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Zależności między efektywnymi parametrami wytrzymałościowymi ϕ' i c' a parametrami fizycznymi gruntów spoistych z terenów Polski, cz. 1

Sahajda Krzysztof, Lofitckii Artem

Inżynieria i Budownictwo

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2023

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R. 79, nr 5-6

309--318

PL

W pracy przedstawiono podsumowanie wyników pomiarów efektywnych parametrów wytrzymałościowych ϕ' i c' gruntów spoistych z terenu Polski. Sprawdzono, czy możliwe jest wykazanie korelacji między tymi parametrami a parametrami fizycznymi stosowanymi jako miara spoistości gruntu, tj. wskaźnik plastyczności Ip i granica płynności WL. Dodatkowo sprawdzono, czy występuje monotoniczna zależność między efektywnymi parametrami wytrzymałościowymi ϕ' i c' a stopniem plastycznosci IL.

EN

In the paper results of effective shear-strength ϕ' and c' parameters measurement was summarized for cohesive soils from the entire Poland. It was verified if the well established correlations between these parameters and plasticity properties i.e. plasticity index Pl, and liquid limit WL are valid for the database. Moreover, it was tested if a monotonic relationship between effective shear strength parameters and ϕ' and c' and liquidity index LI, does exist.

2

Thermally treated clay as a stabilizing agent for expansive clayey soil: some engineering properties

Al-Swaidani A. M., Hamood I., Meziab A.

Studia Geotechnica et Mechanica

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2018

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Vol. 40, nr 3

220--232

EN

The objective of this research was to investigate the effect of adding thermally treated clay on some engineering properties of the untreated expansive clayey soil. Three expansive clayey soil samples obtained from three different sites in the south of Syria have been investigated. They were thermally treated up to three different levels (450°C, 650°C and 850°C) for 3 hours. Three replacement levels of thermally treated clay were used, i.e. 0%, 10% and 20%. The X-ray diffractometer (XRD) technique has been used to detect the crystalline and glassy phase in the clayey samples before and after the thermal treatment. Pozzolanic activity of the thermally treated clayey soil has been studied using the modified Chapelle test and the mechanical strength test at each of the temperature levels. Atterberg limits, compaction, free swell, swelling pressure and linear shrinkage have particularly been investigated. Test results revealed the positive effect of thermally treated clay when added to the natural soil. Plasticity index (PI) was reduced by about 60% when 20% thermally treated clay was added to the natural soil. In addition, 6% lime was added to further investigate the combined effect of lime and calcined clay on the properties of the clayey expansive soil. All investigated properties were significantly improved when 20% thermally treated soil and 6% lime were added together. For instance, swelling pressure and linear shrinkage values were reduced to less than 15% or even much less when compared with those of the natural soil. Scanning electron microscopy (SEM) and energydispersive X-ray (EDX) analysis were employed as well.

3

The value of plasticity index (Ip) and liquidity index (IL) of North Polish ablation boulder clays and varved clays depending of the method of its determination

Krawczyk D., Flieger-Szymańska M.

Przegląd Naukowy Inżynieria i Kształtowanie Środowiska

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2018

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Vol. 27, No. 2

167--174

EN

Article determins a correlation between the values of the plasticity and liquidity index (Ip, IL) of cohesive soils achieved by various laboratory methods (on the basis of Casagrande apparatus and cone penetrometer method) and consists research results on natural clayey soils of known origin and strictly defined genetic features, described in detail in terms of particle size and mineralogy (the North Polish ablation boulder clays and varved clays).

4

Wyznaczanie granicy płynności metodą Casagrandego i penetrometrem stożkowym

Matusiewicz W., Lechowicz Z., Wrzesiński G.

Przegląd Naukowy Inżynieria i Kształtowanie Środowiska

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2016

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Vol. 25, No. 3

290--300

PL

W artykule przedstawiono wyniki badań laboratoryjnych granicy płynności (wL) gruntów spoistych wyznaczonej przy pomocy aparatu Casagrandego i penetrometru stożkowego dla stożków o kątach wierzchołkowych 60° i 30°. Badania przeprowadzono dla czterech podstawowych grup gruntów spoistych sklasyfikowanych ze względu na spoistość w odniesieniu do procentowej zawartości frakcji iłowej. Przeprowadzone badania wskazują, że dla gruntów spoistych o granicy płynności mniejszej od 50% różnice między granicą płynności wyznaczoną według metody Casagrandego a granicą płynności określoną stożkiem o kącie wierzchołkowym 60° są niewielkie (±3%). Dla gruntów spoistych o granicy płynności gruntu większej od 50% granica płynności wyznaczona metodą Casagrandego jest o 3–13% większa niż granica płynności określona stożkiem o kącie wierzchołkowym 60°, przy czym mniejszą różnicę uzyskano dla stożka o kącie 30°. W gruntach spoistych o zawartości frakcji iłowej mniejszej niż 5%, na przykład piaski gliniaste (clSa), ze względu na trudności w wykonaniu rowka, łatwiej wyznacza się granicę płynności przy pomocy penetrometru stożkowego niż metodą Casagrandego.

EN

The paper presents the laboratory test results of liquid limit (wL) of cohesive soils determined by Casagrande method and cone penetrometer with apex angles of 60° and 30°. The study was performed on the four groups of cohesive soils classified due to the clay fraction content. Test results indicates that in cohesive soils with the liquid limit less than 50% the differences between liquid limit determined by the Casagrande method and cone penetrometer with angle of 60° are small (±3%). In cohesive soils, with liquid limit more than 50%, liquid limit determined by Casagrande method in comparison with liquid limit obtained from cone penetrometer with angle of 60° is higher about 3–13%, however a smaller difference was obtained using cone penetrometer with angle of 30°. In cohesive soils containing clay fraction of less than 5%, e.g. clayey sand (clSa), due to difficulty in the formation of groove, it is better to determine the liquid limit by cone penetrometer than by Casagrande method.

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Morphological, anatomical and physiological leaf trait plasticity of Sesleria nitida (Poaceae) in open vs shaded conditions

Puglielli G., Crescente M. F., Frattaroli A. R., Gratani L.

Polish Journal of Ecology

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2015

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Vol. 63, nr 1

10--22

EN

An expression of plants response to light availability is their shade tolerance which refers to the capacity of a given plant to tolerate low light levels. Survival in a shaded environment can determine phenotypic consequences at morphological and/or physiological levels and such changes may be crucial to survive in heterogeneous and variable conditions. However, the potential plastic response of a given plant trait may be large but the observed plasticity may be lowered by resource limitations or environmental stress factors. In this context, the aim of this research was to analyze morphological, anatomical and physiological leaf traits variations of Sesleria nitida Ten. growing in different light conditions. In particular, plants growing in open (PO) and shade (PU) conditions were analyzed. The results show a 35% higher specific leaf area (SLA) in PU than in PO due to a 94% larger leaf area (LA). The higher height and width of the central and the major lateral vascular bundle in PO than in PU contribute to a higher net photosynthesis (PN) in sun than in shade conditions. Moreover, the 33% higher ratio between respiration (RD) and PN (RD/PN) in PU than in PO highlights the greater proportion of the carbon consumed by RD in the shade population requiring a greater metabolic effort for growth and maintenance. S. nitida in the shaded environment might be favored by the soil pH being a neutro-basophilous species and the larger soil water content (SWC) and mineral content contributing to maintain a positive carbon balance in this limiting condition. The plasticity analysis for open vs. the understory plants (mean plasticity index = 0.32) highlights the leaf trait variations useful to maintain a positive carbon balance where light availability is the main limiting factor. Knowledge of the capacity of S. nitida to first colonize and then modify its phenotype in response to the shade condition can contribute to a better understanding of its ecology.