Fault induced permanent ground deformations: Experimental verification of wet and dry soil, numerical findings’ relation to field observations of tunnel damage and implications for design     

Jrgen Johansson  Kazuo Konagai 《Soil Dynamics and Earthquake Engineering》2007,27(10):938-956

Few building codes contains provisions fault surface ruptures and accompanying soil deformations which constitutes a great risk to human lives, buildings and infrastructure. A numerical and experimental comparison show a fair agreement of result. Analysis of “real” scale show the how water increases the incompressibility of wet soil causing shear deformations to become larger and conjugate ruptures to appear for reverse faults. Field observations and numerical analysis indicates that horizontal compression of soil surrounding underground structures should be taken into account in design.  相似文献   

Direct effects of Daphnia-grazing, not infochemicals, mediate a shift towards large inedible colonies of the gelatinous green alga Sphaerocystis schroeteri     

Heike Kampe  Marie König-Rinke  Jürgen Benndorf 《Limnologica》2007,37(2):137-145

The influence of Daphnia galeata×hyalina grazing and of infochemicals released by the daphnids on the colony size and growth rate of the colonial gelatinous green alga Sphaerocystis schroeteri (Chlorococcales) was investigated in laboratory batch experiments run for 96 h. High zooplankton grazing pressure was exerted by a final concentration of 100 daphnids L⁻¹ in the Daphnia treatments. Infochemicals were obtained by filtration (0.2 μm) of water from D. galeata×hyalina cultures (200 ind. L⁻¹ exposed for 24 h). This filtrate was added to the S. schroeteri cultures in two concentrations corresponding to 7 and 50 daphnids L⁻¹, respectively. The growth rate of S. schroeteri was neither affected significantly by direct Daphnia grazing nor by the presence of Daphnia infochemicals, in comparison to the control. However, the portion of inedible S. schroeteri colonies (diameter>50 μm) increased under direct grazing pressure, whereas the Daphnia infochemicals did not influence the colony size significantly. We conclude that the shift in colony size by direct zooplankton grazing denotes an effective defence mechanism against size selective feeding for colonial gelatinous green algae. This effective defence in combination with unchanged growth rates of the larger colonies (under non-limiting nutrient and light conditions) falsifies the assumption of a trade-off between minimising grazing losses and maximising growth by optimising the colony size.  相似文献   

Continuous,Direct Gas-Geochemical Monitoring in Hydrothermal Vents: Installation and Long-Term Operation on Nisyros Island (Greece)     

Manfred Teschner  Eckhard Faber  Jürgen Poggenburg  Georgios E. Vougioukalakis  Georgios Hatziyannis 《Pure and Applied Geophysics》2007,164(12):2549-2571

In this paper the installation and long-term operation of a system for continuous monitoring of fumarolic gases is described. Several physicochemical and gas-geochemical parameters such as the concentration of CO₂, H₂S and CO in the fumarolic emissions, as well as the temperatures of the hydrothermal steam and soil in close vicinity of the fumarole and steam pressure are measured in short-time intervals (typically 15 seconds). Data are logged on-site and in parallel transferred to a remote station by digital telemetry. Specially developed software enables the real-time observation of the local conditions in the crater and full bidirectional control of the monitoring system. Fluctuations in the monitored parameters are also reported. From the data presented it can be concluded that environmental conditions (direction and strength of wind, precipitation) will interact with some of the parameters monitored. These influences can only be revealed by continuously operated monitoring systems.  相似文献   

Desalinization of running waters: III. Changes in the structure of diatom assemblages caused by a decreasing salt load and changing ion spectra in the river Wipper (Thuringia, Germany)     

Horst Ziemann  Ludwig Kies  Claus-Jürgen Schulz   《Limnologica》2001,31(4):257-280

Salt-loaded effluents were introduced into the river Wipper during the mining period for almost a century. Beginning with the year 1990, the waste water load was strongly reduced due to the termination of the potash industry. Prior to 1990, monthly means of the chloride concentrations at times exceeded 6,000 mg l⁻¹ in the strongly polluted sections. Maximum concentrations reached twice these values. Up to 1998, mean annual chloride concentrations decreased to values below 2,000 mg l⁻¹. This led to more balanced fluctuations in salinity which had been pronounced before, depending on discharge and short-term changes in production. Similarly, the physiologically adverse ion conditions improved due to decrasing potassium and increasing calcium proportions.

In 1963/64, 1986 and 1998, samples of epilithic, epiphytic and epipsammic diatoms were taken at locations of different salinities along the river and examined for the effects of the salinization on the structure of the diatom assemblages. These structures changed in dependence on salinity. Increasing salt concentrations coincided with decreasing oligohalophilic and increasing mesohalophilic and polyhalophilic species numbers. Above a chloride concentration of about 3,000 mg l⁻¹, the proportion of the latter exceed that of the former (halobion index > 50). Corresponding to different conditions of salinization along the river, characteristic diatom assemblages occur differring from each other and which are specific for the river section. Spring and autumn aspects of the diatom assemblages show also salt-dependent differences. The assemblages found in 1998 after decrease of salinization have changed markedly in comparison to those from 1963/64 and 1986. Halobiontic species predominating formerly occurred only occasionally or not at all. They were replaced by oligohalobic-indifferent forms.

An ecological assessment of the changes was performed based on the halobion index calculated from all the samples. For the strongly salinized section of the river Wipper, a shift from -mesohalobic/polyhalobic conditions in 1963/64 and 1986 to -oligohalobic/β-mesohalobic conditions in 1998 was found. However, constant -oligohalobic conditions are still not given. With regard to the transition from -oligohalobic (limnetic) to β-mesohalobic (brackish) conditions, a maximum chloride concentration of 600 mg l⁻¹ was found. To guarantee -oligohalobic conditions, a maximum chloride concentration of 400 mg l⁻¹ should not be exceeded.  相似文献   

Auswirkungen des Ablassens von Hochwasserrückhaltebecken auf deren Limnochemie und Phytoplankton-Biozönose     

Susanne Maier  Klaus Zintz  Jürgen Bhmer  Petra Sterk  Hinrich Rahmann 《Limnologica》2001,31(3):239

Reservoirs have to be released when repairing of the dams is necessary. In 1995, two reservoirs in Baden-Württemberg (Germany) of similar age and volume (Lake Herrenbach near Göppingen, 1.0 Mio. m³ and Lake Breitenau near Heilbronn, 2.3 Mio. m³) were emptied. This allowed the singular possibility to investigate the effects of drainage and refilling on the limnochemistry and the phytoplankton biocoenosis of such artificial lakes.Before the drainage of the reservoirs, both lakes showed phosphorus release from the sediment during summer stagnation. Phosphorus values of Lake Herrenbach were regularly higher than those of Lake Breitenau (Lake Herrenbach 88 μg/l, Lake Breitenau 33 μg/l). During release, both lakes indicated higher phosphorus and chlorophyll concentrations as well as rising biomasses. Remarkable differences were observed during refilling of the reservoirs: while Lake Herrenbach showed higher transparency and lower phosphorus concentrations, Lake Breitenau progressed towards eutrophication (total phosphorus during summer 1996: Lake Herrenbach 30 μg/l, Lake Breitenau 55 μg/l). One reason for the reaction of Lake Breitenau was the reduced ground drainage during the refilling, which caused an accumulation of nutrients in the hypolimnion. Another reason was the mineralisation of vegetation which covered great parts of the dry lake sediment. The limnological change of Lake Herrenbach was not as clear but could be caused by the restauration of the pre-reservoir which was drainaged and dredged before the emptying of the main reservoir started as well as many other facts which differed Lake Herrenbach from Lake Breitenau.  相似文献   

The Middle Jurassic radiolarites and pelagic limestones of the Nieves unit (Rondaide Complex, Betic Cordillera): basin starvation in a rifted marginal slope of the western Tethys     

Luis O'Dogherty  Agustín Martín-Algarra  Hans-Jürgen Gursky  Roque Aguado 《International Journal of Earth Sciences》2001,90(4):831-846

Middle Jurassic radiolarites and associated pelagic limestones occur in the Rondaide Nieves unit of the Betic Cordillera, southern Spain. The Rondaide Mesozoic includes: (a) a thick succession of Triassic platform carbonates, comparable to the Alpine Hauptdolomit and Kössen facies; (b) Lower Jurassic pelagic limestones comparable to the Alpine Hierlatz and Adnet facies; (c) the Middle Jurassic Parauta Radiolarite Formation, described herein; and (d) a thin Upper Jurassic-Cretaceous condensed limestone succession. The Parauta Radiolarite Formation and associated limestones were studied with respect to stratigraphy, petrography, micropalaeontology (radiolarians, calcareous nanno- and microfossils) and facies. Radiolarite sedimentation occurred in the Middle Bathonian in a restricted and dysoxic deep Nieves basin, perched in the distal zone of a continental margin fringing the Tethyan ocean. This margin was adjacent to a young narrow oceanic basin between the South-Iberian margin and a continental block called Mesomediterranean Terrane. The Nieves basin was part of a marine corridor between the Proto-Atlantic and Piedmont-Ligurian basins of the Alpine Tethys. The regional tectonic position, the stratigraphical evolution since the Triassic, the age and the nature of the Mesozoic facies and the palaeogeographic relations to adjacent domains show striking analogies between the Betic Rondaide margin and coeval units of the Alps.  相似文献   

Climatic change and design criteria in water resources management a regional case study     

Gerd Frch  Friedhelm Garbe  Jürgen Jensen 《Atmospheric Research》1996,42(1-4)

As a result of the anthropogenic greenhouse effect there is fear of alterations of the world climate, which also may result in hydrological changes and consequently in water resources management. In a case study it was investigated if such changes could be identified for a regional catchment area. Summarized it may be said that the regional analysis of hydro-meteorological data in the catchment area of the Sieg showed the expected effects of the anthropogenic climate change on the regional water cycle. Rises in annual mean temperature and precipitation could be observed over a period from 1892 until 1993. However, a significant relation between evident changes and greenhouse effect could not be stated. Changes in discharge do not show consistent behavior. Especially apparent contradictions show that additional examinations are necessary in order to make the complex natural inter-relationships between climate and regional water cycle with the impacts of existing anthropogenetic interferences visible and applicable for practical engineering tasks.  相似文献   

Decadal variability on the northwest european shelf     

Jürgen Sündermann  Gerd Becker  Peter Damm  Dries van den Eynde  Alexander Frohse  Remi Laane  Wim van Leussen  Thomas Pohlmann  Wim van Raaphorst  Günther Radach  Helga Schultz  Marijke Visser 《Ocean Dynamics》1996,48(3-4):365-400

  相似文献   

Empirische Untersuchung zur Frage der Beziehung zwischen durchschnittlicher und kennzeichnender Wellenperiode im Seegang     

Piest  Jürgen 《Ocean Dynamics》1963,16(1):9-14

Zusammenfassung Als Zusammenhang zwischen der kennzeichnenden Wellenperiode und der durchschnittlichen Periode im Seegang wird die Formel angesetzt. Mit Hilfe empirischer Unterlagen wird nachgewiesen, daßc eine Funktion des von D. E. Cartwright und M. S. Longuet-Higgins [1956] eingeführten Spektralparameters ist. Es wird eine vorläufige quantitative Beziehung zwischenc und abgeleitet.

---

Empirical investigations of the relation between the mean and the significant wave period in the sea

Summary It is supposed that the formula represents the relation between the significant wave period and the mean period in the sea. With the aid of empirical data it is demonstrated thatc is a function of the spectral parameter introduced by D. E. Cartwright and M. S. Longuet-Higgins [1956]. A preliminary quantitative relation betweenc and is derived.

---

Etudes empiriques de la relation entre la période moyenne et la période significative des vagues dans la houle

Résumé On suppose que la formule représente la relation entre la période significative des vagues et la période moyenne dans la houle. A l'aide des données empiriques on montre quec est une fonction du paramètre spectral , introduit par D. E. Cartwright et M. S. Longuet-Higgins [1956]. Une relation quantitative préliminaire entrec et est dérivée.

---

  相似文献   

Mathematische Simulation ptygmatischer Strukturen     

Dozent Dr.-Ing. Hansgeorg Förster  Dipl.-Ing. Jürgen Leonhardt 《International Journal of Earth Sciences》1972,61(3):883-896

Zusammenfassung Die Entstehung der Schlingen in den südlichen Ötztaler Alpen (Ostalpen) wurde bisher überwiegend auf äußere Spannungsfelder zurückgeführt. Damit waren die Faltenstrukturen in diesem Gebiet durch Biege- und Biege-Scher-Faltung hinreichend erklärbar. Bei Berücksichtigung der hohen Teilbeweglichkeit des Gesteins während der Schlingenbildung muß ein anderer Faltungsmechanismus angenommen werden. Es wird versucht, die Faltenstrukturen als Ergebnis eines Fließvorgangs in Abhängigkeit von einer Geschwindigkeitsverteilung zu erklären. Unter Benutzung eines vonHarburgh &Bonham-Carter entwickelten Programms und bei Vorgabe verschiedener Randbedingungen werden Strombilder simuliert und vom Plotter in Geschwindigkeits-Vektor-Darstellung ausgegeben. Die Ergebnisse werden im Gelände beobachteten Strukturen und im Experiment erzeugten Bildern gegenübergestellt. Die gute Übereinstimmung kann als Hinweis auf die Entstehung ptygmatischer Strukturen durch interne Geschwindigkeitsverteilung angesehen werden.

---

Until now the formation of vortex structures in the southern Oetztal Alps (Eastern Alps) has been regarded as the result of external stresses, allowing adequately to explain the structures as flexural and passive folds. Taking into consideration the high ductility of rocks during vortex formation another mechanism of folding has to be assumed. The attempt is made to explain the structures as the result of flowage due to a velocity distribution. Using a programm written byHarburgh &Bonham-Carter arrays of stream lines are calculated for varying boundary conditions and plotted as velocity vectors. The output will be compared with structures observed in the field as well as with results of folding experiments. From the good agreement follows that ptygmatic folding may be due to an internal velocity distribution.

---

Résumé La genèse des »Schlingen« dans la partie méridionale des Alpes de l'Oetztal (Alpes orientales) a été jusqu'à présent rapportée principalement à des contraintes extérieures. Les structures plissées ont été dès lors expliquées dans cette région comme plis de ploiement et plis semblables. Si on considère la grande plasticité des roches lors du plissement, on doit admettre un autre mécanisme de plissement. Les auteurs essaient d'expliquer les structures plissées comme le résultat d'un processus d'écoulement qui dépendrait de la répartition des vitesses. Utilisant un programme établi parHarburgh &Bonham-Carter et présentant diverses conditions marginales, ils obtiennent par simulation des figures d'écoulement figurées comme vitesses vectorielles. Ces résultats sont des structures observées sur le terrain; ils sont confrontés aux figures produites lors des essais expérimentaux. La bonne concordance indique qu'on peut envisager les structures ptygmatiques comme résultant de la répartition interne des vitesses.

---

Ötz ( ) , , . , - . . . Harbburch' Bonham-Carter'o , , . . , , .

  相似文献