and charge distribution at the interfaces, which in turn affect the arrangement of the clay structure. As we know, clay is a multi-phase material and its behaviour depends on numerous parameters such as: clay mineralogy, clay fraction, silt fraction, sand fraction, water content, water saturation, Atterberg limits, sticky limit, activity, cation exchange capacity, degree of consolidation and stress state. It is therefore likely that adhesion of clay on steel is also affected by these clay parameters. Samples of clay formations, which caused problems during tunnel driving, will be analyzed in laboratory. Mineralogical analyses (diffractometry, etc.) will be carried out to observe which minerals are responsible for adherence problems. To manipulate the physical properties, batch tests will be carried out in order to eliminate or reduce the adhesion on tool surfaces through variation of the zeta potential.

A palaeostress analysis of an active bedrock normal fault scarp based on kinematic indicators is ... more A palaeostress analysis of an active bedrock normal fault scarp based on kinematic indicators is reconstructed using terrestrial laser scanning (TLS). For this purpose, three key elements are necessary for a defined region: (i) the orientation of the fault plane, (ii) the orientation of the slickenside lineation or other kinematic indicators, and (iii) the sense of motion of the hanging wall. The paper specifies a workflow in order to obtain stress data from point cloud data using terrestrial laser scanning (TLS) in an active tectonic environment. The entire analysis was performed on a continuous limestone bedrock normal fault scarp on the island of Crete, Greece, at four different locations along the WNW-ESE striking Spili Fault. At each location we collected data with the terrestrial light detection and ranging system (t-LiDAR). We then validated the calculated three-dimensional stress results at three of the locations by comparison with conventional methods using data obtained manually with a compass clinometer. Numerous kinematic indicators for normal faulting were discovered on the fault plane surface using t-LiDAR data. When comparing all reconstructed stress data obtained from t-LiDAR to that obtained through manual compass measurements, the degree of fault plane orientation divergence is ±005/03 for dip direction and dip. The degree of slickenside lineation divergence is ±003/03 for dip direction and dip. Therefore, the percentage threshold error of the individual vector angle at each investigation site is lower than 3% for the dip direction and dip for planes, and lower than 6% for the strike. The maximum mean variation of the complete calculated stress tensors is ±005/03.