scholarly journals Comparison of Different Empirical Correlations to Estimate Permeability Coefficient of Quaternary Danube Soils

2018 ◽  
Author(s):  
Miklós Pap ◽  
András Mahler
Keyword(s):  
Grain Size ◽  
Permeability Coefficient ◽  
Carpathian Basin ◽  
Laboratory Measurement ◽  
Granular Soils ◽  
Empirical Correlations ◽  
Soil Parameter ◽  
Measurement Results

Permeability coefficient is the most significant soil parameter in seepage calculations. It has been recognized that permeability of granular soils is strongly related to the grain size, thus numerous empirical correlations have been developed to estimate permeability using its grain size characteristics. In this study the empirical correlations proposed by Hazen (1911), Carrier (2003) and Chapuis (2004) are evaluated and compared to laboratory measurement results. Quaternary Danube soils are very typical in the Carpathian basin, thus their permeability is an important question in many geotechnical applications.

scholarly journals Modeling of German Low Voltage Cables with Ground Return Path

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1265 ◽  
Author(s):  
Johanna Geis-Schroer ◽  
Sebastian Hubschneider ◽  
Lukas Held ◽  
Frederik Gielnik ◽  
Michael Armbruster ◽  
...  
Keyword(s):  
Low Voltage ◽  
Measurement Data ◽  
Analytical Calculation ◽  
Laboratory Measurement ◽  
Model Parameters ◽  
Calculation Methods ◽  
Modeling Approach ◽  
Measurement Results ◽  
Simulation Results ◽  
Return Path

In this contribution, measurement data of phase, neutral, and ground currents from real low voltage (LV) feeders in Germany is presented and analyzed. The data obtained is used to review and evaluate common modeling approaches for LV systems. An alternative modeling approach for detailed cable and ground modeling, which allows for the consideration of typical German LV earthing conditions and asymmetrical cable design, is proposed. Further, analytical calculation methods for model parameters are described and compared to laboratory measurement results of real LV cables. The models are then evaluated in terms of parameter sensitivity and parameter relevance, focusing on the influence of conventionally performed simplifications, such as neglecting house junction cables, shunt admittances, or temperature dependencies. By comparing measurement data from a real LV feeder to simulation results, the proposed modeling approach is validated.

Similarity of internal stability criteria for granular soils

1992 ◽  
Vol 29 (4) ◽  
pp. 711-713 ◽  
Author(s):  
Robert P. Chapuis
Keyword(s):  
Grain Size ◽  
Groundwater Flow ◽  
Distribution Curve ◽  
Fine Particles ◽  
Frost Damage ◽  
Granular Soils ◽  
Internal Stability ◽  
Stability Criteria ◽  
Mathematical Expressions ◽  
Internal Instability

Internal instability produces segregation in fine particles, modifies drainage properties, and increases pore pressures, capillary retention, and possible frost damage. Three criteria are commonly used to assess the internal instability of granular soils. It is shown here that they can take similar mathematical expressions where the secant slope of the grain-size distribution curve indicates the risk of internal instability. Key words : suffossion, groundwater flow, gradation.

Effect of grain size distribution on the maximum and minimum void ratios of granular soils

2020 ◽  
Vol 17 (2) ◽  
pp. 26-33
Author(s):  
Jose Duque ◽  
William Mario Fuentes Lacouture ◽  
Jorge Andres Barros Ayala
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Granular Soil ◽  
Granular Soils ◽  
Size Distributions ◽  
Experimental Procedure ◽  
Practical Applications ◽  
Grain Size Distributions ◽  
Properties Of Soil

The maximum and minimum void ratios define the loosest and densest conditions of a granular soil. Correlations with some granulometric properties of soil are of interest for practical applications, but the experimental procedure to determine these variables can be time consuming. In this work the influence of the grain size distribution on the maximum and minimum void ratios is investigated. Twenty different granular soils with varying grain size distributions were prepared and tested. The experimental results, together with a compilation of 56 additional results reported in the literature, are statistically analysed. The analysis is conducted to examine the influence of some granulometric properties (D10, D30 and D60) on the maximum and minimum void ratios. As a result, some correlations considering the aforementioned variables are proposed. Subsequently, it is shown that the proposed correlations have better agreement with the experimental data than other proposals reported in the literature. The paper ends with some concluding remarks.

Grain-Size Distribution of Granular Soils by Computer Vision

1997 ◽  
Vol 20 (4) ◽  
pp. 433 ◽  
Author(s):  
RC Chaney ◽  
KR Demars ◽  
SA Raschke ◽  
RD Hryciw
Keyword(s):  
Computer Vision ◽  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Granular Soils

Effect of Spatial Uncertainty of Unsaturated Zone Permeability Coefficient on Cl- Migration

2013 ◽  
Vol 838-841 ◽  
pp. 995-1002
Author(s):  
Yue Ying Wang ◽  
Xiang Li ◽  
Bei Dou Xi ◽  
Shun Guo Bai ◽  
Ming Xiao Li ◽  
...  
Keyword(s):  
Unsaturated Zone ◽  
Permeability Coefficient ◽  
Bayesian Method ◽  
Spatial Uncertainty ◽  
Contaminant Migration ◽  
Soil Parameter ◽  
Permeability Coefficients ◽  
Contamination Concentration ◽  
Hydrus 1D ◽  
Typical Soil

In order to study the effect of spatial uncertainty of soil parameter in unsaturated zone on contaminant migration, Permeability coefficient was chosen as a typical soil parameter to be researched. Bayesian method was used to deal with permeability coefficients and Monte-Carlo method was used to simulate spatial uncertainty of permeability coefficients. Numerical model of HYDRUS-1D was used to simulate the contaminant migration in the unsaturated zone taking spatial uncertainty of permeability coefficient into account. And Cl-was chosen as the contamination. The result was that: The distribution of contamination concentration presented a significant uncertainty, and compared with the case of ignoring spatial uncertainty of permeability coefficients in unsaturated zone, it is closer to the actual situation. Meanwhile, a suggestion about the value of initial concentration in numerical simulation of groundwater is given combining the results.

scholarly journals On the Relation between the Gas-Permeability and the Pore Characteristics of Furan Sand

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3803
Author(s):  
Dinesh Sundaram ◽  
József Tamás Svidró ◽  
Judit Svidró ◽  
Attila Diószegi
Keyword(s):  
Grain Size ◽  
Gas Permeability ◽  
Silica Sand ◽  
Size Distributions ◽  
Pore Characteristics ◽  
Measurement Results ◽  
The World ◽  
Grain Size Distributions ◽  
Molding Materials ◽  
Standard Gas

Furan sand is one of the most commonly used chemically bonded molding materials in foundries across the world. It consists of a furfuryl alcohol-based resin and an acid-based liquid catalyst. When the molding material comes in contact with the molten metal, it undergoes a thermal shock accompanied by a certain release of volatile gases. In order to evacuate these gases, molds and cores should have optimal gas permeability values and proper venting by design. If the volatile compounds are not appropriately evacuated, they are prone to enter the melt before the first layer of solidified metal is formed which can lead to the formation of gas-related casting defects. Standard gas permeability measurements are commercially available tools used in the industry to compare and to quality control different sands, however, they only provide reference numbers without actual units. Permeability in a standard unit, m2, provides uniformity and helps the comparison of results from difference sources. In this paper, a new method using Darcy’s law (prevalent in earth sciences), was adapted to measure the gas-permeability of furan samples made of silica sand with various grain size distributions. The effect of grain size distribution on the gas-permeability of furan sand samples was studied. Gas-permeability values in m2 were then correlated with mercury-porosity measurement results to bring new light on the relation between pore size, pore volume and the permeability of molding materials.

scholarly journals Investigation of sand in piping

2012 ◽  
pp. 115-128
Author(s):  
Laslo Nadj
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Solid Particles ◽  
Granular Soils ◽  
Volcanic Cone ◽  
Size Fractions ◽  
Grain Sizes ◽  
High Flood ◽  
Grain Size Fractions

For the investigation of the grain size distribution of the material washed out from the piping, we used 20 samples originating from different places on the Danube and the Tisza rivers. The grading characteristics of these samples were investigated based on selected grain sizes and the uniformity of gradients. Based on the investigations it has become possible to identify which grain size fractions are likely to be washed out, and how to characterize those fractions. Based on the grain size distribution curves it has been made possible to define the boundaries of the zone susceptible to piping. The zone limits of granular soils liquefied by earthquakes and the zone limits of the soil out washed from piping are very similar. This apparent correspondence already formerly raised the hypothetic question of whether piping occurring during high flood can be simulated by shape to similar surface liquefaction phenomena experienced during earthquakes, as in both cases a volcanic cone is formed through the crater of which water is constantly issuing, dragging away solid particles.

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