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1
Content available Problematyka badań współczynnika filtracji w aparacie trójosiowego ściskania
Kaczmarek Łukasz, Dąbska Agnieszka, Popielski Paweł
Przegląd Geologiczny
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2022
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Vol. 70, nr 5
417--423
EN
Laboratory tests, which enable determination of the permeability properties of soil, are distinguished by the accuracy and relatively shorttesttime. Moreover, laboratory methods using a triaxial compression apparatus expand capability for tests with a different filtration regime and a spatial stress state applied on the analysed material. Such flexibility of research procedures allows for a number of scientific and engineering applications. The article outlines the construction of the triaxial apparatus system dedicated to filtration tests, their procedure, and important interpretation aspects.
2
Content available Krótki przegląd badań współczynnika filtracji gruntów
Popielski Paweł, Dąbska Agnieszka, Kaczmarek Łukasz
Przegląd Geologiczny
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2022
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Vol. 70, nr 5
410--416
EN
Many research methods enable the determination of the permeability properties of the soil. These methods differ, inter alia, in accuracy, complexity, application ranges, and technical conditions. The choice of a particular method is often dictated by the purpose of determining the hydraulic conductivity. The review of the most popular methods facilitates the optimization of the selection, as well as the application of mutually verifying methods or using them at different stages of the research. The article summarizes selected methods of determining the soil hydraulic conductivity from common research groups, including correlation, laboratory, and field methods, as well as less frequently used geophysical methods.
3
Content available Calculation model of pipeline resistance for cemented paste backfill considering thixotropy
Chang Yingjie, Zhang Youzhi, Gan Deqing, Wang Xinyi, Du Shuangcheng
Archives of Mining Sciences
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2022
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Vol. 67, no. 2
303--316
EN
The rheological behaviour of cemented paste backfill (CPB) has an important influence on the stability of its transportation in pipelines. In the present study, the time-dependent rheological behaviour of CPB was investigated to elucidate the effects of time and solid content. Experimental results showed that when CPB is subjected to a constant shear rate, the shear stress gradually decreases with time before finally stabilis ing. When the solid content was 60%~62%, a liquid network structure was the main factor that influenced the thixotropy of CPB, and the solid content had less influence. When the solid content was 64%~66%, a floc network structure was the main factor that influenced the thixotropy of CPB, and the solid content had a more significant influence on the thixotropy than the shear rate. The initial structural stability of CPB increased with the solid content, and this relationship can be described by a power function. Based on the experimental results, a calculation model of pipeline resistance considering thixotropy was proposed. The model was validated by using industrial experimental data. The current study can serve as a design reference for CPB pipeline transportation.
4
Content available Hydraulic gradient prediction for solid-water mixture flow through horizontal pipelines of different diameters and roughness and solids concentrations
Osra Faisal A.
Journal of Water and Land Development
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2021
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no. 49
267--272
EN
In wastewater treatment plants, large pumps are often used to accommodate unknown hydraulic properties of solid-water mixture flow. The use of large pumps translates into higher purchasing and operating costs. Wastewater mixture is pumped with solids of different types and concentrations through pipelines. The design of these ducts is mainly based on the hydraulic laws of solid-water mixture which is represented by a corrected friction coefficient corresponding to the concentration of solids in water. This paper experimentally studies hydraulic properties of solid-water mixtures in pipelines by the varying Froude number (Fr), which represents the velocity mixture, solid concentration, pipeline diameter and pipeline material type-roughness coefficient. The experiments have been conducted in the wastewater treatment plant where six solid concentrations can be found ranging from 2 to 12% by weight. The pipe diameter ranges between 100 to 300 mm. It has been found that both the friction coefficient and the hydraulic gradient ameliorate with the increase of the pipeline roughness and the solids concentration in the water mixture, whereas the Fr drop with the diameter of the pipeline. The results are translated into curves and equations to predict the corrected pipeline friction coefficient and the hydraulic gradient of the solid-water mixture flow through horizontal pipelines at various solids concentrations, roughness and diameters.
5
Content available Zmienność współczynnika filtracji w zależności od spadku hydraulicznego na przykładzie badań glin z miejscowości Różanka
Szczepański T., Wójcik E., Gawriuczenkow I.
Biuletyn Państwowego Instytutu Geologicznego
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2011
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nr 446 (2)
417--421
PL
Artykuł poświęcony jest problematyce wyznaczania w laboratorium współczynnika filtracji, jednego z istotnych kryteriów doboru gruntu jako materiału izolacyjnego. Program badań obejmował 3 serie pomiarów współczynnika filtracji na próbkach gliny lodowcowej kompleksu północnopolskiego, założono w nim różne warunki gradientu hydraulicznego i naprężenia. Wyniki świadczą o znacznej zmienności współczynnika filtracji w zależności od warunków badania, co sygnalizuje potrzebę doprecyzowania istniejących wytycznych badań przepuszczalności.
EN
The paper focuses on the problems of determining the permeability coefficient, one of the important criteria for selecting the ground as a sealing material. The research program included three series of measurements of the permeability coefficient on samples from North-Polish complex till, using different conditions of stress and hydraulic gradient. The results show a considerable variability of the coefficient depending on the studied conditions, which indicates the need for research to clarify the existing guidelines for permeability studies.
6
Content available remote Analiza zmian gradientu hydraulicznego w charakterystykach przepływu słabonośnego podłoża
Malinowska E., Szymański A.
Przegląd Naukowy Inżynieria i Kształtowanie Środowiska
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2009
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Vol. 18, No. 4
35--47
PL
W artykule przeanalizowano zmiany wartości gradientu hydraulicznego w zależności od wartości przyłożonego obciążenia zewnętrznego na słabonośne podłoże organiczne. Analizę zmian przedstawiono w funkcji prędkości przepływu wody oraz wskaźnika porowatości, którego wysoka początkowa wartość, jak wykazały badania w podłożu torfowym, znacząco maleje wraz we wzrostem naprężeń konsolidacyjnym. Analizę przeprowadzono na wynikach badań przepływu wody w słabonośnym ośrodku porowatym wykorzystując metodę flow-pump, tj. stałego, wymuszonego przepływu.
EN
In this review paper the changes of hydraulic gradient in the flow characteristics is presented. The analysis has been obtained in the value of loaded effective stress in soft soil. The relationship between fl ow velocity and hydraulic gradient is nonlinear. The results of soft soils used to the analysis were obtained in laboratory using the flow-pump technique. To describe the permeability characteristics the prelineary and postlineary phases should be considered. The prelineary phase characterises the flow at very low hydraulic gradient which usually appears in situ. The permeability characteristics show the strong changes of hydraulic gradient under different values of effective stress.
7
Content available remote Zmiana współczynnika filtracji układu piasek średni-geowłóknina K 500
Wojtasik D., Krzywosz Z.
Przegląd Naukowy Inżynieria i Kształtowanie Środowiska
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2005
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Vol. 14, No. 1
169--178
EN
The paper presents the results of laboratory tests carried out in the modified soil-geotextile permeametr (Fig. 1) recommended in ASTM standard D 5101-90. Laboratory tests were performed on nonwoven geotextile K-500 (Tab. 1) and medium sand (Tab. 2). In ftgures 2 and 3 the change in permeability coefficient in soil-geotextile system and soil under different hydraulic gradients are shown. The relationship for the evaluation of the change in coefficient in soil-geotextile system based on the initial values of the permeability coefficient of geotextile and soil as well as hydraulic gradient is proposed.
8
Content available remote Zmiana współczynnika filtracji w układzie grunt-geowłóknina
Lechowicz Z., Krzywosz Z., Wojtasik D.
Przegląd Naukowy Inżynieria i Kształtowanie Środowiska
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2003
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Vol. 12, No. 2
38--47
EN
The paper presents the results of laboratory tests carried out in the modified soil-geotextile permeameter (Fig. 1) recommended in AST Mstandard D 5101-90. Laboratory tests were performed on nonwoven geotextile K-500 (Tab. 1) and clayey sand (Tab. 2). In Figures 2 and 3 the change in permeability coefficient in soil-geotextile system and soil under different hydraulic gradients are shown. The relationship for the evaluation of the change in permeability coefficient in soil-geotextile system based on the initial values of the permeability coefficient of geotextile and soil as well as hydraulic gradient is proposed.
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