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Wyszukujesz frazę "hydrotechnical constructions" wg kryterium: Temat


Wyświetlanie 1-4 z 4
Tytuł:
The analysis of factors influencing the dynamics of lowland riverbed erosion downstream of the Jeziorsko reservoir dam (central Poland)
Autorzy:
Smaga, A.
Wierzbicki, J.
Wierzbicki, M.
Hämmerling, M.
Radaszewski, R.
Powiązania:
https://bibliotekanauki.pl/articles/2060571.pdf
Data publikacji:
2017
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
river erosion
geotechnical parameters
hydrotechnical constructions
physical model
Opis:
Increased riverbed erosion could recently be observed in close vicinity of hydrotechnical constructions in many lowland rivers. The immediate effect of erosion in this case is a very significant reduction of the riverbed level over a considerable distance, downstream of large reservoir dams. This process is influenced simultaneously by both hydraulics of river flow and geotechnical properties of soil eroded. The paper presents an analysis of parametric changes in the level of river bottom and grain size of bed material, and the relative density in the context of changes in hydrological conditions and diversity of engineering-geological conditions. As the result, a multiparametric model of erosional potential of riverbed sediments has been proposed, which can significantly help in proper planning of locations and construction of correction thresholds under given hydraulic conditions of the river.
Źródło:
Geological Quarterly; 2017, 61, 4; 926--933
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A study on fibre-reinforced concrete elements properties based on the case of habitat modules in the underwater sills
Autorzy:
Kurpińska, Marzena
Grzyl, Beata
Kristowski, Adam
Powiązania:
https://bibliotekanauki.pl/articles/259547.pdf
Data publikacji:
2020
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
hydrotechnical constructions
fibre-concrete
mechanical concrete
strength
X-ray tomography
Opis:
Hydrotechnical constructions are mostly objects functioning in extreme conditions and requiring a custom-made construction project. In the case of using prefabricated elements, it is required to develop production, transport, assembly, conservation and repair technology. Concerning the problem of concrete cracks, modern repair systems allow positive effects to be achieved in many cases of concrete elements repair. In this work an attempt has been made to assess the properties of concrete, situated in the Baltic Sea environment, in which traditional rebar was partly replaced by dispersed fibre-phase. Fibre-reinforced concrete belongs to the group of composite materials. The presence of fibres helps to increase the tensile strength, flexural strength and resilience and also prevents the appearance of cracks. In the given paper we will also discuss basic parameters of steel and polymer fibres and the influence of both types of fibres on the maturing and hardened concrete. In this work special attention has been paid to the advantages of polypropylene and polymer fibres with regard to commonly-known steel fibres. The use of synthetic fibres will be advantageous in constructions where the reduction of shrinkage cracks and high resilience are essential. On top of that, the use of synthetic fibres is highly recommended when constructing objects that will be exposed to the impact of an aggressive environment. Undoubtedly, polymer fibres are resistant to the majority of corrosive environments. Fibre-reinforced concretes are a frequently implemented construction solution. The possibility of concrete modification allows the emergence of new construction materials with improved physical-mechanical properties, under the condition of being applied relevantly.
Źródło:
Polish Maritime Research; 2020, 1; 143-151
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wykorzystanie metod geoinformacyjnych w badaniach morfodynamiki koryta Wisły w Warszawie
The use of geoinformation methods in Vistula channel morphodynamic research in Warsaw
Autorzy:
Falkowski, T.
Ostrowski, P.
Powiązania:
https://bibliotekanauki.pl/articles/2075278.pdf
Data publikacji:
2015
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
procesy korytowe
aluwia korytowe
budowle hydrotechniczne
GIS
channel processes
alluvia substratum
hydrotechnical constructions
Opis:
Prerequisite for rational river valleys management is estimation of its evolution processes causes and directions. Such analysis requires from geologist great number of different information, acquisition of which is very often associated with difficulties resulting (for instance) from channel zone inaccessibility. Besides accuracy in location of the observation points such works require also ability in registration of environment changes during short observation periods (e.g. on the base of subsequent measurement campaigns results) as well as during long periods (e.g. comparison of the topographic or remote sensing archival data ). The perfect tool for such purposes, which is capable to integrating various research results are geographic information systems. In the regulated, downtown section of the Warsaw Vistula channel since the 60s of the last century to the early XXI century was recorded a steady decline in the level of the medium and low water flow. This process became a threat for the channel zone infrastructure. At the same time above and below this channel section, in the zone less equipped with the hydro-technical structures the process of aggradation was observed. This leads to increase of flood risk. The paper presents results of investigations, which were conducted in the Vistula River channel zone in Warsaw. During the research it was found that the reason for a particular channel environment behaviour in reaction on the management is the channel geology. In the narrow, regulated downtown channel section the contemporary alluvia substrate (built up with erosion resistant deposits) creates morphologically diverse protrusion. Upstream and downstream of that channel section the roof of alluvia substratum lowers. Lack of possibilities to deepening channel during the high waters passage in downtown narrowed channel reach affects the higher flow speeds and creates conditions of sediment transit . Shallow position of erosion resistant deposits floor affects also the thalweg course. Beyond the culmination of substratum Vistula represents the wild river, overloaded by alluvia.
Źródło:
Przegląd Geologiczny; 2015, 63, 3; 186--194
0033-2151
Pojawia się w:
Przegląd Geologiczny
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Florystyczne i fitocenotyczne wskaźniki stanu zachowania lasów zalewowych w miejskiej dolinie rzecznej
Flotistic and phytocenotic indicators of the conditions of riparian forests in the urban river valley
Autorzy:
Stefańska-Krzaczek, E.
Podgrudna, K.
Powiązania:
https://bibliotekanauki.pl/articles/989701.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
miasta
doliny rzeczne
lasy legowe
stan zachowania
flora
bogactwo gatunkowe
zbiorowiska lesne
zbiorowiska roslinne
zespol Ficario-Ulmetum minoris
Las Pilczycki
warunki siedliskowe
urban forests
disturbed forest
ficario−ulmetum minoris
hydrotechnical constructions
Opis:
Urban river valleys are exposed to strong anthropogenic pressure, but despite these distortions they provide important habitats in urban areas. Not embanked forests are particularly valuable in urban river valleys as they represent fragments of natural vegetation in a highly changed environment. The study assesses the flora and structure of forest communities in a riparian urban forest complex that is under the direct influence of river water. Las Pilczycki Forest in Wrocław (SW Poland) is such a riparian forest island. We analysed the species richness and composition in terms of the phytocoenoses variability and their syntaxonomic classification. We also investigated if the vegetation can indicate a spatial differentiation in habitat conditions. Floristic and phytosociological data were collected from 70 circular plots (100 m&suo2; each) located in a grid. A total of 81 species were recorded, with a mean of 21 species per plot. Most frequent were: Acer campestre, Acer platanoides, Anemone nemorosa, Ficaria verna, Fraxinus excelsior, Galium aparine, Geum urbanum, Impatiens parviflora and Sambucus nigra. In biological spectrum the most numerous were hemicryptophytes, megaphanerophytes and geophytes. The number of alien species was minor (9% of the flora). The most frequent anthropophyte was Impatiens parviflora. Soil moisture, acidity and fertility indices exhibited spatial correlations and they were higher in the western part of the forest. The moisture index was also higher in the northern part. Species richness ranged from 13 to 32 (with a mean of 21 species). Two forms of Ficario−Ulmetum minoris were identified: with Galanthus nivalis and with Tilia cordata. The first was a well−structured riparian community, while the latter one represented the drained floodplain forest. Vegetation units are spatially separated, in the western part of the forest prevails form with Galanthus nivalis, while in the east – with Tilia cordata. In isolated alluvial forests of urban area local site conditions are crucial for the vegetation patches, because of the distortion of river valleys. The absence of flood embankments is not a sufficient condition for maintaining proper structure of riparian forests.
Źródło:
Sylwan; 2015, 159, 01; 82-88
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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