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Significance of flow rule for the passive earth pressure problem (2021)

Schmüdderich, Christoph ; Tschuchnigg, Franz ; Schweiger, Helmut F. ; [weitere]

Springer Berlin Heidelberg

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Publikationsdatum: 2023-09-12

Beschreibung: Determination of earth pressures is one of the fundamental tasks in geotechnical engineering. Although many different methods have been utilized to present passive earth pressure coefficients, the influence of non-associated plasticity on the passive earth pressure problem has not been discussed intensively. In this study, finite-element limit analysis and displacement finite-element analysis are applied for frictional materials. Results are compared with selected data from literature in terms of passive earth pressure coefficients, shape of failure mechanism and robustness of the numerical simulation. The results of this study show that passive earth pressure coefficients determined with an associated flow rule are comparable to the Sokolovski solution. However, comparison with a non-associated flow rule reveals that passive earth pressure coefficients are significantly over predicted when following an associated flow rule. Moreover, this study reveals that computational costs for determination of passive earth pressure are considerably larger following a non-associated flow rule. Additionally, the study shows that numerical instabilities arise and failure surfaces become non-unique. It is shown that this problem may be overcome by applying the approach suggested by Davis (Soil Mech 341–354, 1968).

Beschreibung: Ruhr-Universität Bochum (1007)

Schlagwort(e): ddc:550 ; Finite-element limit analysis ; Finite-element analysis ; Non-associated plasticity ; Passive earth pressure

Sprache: Englisch

Materialart: doc-type:article

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Pure cross-anisotropy for geotechnical elastic potentials (2021)

Niemunis, Andrzej ; Staszewska, Katarzyna ; Niemunis, Andrzej; Institute of Soil Mechanics and Rock Mechanics, Karlsruhe Institute of Technology, Karlsruhe, Germany ; [weitere]

Springer Berlin Heidelberg

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Publikationsdatum: 2023-09-13

Beschreibung: The pure cross-anisotropy is understood as a special scaling of strain (or stress). The scaled tensor is used as an argument in the elastic stiffness (or compliance). Such anisotropy can be overlaid on the top of any elastic stiffness, in particular on one obtained from an elastic potential with its own stress-induced anisotropy. This superposition does not violate the Second Law. The method can be also applied to other functions like plastic potentials or yield surfaces, wherever some cross-anisotropy is desired. The pure cross-anisotropy is described by the sedimentation vector and at most two constants. Scaling with more than two purely anisotropic constants is shown impossible. The formulation was compared with experiments and alternative approaches. Static and dynamic calibration of the pure anisotropy is also discussed. Graphic representation of stiffness with the popular response envelopes requires some enhancement for anisotropy. Several examples are presented. All derivations and examples were accomplished using the algebra program Mathematica.

Beschreibung: Karlsruher Institut für Technologie (KIT) (4220)

Schlagwort(e): ddc:550 ; Cross-anisotropy ; Hyperelasticity ; Inherent anisotropy ; Response envelopes ; Scaling of strain ; Transverse isotropy

Sprache: Englisch

Materialart: doc-type:article

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Quantification of Fracture Roughness by Change Probabilities and Hurst Exponents (2021)

Gutjahr, Tim ; Hale, Sina ; Keller, Karsten ; [weitere]

Springer Berlin Heidelberg

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Publikationsdatum: 2023-08-25

Beschreibung: The objective of the current study is to utilize an innovative method called “change probabilities” for describing fracture roughness. In order to detect and visualize anisotropy of rock joint surfaces, the roughness of one-dimensional profiles taken in different directions is quantified. The central quantifiers, change probabilities, are based on counting monotonic changes in discretizations of a profile. These probabilities, which usually vary with the scale, can be reinterpreted as scale-dependent Hurst exponents. For a large class of Gaussian stochastic processes, change probabilities are shown to be directly related to the classical Hurst exponent, which generalizes a relationship known for fractional Brownian motion. While related to this classical roughness measure, the proposed method is more generally applicable, therefore increasing the flexibility of modeling and investigating surface profiles. In particular, it allows a quick and efficient visualization and detection of roughness anisotropy and scale dependence of roughness.

Beschreibung: Karlsruher Institut für Technologie http://dx.doi.org/10.13039/100009133

Beschreibung: Bundesministerium für Bildung und Forschung http://dx.doi.org/10.13039/501100002347

Schlagwort(e): ddc:550 ; Fracture roughness ; Anisotropy ; Change probability ; Fractional Brownian motion ; Hurst exponent ; Scale dependence ; 60G18 ; 60G15

Sprache: Englisch

Materialart: doc-type:article

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The Di models method: geological 3-D modeling of detrital systems consisting of varying grain fractions to predict the relative lithological variability for a multipurpose usability (2021)

Albarrán-Ordás, Alberto ; Zosseder, Kai ; Albarrán-Ordás, Alberto; Technical University of Munich, Munich, Germany ; [weitere]

Springer Berlin Heidelberg

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Publikationsdatum: 2023-07-29

Beschreibung: The coexistence of a wide variety of subsurface uses in urban areas requires increasingly demanding geological prediction capacities for characterizing the geological heterogeneities at a small-scale. In particular, detrital systems are characterized by the presence of highly varying sediment mixtures which control the non-constant spatial distribution of properties, therefore presenting a crucial aspect for understanding the small-scale spatial variability of physical properties. The proposed methodology uses the lithological descriptions from drilled boreholes and implements sequential indicator simulation to simulate the cumulative frequencies of each lithological class in the whole sediment mixture. The resulting distributions are expressed by a set of voxel models, referred to as Di models. This solution is able to predict the relative amounts of each grain fraction on a cell-by-cell basis and therefore also derive a virtual grain size distribution. Its implementation allows the modeler to flexibly choose both the grain fractions to be modeled and the precision in the relative quantification. The concept of information entropy is adapted as a measure of the disorder state of the clasts mixture, resulting in the concept of “Model Lithological Uniformity,” proposed as a measure of the degree of detrital homogeneity. Moreover, the “Most Uniform Lithological Model” is presented as a distribution of the most prevailing lithologies. This method was tested in the city of Munich (Germany) using a dataset of over 20,000 boreholes, providing a significant step forward in capturing the spatial heterogeneity of detrital systems and addressing model scenarios for applications requiring variable relative amounts of grain fractions.

Beschreibung: Bayerisches Staatsministerium für Umwelt und Verbraucherschutz http://dx.doi.org/10.13039/501100010219

Beschreibung: Technische Universität München (1025)

Schlagwort(e): ddc:550 ; Geological 3-D modeling ; Geostatistics ; Sequential indicator simulation ; Lithological heterogeneity ; Underground management

Sprache: Englisch

Materialart: doc-type:article

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Context aware benchmarking and tuning of a TByte-scale air quality database and web service (2021)

Betancourt, Clara ; Hagemeier, Björn ; Schröder, Sabine ; [weitere]

Springer Berlin Heidelberg

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Publikationsdatum: 2023-08-24

Beschreibung: We present context-aware benchmarking and performance engineering of a mature TByte-scale air quality database system which was created by the Tropospheric Ozone Assessment Report (TOAR) and contains one of the world’s largest collections of near-surface air quality measurements. A special feature of our data service https://join.fz-juelich.de is on-demand processing of several air quality metrics directly from the TOAR database. As a service that is used by more than 350 users of the international air quality research community, our web service must be easily accessible and functionally flexible, while delivering good performance. The current on-demand calculations of air quality metrics outside the database together with the necessary transfer of large volume raw data are identified as the major performance bottleneck. In this study, we therefore explore and benchmark in-database approaches for the statistical processing, which results in performance enhancements of up to 32%.

Beschreibung: H2020 European Research Council https://doi.org/10.13039/100010663

Beschreibung: Forschungszentrum Jülich GmbH (4205)

Beschreibung: https://join.fz-juelich.de/

Schlagwort(e): ddc:550 ; Air quality data ; Scientific database ; Scientific web service ; Performance tests

Sprache: Englisch

Materialart: doc-type:article

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The influence of Antarctic ice loss on polar motion: an assessment based on GRACE and multi-mission satellite altimetry (2021)

Göttl, Franziska ; Groh, Andreas ; Schmidt, Michael ; [weitere]

Springer Berlin Heidelberg

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Publikationsdatum: 2023-11-17

Beschreibung: Increasing ice loss of the Antarctic Ice Sheet (AIS) due to global climate change affects the orientation of the Earth’s spin axis with respect to an Earth-fixed reference system (polar motion). Here the contribution of the decreasing AIS to the excitation of polar motion is quantified from precise time variable gravity field observations of the Gravity Recovery and Climate Experiment (GRACE) and from measurements of the changing ice sheet elevation from altimeter satellites. While the GRACE gravity field models need to be reduced by noise and leakage effects from neighboring subsystems, the ice volume changes observed by satellite altimetry have to be converted into ice mass changes. In this study we investigate how much individual gravimetry and altimetry solutions differ from each other. We show that due to combination of individual solutions systematic and random errors of the data processing can be reduced and the robustness of the geodetic derived AIS polar motion excitations can be increased. We investigate the interannual variability of the Antarctic polar motion excitation functions by means of piecewise linear trends. We find that the long-term behavior of the three ice sheet subregions: EAIS (East Antarctic Ice Sheet), WAIS (West Antarctic Ice Sheet) and APIS (Antarctic Peninsula Ice Sheet) is quite different. While APIS polar motion excitations show no significant interannual variations during the study period 2003-2015, the trend of the WAIS and EAIS polar motion excitations increased in 2006 and again in 2009 while it started slightly to decline in 2013. AIS mass changes explain about 45% of the observed magnitude of the polar motion vector (excluding glacial isosatic adjustment). They cause the pole position vector to drift along 59〈sup〉◦〈/sup〉 East longitude with an amplitude of 2.7 mas/yr. Thus the contribution of the AIS has to be considered to close the budget of the geophysical excitation functions of polar motion.

Beschreibung: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659

Beschreibung: European Space Agency (FR)

Beschreibung: Technische Universität München (1025)

Schlagwort(e): ddc:550 ; Antarctic polar motion excitations ; Combination of GRACE and satellite altimetry data

Sprache: Englisch

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Hans Peter Cornelius (1888–1950): a perfect mapping geologist and scientific explorer of the Alps (2020)

Dullo, Wolf-Christian ; Pfaffl, Fritz A. ; Dullo, Wolf-Christian; GEOMAR Helmholtz Zentrum für Ozeanforschung, Kiel, Germany ; [weitere]

Springer Berlin Heidelberg

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Publikationsdatum: 2023-06-17

Beschreibung: Hans Peter Cornelius was a squeamishly and accurately mapping field geologist with an eye for the finest detail as well as for the large-scale architectural structure of mountain ranges. His excellent work concerned the Rhaetian and Allgäu Alps, South Tyrol, the Valais and Ticino in Switzerland and many regions in Austria. His publications on the Err-Julier Group, the Insubric Line, the Großglockner Group, the Rax-Schneeberg Group, the alpine Grauwackenzone, and the Penninic series of the Western and Eastern Alps became particularly important.

Schlagwort(e): ddc:550 ; Alps ; Mapping ; Profiles ; Tectonics ; Regional geology

Sprache: Englisch

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Geomorphological mapping in the Federal Republic of Germany (2018)

Selbstverl. des Inst. für Phys. Geographie der Freien Univ. Berlin, Berlin

In: Herausgeberexemplar (FU Berlin) | ZB 20559:39

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Publikationsdatum: 2021-03-29

Beschreibung: Contents: LESER, H.: Incorporation of the GMK 25 of the Federal Republic of Germany in the international development of geomorphological maps ; FISCHER, K.: The ”Königssee” sheet of the 1 : 25 000 geomorphological mapping (GMK 25) of the Federal Republic of Germany ; LIEDTKE, H.: Geomorphological Mapping of the scale 1 : 100 000 in the central uplands of the Federal Republic of Germany (GMK 100, sheet 1, C 5510 Neuwied, as an example) ; FRÄNZLE, O.: Assessment of soil parameters for predicting the potential impact of environmental chemicals by means of geo-scientiﬁc maps ; BARSCH, D.: Geomorphic Interpretation of the Geomorphological Map of the Federal Republic of Germany (GMK 25) ; LESER, H. & STÄBLEIN, G.: Legend of the Geomorphological Map 1 : 25 000 (GMK 25) ;

Beschreibung: research

Beschreibung: DFG, SUB Göttingen, FU Berlin

Schlagwort(e): 914 ; 550 ; 910.02 ; Geologische Karte ; Kartierung ; geological map ; Geomorphologie ; cartography ; FID-GEO-DE-7

Sprache: Englisch

Materialart: anthology_digi

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Hydraulic, sedimentological and ecological problems of multifunctional riparian forest management - RIPFOR - (2018)

Selbstverl. des Inst. für Phys. Geographie der Freien Univ. Berlin, Berlin

In: Herausgeberexemplar (FU Berlin) | K 2007 B 398

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Publikationsdatum: 2021-03-29

Beschreibung: PREFACE: The problem of prevention with regard to floodplains is related to two extremes: Prevention of floods and prevention of droughts, both urgent socioeconomic issues during the last years. „Retard the flow of water in the stream corridor“ is the message to cope with both kind of problems. An amphibian landscape will help to maintain water supply during periods of droughts and by its retention area to reduce peaks of high floods. Flood retention areas will function sustainably only if there is an intact ecological system and equilibrium between erosion and accumulation of sediments which in turn both depend from the evolution of the hydraulic conditions and from the succession of the riparian forest. The RipFor — project laid emphasis on the hydraulic processes and their erosion / accumulation effects in retention areas with the aim to get insight into the interaction between riparian vegetation, sediment transport, hydraulics and ecology. Interdisciplinary and intereurOpean work was carried out in the field, the laboratory and by modelling. Results of the RipFor — project as presented in the scientific report and the attached „guidelines for End-Users “ in this way are a contribution to the international discussion on river restoration and to the implementation of the European Water Framework Directives. The scientific report was compiled by Ingo Schnauder and Jens Bölscher (Karlsruhe and Berlin) from contributions of all partners, whereas the bulk of work on the „Guidelines“ was done by Ingo Schnauder (Karlsruhe), Jens Bölscher (Berlin) and Harald Meixner (Vienna), who also cared for the layout. Reporting of the Romanian NAS partner was directed by Virgil Iordache. Assistance of subcontractors and endusers is highly appreciated, especially by Othmar Huppmann (Regierungspräsidium Freiburg / former Gewässerdirektion Oberrhein). Funding within „Quality of Live and Management of Living Resources“ in the RP5 framework of the European Union was essential for this project and is highly acknowledged. Prof. Dr. Peter-Jürgen Ergenzinger

Beschreibung: research

Beschreibung: DFG, SUB Göttingen, FU Berlin

Schlagwort(e): 577 ; 910.02 ; Litoral ; Hydrologie ; Sedimentologie ; Ökologie ; Uferpflanzen ; land-us ; forest management ; ecology ; FID-GEO-DE-7

Sprache: Englisch

Materialart: anthology_digi

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