scholarly journals The Historical Earthworks of the Warsaw Citadel

2020 ◽  
Vol 12 (18) ◽  
pp. 7695
Author(s):  
Marek Wyjadłowski ◽  
Janusz Kozubal ◽  
Wojciech Damsz
Keyword(s):  
Rheological Model ◽  
Industrial Revolution ◽  
National Standard ◽  
Model Parameters ◽  
Destructive Testing ◽  
Ground Anchors ◽  
Standard Procedures ◽  
Load Tests ◽  
Geotechnical Tests ◽  
Military Engineering

In this study, we analyzed the methods and technologies used for constructing earthworks and military engineering in the latter period before the industrial revolution in Poland. The research object, the Warsaw Citadel, is a source of knowledge about military heritage from the aspect of conservation and protection of specific engineering achievements, which were dictated by early Russian geopolitical doctrine. Within the framework of the ongoing project of material heritage protection and popularization of history, the fortress has been transformed into a modern museum building. The new symbolic message of architecture was redefined, leaving behind the gloomy dominance elements in the scenery of the nearby city. In this study, reception tests of ground anchors were used for analysis. They were treated as a tool to determine the heterogeneity of fortification of historical earthworks. In the presented calculation procedure, limitations in the availability of geotechnical tests were overcome. Geological terrain layout and embankment excavation technology significantly impacted their quality and reliability. Currently, the embankments are slashed with anchored retaining walls. Ground anchors were used at short distances and were tested according to the national standard procedures. The results of the load tests are based on the physical properties of the subsoil, the conditions of contact with the supporting elements of the anchors, and the material properties. The soil interaction with the anchors is described using a rheological model, the constants of which were obtained using a fractional derivative model. The spatial variability of the rheological model parameters is presented using theoretical semivariograms matching the empirical data. The semivariograms explain the spatial correlation of the tested constants of the rheological model of the substrate with the anchors. The results of non-destructive testing were influenced by factors such as time and consolidation processes. The obtained results allowed us to directly draw conclusions about the repetitiveness of embankment features and indirectly about the quality of their construction.

scholarly journals Evaluation of Anthropogenic Substrate Variability Based on Non-Destructive Testing of Ground Anchors

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5131
Author(s):  
Marek Wyjadłowski ◽  
Janusz V. Kozubal ◽  
Zofia Zięba ◽  
Dmitri Steshenko ◽  
Dariusz Krupowies
Keyword(s):  
Rheological Model ◽  
Destructive Testing ◽  
Anthropogenic Origin ◽  
Nonlinear Fitting ◽  
Geostatistical Methods ◽  
Valley Slope ◽  
Ground Anchors ◽  
Slope Excavation ◽  
Load Tests ◽  
Ground Anchor

The purpose of this paper is to describe the variability of soil rheological properties based on research carried out using load tests of ground anchors under complex geotechnical conditions. The heterogeneity of soil should always be considered when designing geotechnical constructions. In the present case, the earthwork created at the Warsaw Slope revealed an embankment of anthropogenic origin, located in a geologically and geomorphologically complex area of the Vistula valley slope. Excavation protection was anchored mainly in soils of anthropogenic origin. When the acceptance tests of the ground anchor were completed, the subsoil randomness was confirmed using nondirect, geostatistical methods. A standard solid rheological model with nonlinear fitting to the data was used. This model was established to describe the creeping activity of the ground anchor more accurately. The characteristics of man-made embankments were described using the parameters obtained with the rheological model of the subsoil.

scholarly journals Biopolymer Drill-in Fluid Performance for Different Rheological Models using Statistical Characterisation

2019 ◽  
Vol 19 (1) ◽  
pp. 86-92
Author(s):  
M. Owusu ◽  
H. Osei
Keyword(s):  
Rheological Model ◽  
Rheological Behaviour ◽  
Primary Objective ◽  
Least Square ◽  
Model Parameters ◽  
Drilling Fluids ◽  
Cleaning Efficiency ◽  
Rheological Models ◽  
Least Square Regression ◽  
Best Fit

Appropriate selection of rheological models is important for hydraulic calculations of pressure loss prediction and hole cleaning efficiency of drilling fluids. Power law, Bingham-Plastic and Herschel-Bulkley models are the conventional fluid models used in the oilfield. However, there are other models that have been proposed in literature which are under/or not utilized in the petroleum industry. The primary objective of this paper is to recommend a rheological model that best-fits the rheological behaviour of xanthan gum-based biopolymer drill-in fluids for hydraulic evaluations. Ten rheological models were evaluated in this study. These rheological models have been posed deterministically and due to the unrealistic nature have been replaced by statistical models, by adding an error (disturbance) term and making suitable assumptions about them. Rheological model parameters were estimated by least-square regression method. Models like Sisko and modified Sisko which are not conventional models in oil industry gave a good fit. Modified Sisko model which is a four parameter rheological model was selected as the best-fit model since it produced the least residual mean square of 0.61 Ibf2/100ft4. There is 95% certainty that the true best-fit curve lies within the confidence band of this function of interest. Keywords: Biopolymer; Least-Square Regression; Residual Mean Squares; Rheologram

scholarly journals Industry 4.0 and University Performace Based on Prism Theory

2021 ◽  
Vol 2 (2) ◽  
pp. 065-091
Author(s):  
Tri Siwi Nugrahani ◽  
Yuni Nustini ◽  
Imanda Firmantyas Putri ◽  
Teguh Erawati
Keyword(s):  
Higher Education ◽  
Performance Appraisal ◽  
Industrial Revolution ◽  
National Standard ◽  
Education Standards ◽  
Organizational Assessment ◽  
Performance Achievement ◽  
Strategy Process ◽  
Level Of Satisfaction ◽  
Education Performance

This article aims to evaluate the performance of higher education based on the Higher Education National Standard (SN) which is implemented with the performance of Prisma. Prisma performance appraisal is able to assess the performance of all entities from various stakeholders including for universities in Indonesia. Every Prism performance appraisal goes through a satisfaction orientation, strategy, process, capability and contribution. Prism is very suitable for organizational assessment, especially in the era of the Industrial Revolution 4.0 because every aspect will always be related and affect performance achievement. Prism-based higher education performance studies by compiling Higher Education Standards can be used to add references as a measure of the level of satisfaction of stakeholders and can improve PT performance internally

scholarly journals Rutting Prediction Model of Asphalt Mixture Based on the Triaxial Repeated Load Test

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Jie Ji ◽  
Meng Chen ◽  
Zhi Suo ◽  
Jianming Wei ◽  
Jiani Wang ◽  
...  
Keyword(s):  
Prediction Model ◽  
Rheological Model ◽  
Asphalt Mixture ◽  
Load Test ◽  
Modified Asphalt ◽  
Load Tests ◽  
Repeated Load ◽  
Direct Coal Liquefaction ◽  
Coal Liquefaction Residue ◽  
Styrene Butadiene

This study establishes a more reasonable and effective rutting prediction model called the quadratic modified Burgers rheological model by considering dynamic loads. Use ABAQUS to simulate the rutting depths through the existing Burgers model and the quadratic modified model and compare with the measured values of the multitemperature and load rutting tests and triaxial repeated load tests. The real tests were conducted on four asphalt mixtures, including SK-90 asphalt mixture, styrene-butadiene-styrene (SBS) modified asphalt mixture, direct coal liquefaction residue (DCLR) modified asphalt mixture, and compound DCLR modified asphalt mixture. The results showed that the range of error ratio and residual sum of squares between simulated and measured rutting depth based on the two different models are 5–35%/5.0–8.74% and 3–15%/0.9–3.1%, respectively, which show that the quadratic modified Burgers rheological model has a more accurate prediction.

Three-Dimension Rheological Model and Parameters Solving for Unsaturated Soil

2011 ◽  
Vol 368-373 ◽  
pp. 2698-2701
Author(s):  
Guan Feng Tian
Keyword(s):  
Unsaturated Soil ◽  
Rheological Model ◽  
Model Parameters ◽  
Time Varying ◽  
Three Dimension ◽  
Confined Compression ◽  
Total Stress ◽  
Vertical Strain ◽  
Analytic Expressions ◽  
Rheological Test

Based on the three-dimension rheological model for unsaturated soil the constitutive equations are deduced by Laplace transformation. Then the time-dependent analytic expressions of vertical strain and lateral total stress in confined compression situation are also obtained. The modified confined rheological test has been carried out to get time-varying data of vertical strain and lateral total stress. Thus all the model parameters in the constitutive model can be calculated by the methods of curve fitting and formula inversion. At last, the method of the parameters solving is proved reasonable by an example.

scholarly journals Investigation of Nonlinear Creep Behaviour of Millettia Laurentii Wood Through Zener Fractional Rheological model

2021 ◽  
Author(s):  
Atchounga Kuida Prisca ◽  
Njankouo Jacques Michel ◽  
Foadieng Emmanuel ◽  
Talla Pierre Kisito
Keyword(s):  
Sensitivity Analysis ◽  
Rheological Model ◽  
Creep Behaviour ◽  
Research Work ◽  
Creep Process ◽  
Model Parameters ◽  
Structural Development ◽  
Nonlinear Creep ◽  
Deformation Amount ◽  
Creep Constitutive Model

Abstract Nowadays one of the principal difficulties that wood structural development and construction have to face is wood creep. Nevertheless, the secret to master and solve the creep deformation of wood relies on a sensible and exact rheological model for numerical analysis. In this research work our goal is to study the nonlinear creep behaviour of the Cameroonian wood species Millettia Laurentii known as Wengé wood through fractional calculus approach. So, we have conducted a nonlinear creep constitutive model of Millettia Laurentii wood, that is the Zener fractional rheological model, and the parameters of this model have been determined. We have studied the influence of stress level σ and fractional order n on the Millettia Laurentii wood creep process by a sensitivity analysis of the model parameters. The outcomes of this sensitivity analysis are of paramount importance because they can be used in reality to inspect the creep process and deformation amount of Millettia Laurentii wood in practical engineering. Moreover, guidance for the secure construction of Millettia Laurentii wood engineering can be given by the means of the findings of this research.

scholarly journals A Novel Simple Approach to Material Parameters from Commonly Accessible Rheometer Data

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1276 ◽  
Author(s):  
S. Schrüfer ◽  
D. Sonnleitner ◽  
G. Lang ◽  
D. W. Schubert
Keyword(s):  
Material Properties ◽  
Rheological Model ◽  
Melt Spinning ◽  
Polymeric Materials ◽  
Simple Approach ◽  
Model Systems ◽  
Model Parameters ◽  
Suitable Model ◽  
Starting Point ◽  
Wide Range

When characterizing the viscoelastic properties of polymers, shear rheological measurements are commonly the method of choice. These properties are known to affect extrusion and nozzle-based processes such as fiber melt spinning, cast film extrusion and 3D-printing. However, an adequate characterization of shear thinning polymers can be challenging and still insufficient to not only describe but predict process relevant influences. Furthermore, the evaluation of rheological model systems in literature is mostly based on stress–relaxation experiments, which are rarely available for various polymeric materials. Therefore, a simple approach is presented, that can be used to evaluate and benchmark a wide range of rheological model systems based on commonly accessible frequency sweep data. The approach is validated by analyzing alginate PH176 solutions of various concentrations, a thermoplastic poly-urethane (TPU) Elastollan 1180A melt, the liquid silicon rubber Elastosil 7670 and a polycaprolactone (PCL) fiber-alginate composite system. The used rheological model systems, consisting of simple springs and dashpots, are suitable for the description of complex, viscoelastic material properties that can be observed for polymer solutions and gel-like systems. After revealing a suitable model system for describing those material properties, the determination and evaluation of relevant model parameters can take place. We present a detailed guideline for the systematic parameter revelation using alginate solutions of different concentrations as example. Furthermore, a starting point for future correlations of strut spreading in 3D-bioprinting and model parameters is revealed. This work establishes the basis for a better understanding and potential predictability of key parameters for various fabrication techniques.

scholarly journals THE LOAD-DISPLACEMENT BEHAVIOUR OF GROUND ANCHORS IN FINE GRAINED SOILS

2018 ◽  
Vol 16 ◽  
pp. 18
Author(s):  
Juraj Chalmovský ◽  
Lumír Míča
Keyword(s):  
Load Transfer ◽  
Progressive Failure ◽  
Back Analysis ◽  
Material Model ◽  
Experimental Program ◽  
Structural Element ◽  
Fine Grained ◽  
Ground Anchors ◽  
Load Tests ◽  
Transfer Method

Ground anchors represent an important structural element in the area of geotechnical engineering. Despite their extensive usage, a design process of these elements is usually performed using simple empirical and semi-empirical methods, neglecting several important influencing factors. This paper gives an analysis of the factor of non-uniform distribution of skin friction resulting in a progressive failure of ground anchors. First, the finite element method in combination with a material model involving regularized strain softening is utilized. Next, an experimental program, including several investigation anchor load tests, was carried out. The goal of this program was to confirm preliminary conclusions drawn from numerical studies and to obtain relevant data for further back analysis. After, there is then described a newly developed application based on the load transfer method, in which all the findings from numerical computations and experimental measurements are incorporated.

Investigations on the dynamic behavior of a small-diameter pile driven in soft clay

2009 ◽  
Vol 46 (12) ◽  
pp. 1418-1430 ◽  
Author(s):  
Antonio M.L. Alves ◽  
Francisco R. Lopes ◽  
Mark F. Randolph ◽  
Bernadete R. Danziger
Keyword(s):  
Dynamic Behavior ◽  
Research Program ◽  
Dynamic Load ◽  
Dynamic Models ◽  
Soft Clay ◽  
Small Diameter ◽  
Model Parameters ◽  
Model Pile ◽  
Clear Distance ◽  
Load Tests

This paper presents results and analyses of the dynamic behavior of a small-diameter pile driven in very soft clay, with its tip embedded to a depth of 4.5 m with a clear distance of 1–1.5 m above a stiffer substratum. The research program included static and dynamic load tests performed over a period of 15 days, with blows from three different drop heights. The dynamic signals were analyzed using two different pile–soil interaction models. The performance of the dynamic models in predicting the shaft and base behavior of the model pile, as well as the change in bearing capacity and in some model parameters the dynamic with time, are addressed in particular.

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