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The evolution of a Weichselian proglacial lake in NW Poland as revealed by static penetration tests

Wierzbicki Jędrzej, Paluszkiewicz Renata, Paluszkiewicz Ryszard

Geologos

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2011

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Vol. 17, No. 2

111--119

EN

The lithology, structure and geophysical characteristics of the glaciolacustrine clays deposited in the Wierzchowo proglacial lake were determined using static penetration tests (CPTU) in combination with standard lithological measurements. The deposits are divided into four lithological units (R1 to R4) on the basis of overconsolidation. Units R3 and R4 are separated by mass-flow deposits. The depositional conditions history of the lake result represent four phases: (1) an initial (low-energy) phase with the deposition of the rhythmically laminated sediments of units R1 and R2, which are divided by an erosional interval; (2) a phase of non-deposition with some desiccation structures and extended consolidation of sediments; (3) the main phase characterised by deposition of the rhythmically laminated sediments of unit R3; and finally, (4) the youngest phase, which represents alternations of deposition and erosion. The results show that sedimentation in the Wierzchowo proglacial lake was less continuous, and that the depositional processes were more complex than in the neighboring Złocieniec glacial lake.

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The influence of overconsolidation ratio on the "Gs - ε 1" dependence for cyclic loading of cohesive soils in the range of small strains

Jastrzębska M.

Studia Geotechnica et Mechanica

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2010

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Vol. 32, nr 1

23-34

EN

The subject of the paper comprises testing of a cohesive soil response to cyclic loading applied in the range of small strains (10(-5)÷10(-3)). To this end, tests of undrained cyclic shear in a triaxial apparatus were carried out on homogeneous material - kaoline from Tułowice. The tests were carried out on a modernised test bed, enabling full saturation of specimens using the back pressure method as well as a precise, local measurement of small strains by means of contactless microdisplacement sensors. While maintaining a constant deformation rate, during 10 cycles of unloading and reloading, the influence of overconsolidation ratio (OCR) at various levels of the deviator stress amplitude (A1 = 0.75∇q and A2 = 0.375∇q ) on the "Gs - ε 1" stiffness characteristics was investigated. When analysing the results obtained it has been found that the overconsolidated soils feature higher Gs values as compared with normally consolidated soils, where the differences are more significant for higher deviator stress amplitudes. In addition, the deviator stress amplitude increase results in a decline in the shear modulus Gs. At the same time soil strengthening in consecutive cycles is observed.

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Wzmacnianie gruntów słabych a problematyka zrównoważonego rozwoju budownictwa

Sękowski J.

Materiały Budowlane

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2009

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nr 2

31-33

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Wielkość prekonsolidacji iłów formacji poznańskiej charakteryzowana wartością stopnia YSR

Stróżyk J.

Zeszyty Naukowe. Inżynieria Środowiska / Uniwersytet Zielonogórski

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2007

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nr 134 (14)

159-166

PL

W pracy przedstawiono wyniki badań prekonsolidacji części stropowej mioplioceńskich iłów formacji poznańskiej. Wielkość prekonsolidacji określano poprzez wartość stopnia naprężenia uplastyczniającego YSR oraz naprężenia uplastyczniającego [...]. Stwierdzono, że wartość naprężenia [...] przyjmuje wartości od 80 do 1100 kPa i rośnie wraz z głębokością zalegania gruntu, natomiast wyznaczona wartość stopnia YSR wykazuje duże zróżnicowanie od 1,6 do 10,8 i nie wykazuje związku z głębokością zalegania gruntu.

EN

In paper the results of examinations the preconsolidation of the Poznań formation clays were presented. The preconsolidation was being determined through the value of Yield Stress Ratio YSR and yield stress [...]. Yield stress is one of the main parameter of the state of cohesive soils. The yield stress value for Poznań clays was from 80 for 1100 kPa and was growing along with depth, however the determined value of the YSR was showing big diversity from 1.6 for 10.8.