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Wyszukujesz frazę "neogene clays" wg kryterium: Temat


Wyświetlanie 1-6 z 6
Tytuł:
Overconsolidation and microstructures in Neogene clays from the Warsaw area
Autorzy:
Kaczyński, R.
Powiązania:
https://bibliotekanauki.pl/articles/2059628.pdf
Data publikacji:
2003
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
neogene clays
microstructural parameters
porous space
OCR
Opis:
The main objective of the study was determine the loading history and establish the current state of consolidation of Neogene clays, to study their lithological and microstructural properties, and to define their geological-engineering properties. To accomplish this task, series of laboratory and field tests were performed. The tests were made on clays taken from pits excavated for underground stations and tunnels (A-14-A-15) in Warsaw and from 2 borehole cores taken from the Stegny experimental field. The tests showed that: the clays are historically overconsolidated with an OCR ratio of 25-50 and their current state of preconsolidation is OCR = 2-14; their range of clay microstructures, observed for the first time, are matrix-turbulent and turbulent-laminar and there was a clear anisotropy of quantitative parameters of the pore paces, these parameters varying with depth. The engineering-geological characteristics (physical and mechanical properties) of the clays were assessed. The results of the study can be used directly to evaluate the Neogene clays of the Warsaw area for their suitability as a subsoil for engineering projects and indirectly to accomplish the same with other overconsolidated soils, particularly in regard to the study methodologies applied and described.
Źródło:
Geological Quarterly; 2003, 47, 1; 43-54
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Expansivity of Neogene clays and glacial tills from Central Poland
Autorzy:
Izdebska-Mucha, D.
Wójcik, E.
Powiązania:
https://bibliotekanauki.pl/articles/2059738.pdf
Data publikacji:
2014
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
expansive soil
neogene clays
glacial tills
index parameters
Opis:
The revision of classification methodologies for determination of soil expansivity revealed that parameters most frequently used for this purpose are: the liquid limit, plasticity index and swelling parameters which also predominate in older systems of expansive soil assessment, regarded as classical. Seventy-nine soil samples, including Neogene clays and glaciall tills from Central Poland, with a wide range of plasticity were examined for a comparative analysis of soil expansivity with a use of eight empirical methods. The study revealed that Neogene clays are mostly highly and very highly expansive, while glacial tills exhibit low to medium expansivity. Compared to classifications considering soil mineralogy indicators, those correlated solely to Atterberg limits and related parameters were found to overestimate soil expansivity. It is evident that the classifications are in better agreement for glacial tills than for clays. The comparison of mineral composition measured and predicted from swelling tests yielded consistent results.
Źródło:
Geological Quarterly; 2014, 58, 2; 281--290
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of swell index and swelling pressure from suction tests : a case study of Neogene clays from Warsaw (Poland)
Autorzy:
Wójcik, E.
Gawriuczenkow, I.
Powiązania:
https://bibliotekanauki.pl/articles/2060572.pdf
Data publikacji:
2017
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
expansive soils
swell index
swelling pressure
soil suction
neogene clays
Opis:
The paper presents the results of swell index, swelling pressure and soil suction tests carried out on Neogene clays from Warsaw, depending on the water content, clay fraction, liquid limit, plasticity index, cation exchange capacity, and content of clay minerals and beidellite. These clays are considered expansive soils in Poland, as they are vulnerable to water content variations in the active zone, which result in their volume change and, in consequence, cause damage of foundations and other construction elements. A number of physical, chemical and mineral properties were determined for these clays. The swelling tests were carried out on samples precompacted in Proctor apparatus, at various initial values of water content. The analyses have shown exponential relation of swell index, swelling pressure and suction versus water content. In addition, the investigated relationship between the suction and swell characteristics of tested clays shows good correlation as a power function between these parameters. In addition, validity of correlations between fitting parameters of obtained relationships and soil index properties, such as clay fraction, liquid limit, plasticity index, cation exchange capacity, and content of clay minerals and beidellite, have been demonstrated. The empirical relations are characterized by high values of the correlation coefficient. A very high fit has also been found for a proposed relationship between the swell index and swelling pressure for tested clays.
Źródło:
Geological Quarterly; 2017, 61, 4; 738--750
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of expansivity of Neogene clays and glacial tills from central Poland on the basis of suction tests
Autorzy:
Izdebska-Mucha, D.
Wójcik, E.
Powiązania:
https://bibliotekanauki.pl/articles/2059660.pdf
Data publikacji:
2015
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
expansive soil
neogene clays
glacial tills
suction
suction compression index
heave
Opis:
This paper presents the characteristics of the expansivity and quantitative prediction of heave of clay soils from Poland based on suction testing. 11 Neogene clays and 6 glacial tills, differing in genesis and plasticity, were analyzed to identify the expansive potential using eight empirical methods. The laboratory studies included measurements of soil-water characteristic curves and soil index properties. Data from water content, volume and suction measurements served to determine the suction compression index Ch and the suction-water content index Dh/Dw of the soils examined. The values of these indices are clearly dependent of the clay fraction content in tested soils. Compared with glacial tills, Neogene clays are expected to exhibit larger changes in volume due to changes in soil suction. Comparative results of the evaluation of expansivity suggest that the chosen classification methodologies provided consistent expansion ratings for glacial tills, while values for Neogene clays vary from low to very high. The lowest expansivity classes have been obtained from evaluation based on soil suction. The McKeen (1992) method has been adopted for calculations of the potential field heave of Neogene clays and glacial tills. In order to provide a rational estimation of expansive soil behavior, specialists should take into consideration the specific site and design features.
Źródło:
Geological Quarterly; 2015, 59, 3; 593--602
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Identyfikacja składu mineralnego i pęcznienia gruntów spoistych na podstawie współczynnika swobodnego pęcznienia
Identification of clay soil mineralogy and swelling by the free swell ratio method
Autorzy:
Izdebska-Mucha, D.
Wójcik, E.
Powiązania:
https://bibliotekanauki.pl/articles/2085917.pdf
Data publikacji:
2016
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
iły neogeńskie
skład mineralny
kaolinit
montmorillonit
ekspansywność
współczynnik swobodnego pęcznienia
neogene clays
mineral composition
kaolinite
montmorillonite
expansivity
free swell ratio
Opis:
W artykule przedstawiono wyniki badań parametrów pęcznienia iłów neogeńskich serii poznańskiej z rejonu Mazowsza oraz iłów modelowych przygotowanych z bentonitu z Wyoming i kaolinitu z Sedlec. Określono parametry pęcznienia takie jak: zmodyfikowany wskaźnik swobodnego pęcznienia (MFSI) i współczynnik swobodnego pęcznienia (FSR) oraz przeprowadzono analizę ich zależności od chemizmu roztworu, składu mineralnego i zawartości frakcji iłowej. Ocena składu mineralnego gruntów naturalnych na podstawie współczynnika swobodnego pęcznienia FSR, zdefiniowanego jako stosunek objętości 10 g gruntu wysuszonego w 105°C po sedymentacji w roztworze 0,0025% NaCl do objętości osadu w nafcie, okazała się orientacyjna.
The paper presents the results of free swell measurements of Neogene clays and model clay mixtures composed of Wyoming bentonite and Sedlec kaolinite. Modified free swell index (MFSI) as well as free swell ratio (FSR) were determined and analyzed with respect to pore fluid chemistry, mineral composition and clay content. The FSR, defined as the ratio of the equilibrium sediment volume of 10-g oven dried soil in 0.0025% NaCl solution to that in kerosene, has proved to provide only a rough prediction of clay mineralogy in natural soils.
Źródło:
Biuletyn Państwowego Instytutu Geologicznego; 2016, 466; 77-85
0867-6143
Pojawia się w:
Biuletyn Państwowego Instytutu Geologicznego
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evidence of soils and paleosols in the Poznań Formation (Neogene, Polish Lowland)
Autorzy:
Duczmal-Czernikiewicz, A. M.
Powiązania:
https://bibliotekanauki.pl/articles/2059716.pdf
Data publikacji:
2013
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Poznań clays
Neogene
Polish Lowland
pedostructures
Opis:
A succession of stacked paleosol profiles was recognized in open pits in the western Wielkopolska region (Poland). Field observations and micromorphological studies made it possible to distinguish the following pedostructures, formed in contrasting environments: soil horizons, crystallaria, concretions, redoximorphic structures, Fe-Mn globulae and slickensides. In both soils (Holocene) and paleosols (Pleistocene or/and Pliocene?), surface horizons are present (horizon A), marked by rhizocretions. There are two separate carbonate soils. One of them contains calcite concretions and gypsum pedofeatures, presumably formed in arid or semi-arid conditions. Two of the soil profiles are probably truncated, and only subsurface horizons are present (horizon B). In some cases, paleosols are separated by sediment layers slightly influenced by pedogenesis (horizon BC). Carbonate soils (Bk) indicate water deficit during their formation. The presence of horizons with slickensides (Bss) indicates intervals with contrasting seasonal climates (wet and dry cycles). The profiles were influenced by gleying processes which caused redistribution of iron oxides and formation of iron and iron-manganese concretions. The pedostructures recognised reflect different climatic conditions as well as humidity changes during the time of their formation.
Źródło:
Geological Quarterly; 2013, 57, 2; 189--204
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-6 z 6

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