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1
Content available Application of genetic algorithms for the estimation of hydraulic conductivity
Bartlewska-Urban M., Strzelecki T.
Studia Geotechnica et Mechanica
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2018
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Vol. 40, nr 2
140--146
EN
In the study described here model calibration was performed employing the inverse analysis using genetic algorithms (GA). The objective of analysis is to determine value of the coefficient of hydraulic conductivity, k. The commonly used method for the determination of coefficient of hydraulic conductivity based on Terzaghi consolidation leads to an underestimation of the value of k as the Terzaghi model does not take into account the deformation of soil skeleton. Here, an alternative methodology based on genetic algorithms is presented for the determination of the basic parameters of Biot consolidation model. It has been demonstrated that genetic algorithms are a highly effective tool enabling automatic calibration based on simple rules. The values of the coefficient of hydraulic conductivity obtained with GA are of at least one order smaller than values obtained with the Terzaghi model.
2
Content available Numerical analysis of road pavement thermal deformability, based on Biot viscoelastic model of porous medium
Bartlewska-Urban M., Zombroń M.
Studia Geotechnica et Mechanica
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2016
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Vol. 38, nr 1
15--22
EN
The following study presents numerical calculations for establishing the impact of temperature changes on the process of distortion of biphase medium represented using Biot consolidation equations with Kelvin–Voigt rheological skeleton presented, on the example of thermo-consolidation of a pavement of expressway S17. We analyzed the behavior of the expressway under the action of its own weight, dynamic load caused by traffic and temperature gradient. This paper presents the application of the Biot consolidation model with the Kelvin–Voigt skeleton rheological characteristics and the influence of temperature on the deformation process is taken into account. A three-dimensional model of the medium was created describing the thermal consolidation of a porous medium. The 3D geometrical model of the area under investigation was based on data obtained from the land surveying and soil investigation of a 200 m long section of the expressway and its shoulders.
3
Content available Building a numerical model of the filtration flow in the “Żelazny Most” flotation tailings disposal lake
Strzelecki T., Maniecki Ł., Bartlewska-Urban M.
Studia Geotechnica et Mechanica
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2015
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Vol. 37, nr 1
93--104
EN
The paper presents results of numerical computations of the filtration flow of liquid contaminated wastes through the Żelazny Most flotation tailings disposal lake. Unlike the preceding papers [5]–[7], it takes the geological structure of the subsoil into account. A three-dimensional numerical model of the lake was created for computing purposes. Data on some of the effective model parameters were acquired from laboratory tests of the material taken from the lake site. The other data were taken from the literature for media of similar properties. The results of the computations carried out using the model can be a basis for future numerical analyses aimed at determining the consolidation of the flotation tailings disposal lake and its subsoil, and the stability of the lake.
4
Content available remote Determination of effective parameters of Biot model with the Kelvin–Voight rheological skeleton
Bartlewska-Urban M., Strzelecki T., Urban R.
Archives of Civil and Mechanical Engineering
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2015
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Vol. 15, no. 4
1173--1179
EN
This paper presents results of laboratory tests aiming in estimation of the effective parameters of the Biot model with the rheological skeleton for the samples collected at the flotation waste landfill “Żelazny Most”. In order to determine the effective parameters series of tests were performed in the laboratory of the Faculty of Civil Engineering at the National University of Ireland in Galway. Estimation of model parameters was performed with the use of optimization. It consists on searching the parameter space for the optimal set of values, in terms of the least square errors between the results of experiments and the results of calculations with the model. This paper presents the results of experiments on samples specially prepared for the experiment. More detailed picture of the results obtained is presented in a doctoral thesis “Determination of effective parameters of rheological models of cohesive soils” [1].
5
Content available Effect of variation of temperature field on the process of thermal consolidation of tailings pond “Żelazny Most”
Bartlewska-Urban M., Strzelecki T.
Studia Geotechnica et Mechanica
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2014
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Vol. 36, nr 2
57--65
EN
The following study presents numerical calculations for establishing an impact of temperature changes on the process of distortion of bi-phase medium. The Biot consolidation equations with Kelvin–Voigt rheological skeleton were used for that purpose. The process was exemplified by thermal consolidation of post floatation dump “Żelazny Most”. We analyzed the behavior of the landfill under the action of its own weight, forces of floating filtration and temperature gradient. Values of certain effective parameters of model were obtained during laboratory tests on material obtained from the landfill. The remaining data for mediums with similar characteristics were taken from literature. The results obtained from the stress state in the landfill allow the magnitude of plasticity potential to be specified based on known strength criteria. Change in the value sign of the plasticity potential clearly testifies to the emergence of an area of plasticity of material from landfill, however, this does not indicate the loss of stability of this hydrotechnical structure.
6
Content available Selected problems relating to the dynamics of block-type foundations for machines
Zombroń M., Mironowicz W., Bartlewska-Urban M., Smolińska J.
Mining Science
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2014
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Vol. 21
95--104
EN
Atypical but real practical problems relating to the dynamics of block-type foundations for machines are considered using the deterministic approach and assuming that the determined parameters are random variables. A foundation model in the form of an undeformable solid on which another undeformable solid modelling a machine is mounted via viscoelastic constraints was adopted. The dynamic load was defined by a harmonically varying signal and by a series of short duration signals. The vibration of the system was investigated for the case when stratified ground (groundwater) occurred within the side backfill was present. Calculation results illustrating the theoretical analyses are presented.
7
Content available Numerical calculation of deformation of three dimensional sample in triaxial apparatus under external load and temperature field
Bartlewska-Urban M., Strzelecki T.
Studia Geotechnica et Mechanica
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2013
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Vol. 35, nr 1
27--40
EN
This study presents the results of calculations of the of thermo consolidation process of porous medium with the rheological Kelvin–Voigt skeleton, obtained numerically with the use of Flex.PDE. It is a continuation of the discussion on the phenomenon of thermal consolidation. A 3D problem considered boils down to solving the problem of the porous column filled with a liquid and treated by applying uniaxial compression load through a porous plate, allowing free flow of liquid from the center. To the sample affected by external lateral pressure. Numerical solution assumes compressing the sample at properly defined boundary conditions. The aim of this study was to describe the influence of external load and temperature gradient in the deformation tests for the case when the lateral surface is a good conductor of heat, and where the lateral surface of the sample does not conduct heat. The results obtained, in the context of further research, can also be used to determine the influence of other parameters of the state and model parameters on the process of thermo poroelasticity of the Biot model with rheological skeleton.
8
Content available remote Thermal consolidation of porous medium with a rheological Kelvin–Voigt skeleton
Bartlewska-Urban M., Strzelecki T.
Studia Geotechnica et Mechanica
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2012
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Vol. 34, nr 3
17--35
EN
This study presents calculations results of thermal consolidation process of the porous medium with the rheological Kelvin–Voigt skeleton, obtained numerically with the use of Flex.PDE software. The investigated calculation scheme consisted of the porous column filled with a liquid. The vertical load was applied to the top surface of the column through a porous plate allowing the free flow of liquid through this surface. Numerical solution is based on compression of the sample at appropriately defined boundary conditions. The aim of this study was to describe the influence of external load and temperature gradient on the deformation tests progress at different values of three parameters: λ, rs and cv . The results obtained, in the context of further research, can also be used for the determination of the influence of other parameters of the state and model parameters on the process of thermo poroelasticity of Biot model with rheological skeleton.
9
Content available Numerical calculations of the consolidation of flotation waste landfill 'Żelazny Most' based on Biots model with the Kelvin-Voight rheological skeleton
Strzelecki T., Bartlewska-Urban M.
Archives of Civil Engineering
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2011
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Vol. 57, nr 2
199-213
EN
This paper presents simulation results of the consolidation process of the flotation waste landfill "Zelazny Most". The mathematical model used in presented research is based on Biot's model of consolidation and is extended with rheological skeleton. The load is the mass pressure of the landfill itself. The initial point selected for calculations was based on the ground water level calculated in a landfill. The creeping process in this waste landfill was analyzed along the north-south section. The solution is therefore 2D with the assumption of a plane strain state. Effective model parameters data were obtained in laboratory tests on the material from the waste landfill. Results obtained for a stress state in a storage state can help to determine whether the adopted linear model of visco-elastic medium does not lead to changes in the Coulomb-Mohr potential yield, showing the emergence of plasticity of material storage areas.
PL
W pracy przedstawiono wyniki symulacji procesu konsolidacji składowiska odpadów poflotacyjnych Żelazny Most w oparciu o model matematyczny konsolidacji Biota ze szkieletem reologicznym pod działaniem ciężaru własnego składowiska. Punktem wyjścia do obliczeń było obliczone zwierciadło wód podziemnych w składowisku. Zagadnienie pełzania składowiska wykonano w przekroju północ-południe przez składowisko. Rozwiązanie jest więc typu 2D przy założeniu płaskiego stanu odkształcenia. Dane dotyczące parametrów efektywnych modelu uzyskano w badaniach laboratoryjnych na materiale uzyskanym na składowisku. Uzyskane wyniki stanu naprężenia w składowisku pozwalają określić, czy przyjęty liniowy model ośrodka lepko sprężystego nie prowadzi do pojawienia się zmian znaku wartości potencjału plastyczności Coulomba-Mohra, co świadczyłoby o pojawianiu się obszarów uplastycznienia materiału składowiska.
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