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Academic literature on the topic 'ROUGHNESS OF MODEL PILES'

Author: Grafiati

Published: 11 September 2023

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Journal articles on the topic "ROUGHNESS OF MODEL PILES"

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Liu, Jun, Zhongwei Li, Guoliang Dai, and Weiming Gong. "Field Measurement and Theoretical Analysis of Sidewall Roughness on Shaft Resistance of Rock-Socketed Piles." Journal of Marine Science and Engineering 11, no. 8 (August 19, 2023): 1622. http://dx.doi.org/10.3390/jmse11081622.

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Sidewall roughness is a key factor influencing the shaft resistance of rock-socketed piles. Owing to the difficulties in onsite measuring and the inconsistency in quantitatively characterizing the roughness degree of sidewalls, existing approaches for estimating the shaft resistance of rock-socketed piles often cannot take this factor into account. Based on the measured surface curves of the 68 sockets in No. 6# and 7# group piles of the Chishi Bridge on the Ru-Chen Expressway in China, sidewall roughness is described by introducing the roughness factor (RF) based on the Horvath and Monash models, respectively, while a statistical analysis of the sidewall roughness in rock-socketed sections is also conducted. In addition, an analytical solution to the shaft resistance of rock-socketed piles with consideration of sidewall roughness and the relative settlement of the pile–rocks interface (∆s), is proposed and further compared with the field load tests. The results showed that: the RF obtained by the Horvath model is bigger than that obtained by the Monash model; the larger RF is, the bigger the mobilized shaft resistance; the analytical solution generally overestimates the mobilized shaft resistance of rock-socketed piles under the same ∆s, and the deviation is less than 15% if ∆s is larger than 3.00 mm. The Horvath model is recommended to quantitatively characterize the roughness degree of sidewalls for its good operability in practice.

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Alawneh, Ahmed Shlash, Abdallah I. Husein Malkawi, and Husein Al-Deeky. "Tension tests on smooth and rough model piles in dry sand." Canadian Geotechnical Journal 36, no. 4 (November 22, 1999): 746–53. http://dx.doi.org/10.1139/t98-104.

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In order to delineate the significant variables affecting the ultimate uplift shaft resistance of a pile in dry sand, a testing program comprising 64 pullout tests was conducted on open- and closed-ended rough and smooth model piles of two sizes (41 and 61 mm outside diameter). The model piles were installed in medium dense and dense sand to an embedded depth of 0.8 m using two methods of pile placement, static jacking and driving. A rigid steel box measuring 1.1 × 1.1 × 1.3 m was used as a sand container. The results obtained from this study indicated that pile placement method, initial sand condition, pile surface roughness, and pile end type are all significant variables (given in descending order) affecting the ultimate uplift shaft resistance of a single pile in dry sand. Overall, the closed-ended piles showed a 24% increase in shaft resistance compared with the open-ended piles and the average unit shaft resistance of the driven model pile was 1.33 times that of the jacked model pile in the dense sand condition and 1.52 times that of the jacked model pile in the medium dense sand condition. Depending on the test variables, the rough model piles tested in this study experienced a 12-54% increase in capacity compared with the smooth model piles. Also, the lateral earth pressure coefficient values for the rough model piles were greater than those for the smooth model piles. This suggests that part of the increase in capacity due to pile surface roughness is attributed to an increase in the radial effective stress during tensile loading.Key words: piles, shaft resistance, pile placement method, smooth pile, rough pile.

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Wang, Yan Qiang, Rui Gao, and Ya Wu Zeng. "Model Test of Roughness’ Influence on Bearing Mechanism in Rock-Socketed Pile." Advanced Materials Research 243-249 (May 2011): 3072–77. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.3072.

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The interface roughness between pile and rock in rock-socketed pile can influence its bearing mechanism largely. At present the numerical simulation, which simulates the interface roughness with changing the surface shape or interface friction coefficient, is used to study the interface roughness’ influence on pile’s bearing mechanism. It can reveal the pile bearing mechanism in some degree; however, there are some defects and limitations in simulation because of its assumptions and simplifications. Based on the pile foundation of Tian-xing-zhou Bridge, the model test is conducted to study the interface roughness’ influence on rock-socketed pile bearing mechanism. In the model test, the surface of model piles are made different ranging from smooth to rough, and the bed rock is simulated with mixture of sand and plaster, the rock-soil overlain the bed rock is simulated with silty sand, the pile is simulated with organic glass rod according to similarity principle respectively. The results show that load-settlement curves grow more gently, the ultimate bearing capacity is bigger, the proportion of point resistance is lower, and the shaft resistance is bigger which reaches more than 70% of total loading as the surface of pile is rougher. The conclusions are useful to deciding the length of pile foundation in Tian-xing-zhou Bridge.

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Subair, Aysar Hassan, and Ala Nasir Aljorany. "Shaft Resistance of Long (Flexible) Piles Considering Strength Degradation." Journal of Engineering 27, no. 3 (February 27, 2021): 54–66. http://dx.doi.org/10.31026/j.eng.2021.03.04.

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Soil-structure frictional resistance is an important parameter in the design of many foundation systems. The soil-structure interface area is responsible for load transferring from the structure to the surrounding soil. The mobilized shaft resistance of axially loaded, long slender pile embedded in dense, dry sand is experimentally and numerically analyzed when subjected to pullout force. Experimental setup including an instrumented model pile while the finite element method is used as a numerical analysis tool. The hypoplasticity model is used to model the soil adjacent to and surrounding the pile by using ABAQUS FEA (6.17.1). The soil-structure interface behavior depends on many factors, but mainly on the interface soil's tendency to contract or dilate under shearing conditions. To investigate this tendency, three piles with different surface roughness and under different confining pressures are used. A dilation behavior is observed in the relation of the average shaft resistance with the axial displacement for piles with rough and medium roughness surfaces, while contraction behavior is noticed when shearing piles with smooth surfaces. A large shear strength degradation of about (10%) reduction in the shaft resistance is observed under low confining pressure compared to a lesser reduction value of about (2%) under high confining pressure. Good agreement is obtained between the experimental and the numerical results.

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Muszyński, Zbigniew, and Marek Wyjadłowski. "Assessment of surface parameters of VDW foundation piles using geodetic measurement techniques." Open Geosciences 12, no. 1 (August 3, 2020): 547–67. http://dx.doi.org/10.1515/geo-2020-0042.

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AbstractThis article presents in situ research on the side surface of Vor der Wand (VDW) foundation piles using 3D laser scanning and close-range photogrammetry to assess the morphology of pile concrete surface. Contemporary analytical methods for estimation of the bearing capacity of the foundation pile surface require determination of the parameters of the concrete roughness and the model of the surface being formed, which corresponds to the pile technology used. Acquiring these data is difficult due to the formation of piles in the ground and their subsequent work as a structure buried in the ground. The VDW pile technology is one of the widespread technologies of foundation pile used in practice. These piles exhibit a specific configuration of the lateral surface, which is related to the simultaneous use of auger drilling and casing that rotates in opposite directions. Two geodetic techniques most often used to measure the geometry of buildings are terrestrial laser scanning and close-range photogrammetry. To empirically verify the suitability of these two techniques for describing the VDW pile surface parameters, a two-stage field study was performed. In the first stage, the measurements of concrete test surfaces were conducted. This surface was formed in a smooth formwork and its roughness parameters (in accordance with ISO 25178-2: 2012) were calculated and compared with the reference surface. In the second stage, measurements of the secant VDW sheet pile wall protecting the deep excavation were carried out. The roughness parameters of the pile surface were calculated for the selected areas in diverse geotechnical conditions. The original procedure for processing data (obtained using the above techniques) for assessment of roughness parameters of unique concrete surfaces was presented. The conducted research demonstrates that a pulse scanner has very limited usefulness for determination of roughness parameters for very smooth concrete surface; however, the photogrammetry techniques give acceptable results. In regard to the VDW pile surface, the results obtained from both measurement techniques give satisfactory consistency of the roughness parameters. The relative errors of calculated roughness parameters do not exceed 29% (average 12%). The proposed procedure may improve the accuracy of the assumed friction factor between pile surface and soil for assessment of the pile shaft bearing capacity for various pile technologies and soil conditions.

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Tovar-Valencia, Ruben D., Ayda Galvis-Castro, Rodrigo Salgado, and Monica Prezzi. "Effect of Surface Roughness on the Shaft Resistance of Displacement Model Piles in Sand." Journal of Geotechnical and Geoenvironmental Engineering 144, no. 3 (March 2018): 04017120. http://dx.doi.org/10.1061/(asce)gt.1943-5606.0001828.

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Bouafia, Ali. "Étude expérimentale du chargement latéral cyclique répété des pieux isolés dans le sable en centrifugeuse." Canadian Geotechnical Journal 31, no. 5 (October 1, 1994): 740–48. http://dx.doi.org/10.1139/t94-085.

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This paper presents the results of repetitive cyclic lateral loading test carried out in a centrifuge on two reduced models of single piles instrumented with strain gauges. The pile models, their instrumentation, the experimental setup, and the construction of the soil model are described. Effects of the pile surface roughness and of sand density on the pile behaviour are studied. The latest part of this paper deals with the construction of P–Y lateral reaction curves and the variation of the horizontal subgrade modulus with the number of cycles. Key words : pile, centrifuge, sand, cyclic loading, density, roughness.

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Khari, Mahdy, Khairul Anuar Kassim, and Azlan Adnan. "Development ofp-yCurves of Laterally Loaded Piles in Cohesionless Soil." Scientific World Journal 2014 (2014): 1–8. http://dx.doi.org/10.1155/2014/917174.

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The research on damages of structures that are supported by deep foundations has been quite intensive in the past decade. Kinematic interaction in soil-pile interaction is evaluated based on thep-ycurve approach. Existingp-ycurves have considered the effects of relative density on soil-pile interaction in sandy soil. The roughness influence of the surface wall pile onp-ycurves has not been emphasized sufficiently. The presented study was performed to develop a series ofp-ycurves for single piles through comprehensive experimental investigations. Modification factors were studied, namely, the effects of relative density and roughness of the wall surface of pile. The model tests were subjected to lateral load in Johor Bahru sand. The newp-ycurves were evaluated based on the experimental data and were compared to the existingp-ycurves. The soil-pile reaction for various relative density (from 30% to 75%) was increased in the range of 40–95% for a smooth pile at a small displacement and 90% at a large displacement. For rough pile, the ratio of dense to loose relative density soil-pile reaction was from 2.0 to 3.0 at a small to large displacement. Direct comparison of the developedp-ycurve shows significant differences in the magnitude and shapes with the existing load-transfer curves. Good comparison with the experimental and design studies demonstrates the multidisciplinary applications of the present method.

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GALLAS, JASON A. C., and STEFAN SOKOLOWSKI. "GRAIN NON-SPHERICITY EFFECTS ON THE ANGLE OF REPOSE OF GRANULAR MATERIAL." International Journal of Modern Physics B 07, no. 09n10 (April 20, 1993): 2037–46. http://dx.doi.org/10.1142/s0217979293002754.

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We use a site-site model to describe non-sphericity of particles composing a granular media. Specific effects of grain non-sphericity 011 the angle of repose are investigated. We report evidence indicating the possible existence of a shape-roughness threshold for grains: below it angles of repose are essentially the same as those obtained for spherical grains; above it there are pronounced changes 011 the angle of repose and it is possible to find rather large piles of grains.

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Aksoy, Huseyin Suha, Nichirvan Ramadhan Taher, Aykut Ozpolat, Mesut Gör, and Omer Muhammad Edan. "An Experimental Study on Estimation of the Lateral Earth Pressure Coefficient (K) from Shaft Friction Resistance of Model Piles under Axial Load." Applied Sciences 13, no. 16 (August 17, 2023): 9355. http://dx.doi.org/10.3390/app13169355.

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Estimating a pile shaft’s frictional capacity is challenging and has been a controversial subject among researchers. In this study, the shaft friction resistance of non-displacement (pre-installed) model piles under axial load was investigated. Four different model piles were used, including steel, timber, and two composite piles (FRP and PVC filled with concrete). The angle of interface friction (δ) between test sand, and pile materials was determined using an interface shear test (IST) at four relative densities. Axial pile load experiments were implemented in a soil tank and piles were embedded into loose to very dense sand. Model pile load tests were performed in such a way that there was no end (point) bearing capacity (only friction was generated), and lateral friction resistance between the pile material and the soil along the pile shaft formed the complete bearing capacity of the model pile. According to experimental results, it was observed that, with increasing sand relative density and surface roughness of the pile material, the shaft friction resistance of the model pile increases. A back-calculation analysis was also performed to find the values of lateral earth pressure coefficient (K) using Burland’s (1973) equation with the help of measured shaft friction capacity of the model pile load test. By performing multivariate regression analysis, an equation was obtained between the back-calculated lateral earth pressure coefficient (K) and other parameters. The obtained equation was used to calculate the K values given in other studies in the literature. It was determined that the obtained equation was in good agreement with the data in other studies. This equation can be beneficial in practice and can be advantageous for further study in the future.

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Dissertations / Theses on the topic "ROUGHNESS OF MODEL PILES"

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Nunez, Ian Louis. "Centrifuge model tension piles in clay." Thesis, University of Cambridge, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316783.

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Jacobson, Linnea, and Viktor Karlsson. "Design Model for Driven Concrete Piles According to Eurocode." Thesis, Linköpings universitet, Kommunikations- och transportsystem, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-118573.

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Pålning är en vanlig grundläggningsmetod för att överföra laster från överliggande konstruktioner genom svaga eller instabila jordlager till fasta jordlager eller berg. En typ av påle som ofta används är den slagna spetsburna betongpålen som slås ned genom till exempel lös lera till fast berg. 2011 trädde Eurokod in som gällande regelverk för dimensionering av bärverk. Införandet innebar förändringar i dimensionering av bland annat slagna spetsburna betongpålar. Företaget WSP i Norrköping har tidigare använt ett beräkningshjälpmedel för att få en uppfattning om en spetsburen betongpåles bärförmåga. Detta beräkningshjälpmedel blev i och med införandet av Eurokod inte längre giltigt. En önskan från WSP var att klargöra vad som gäller för dimensionering av spetsburna betongpålar enligt Eurokod och att ett nytt beräkningshjälpmedel skulle skapas om så var möjligt. När litteraturstudien för examensarbetet utfördes stod det klart att inget samlat dokument som beskrev alla delar av dimensionering av slagna spetsburna betongpålar fanns. Syftet med examensarbetet blev i och med det att sammanställa och tydliggöra gällande regelverk kring dimensionering av slagna spetsburna betongpålar. I den teoretiska referensramen sammanställs gällande regler och tillvägagångssätt för att utföra dimensioneringsberäkningar för en slagen spetsburen betongpåle. Det som sammanställts kan ses som ett förslag på hur dimensionering av en slagen spetsburen betongpåle kan genomföras. Resultatet visar att det är möjligt att skapa ett tillförlitligt beräkningsprogram som kan beräkna bärförmågan hos en spetsburen betongpåle enligt Eurokod. Vid jämförelsen av bärförmågan beräknad med det tidigare beräkningshjälpmedlet och det nya visade det sig att det nya ger en högre bärförmåga och framförallt ett noggrannare beräknat resultat.

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Sands, Timothy Bryan. "Interaction between model bored piles and swelling London clay." Thesis, University of Hertfordshire, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289605.

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Lopez, Sabater Carlos Joaquin. "An empirical model of hydraulic roughness for overland flow." Diss., The University of Arizona, 2001. http://hdl.handle.net/10150/280353.

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This research has developed a method for estimating hydraulic roughness coefficients for overland flow models in a dynamic approach, to more effectively simulate runoff on natural, agricultural and urban slopes. The hydraulic roughness coefficients are then generated with a series of neural networks. First, a laboratory experiment was designed to explore the effects of soil microtopography, slope and Reynolds number on the magnitude of Darcy-Weisbach, Manning and Chezy roughness coefficients. It was found that three parameters were necessary to describe the soil surface microtopography. Neural networks developed in a preliminary phase were able to reproduce the roughness coefficients obtained in the laboratory experiment by using five predictor variables: bed slope, Reynolds number, and the three parameters used to describe the microtopography. However, these networks failed to generate roughness coefficients for different input variables (generalization). Second, more complex algorithms were developed as combinations of neural networks in parallel. The algorithm output, the sought hydraulic roughness estimate, was estimated with the arithmetic average of the individual network outputs. Results presented in this study demonstrate that combining multiple neural networks reduced the prediction error and improved on the generalization ability of the neural networks. It was also observed that the estimate accuracy was influenced by the characteristics of the dataset, and especially by the relationship between the roughness coefficient and Reynolds numbers. Finally, a field experiment was performed to explore the applicability of the algorithms. A numerical model based on the 1-D diffusion approximation to the Saint Venant equations was constructed, and two surface irrigations were performed to collect data to test the model estimates. The model was used under two scenarios: (1) with constant hydraulic roughness coefficients, and (2) using variable hydraulic roughness predicted with the algorithm. Discharge at the end of the plot and irrigation front advance estimated using both models matched the observations well. However, when using a variable hydraulic roughness, the front was initially delayed until there was a sufficient surface storage to push it forward. The methodology described in this research should be useful for 2-D overland flow models applied to natural slopes with unsteady rainfall.

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Villeneuve, Joey. "Laboratory Testing for Adfreeze Bond of Sand on Model Steel Piles." Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/37323.

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This study explored the available adfreeze data published in literature and the techniques used to obtain it. Two methods were selected and modified to complete series of adfreeze bond test. A model pile pull-out method consisting of pulling a pile out a large specimen of soil was the first method used. The second method was modified from an interface shearing apparatus developed by Dr. Fakharian and Dr. Evgin at the University of Ottawa in 1996 and allowed preparing, freezing and testing the specimen in place. The material and soil tested for this study were provided by EXP Services Inc. The model pile, a galvanized HSS 114.3 x 8.6 section, is commonly used to install solar panels. Soil was taken from a future solar farm site in proximity to Cornwall, Ontario. The study had for objective to develop a low cost adfreeze laboratory testing method. Limitations of the technics and apparatus used were observed. While the results of a model pile pull-out test compared to previous data publish by Parameswaran (1978), the interface shear series of test presented more limitations. The interface shearing method has been previously study by Ladanyi and Thériault (1990). Issues with the interface shear method due to the water content of the soil as well as the range of normal stress applied to the specimen both during testing and freezing. The data obtained was inconclusive and the method will be studied in future research program. This studied approach the adfreeze testing with new improvement. The main contribution of this study is the data obtained by measuring and observing adfreeze of ice poor sand with varying water content. The measurements allowed to study the effect that increasing water content has on the interface bond strength. The modifications made to interface shear apparatus are also major new contribution provided by this research. The apparatus was converted in a small freezer chamber using insulation panel and vortex tubes. Which was used to freeze the specimen in the testing chamber and testing adfreeze in place without handling the shear box arrangement.

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Jeffrey, John. "Investigating the performance of continuous helical displacement piles." Thesis, University of Dundee, 2012. https://discovery.dundee.ac.uk/en/studentTheses/9877bf01-2251-4b34-aa8b-0ff9fc36a264.

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The Continuous Helical Displacement (CHD) pile is an auger displacement pile developed by Roger Bullivant Ltd in the UK. The CHD pile is installed in-situ through the use of a drilling auger, in a similar fashion to European screw piles and as such, it has performance characteristics of both displacement and non-displacement piles Based on field experience, it is known that the load capacity performance of the CHD pile significantly exceeds the current design predictions, particularly when installed in sand. Model CHD piles were created in pluviated test beds at a range of different densities and compared to model displacement and non-displacement piles. The load tests show that the CHD piles have a similar ultimate capacity to displacement piles. Instrumentation of the model piles allowed load distribution throughout the pile length to be determined. The tests allowed design parameters to be established, with it being shown that the CHD has lower bearing capacity factors and higher earth pressure coefficients than current suggestions .The disturbance to the in-situ soil conditions caused by the installation of the CHD piles was measured using a model CPT probe. The CHD pile was found to cause significant changes in soil relative density laterally around the pile shaft while displacement piles show changes predominantly below the pile base. The CHD pile is found to cause a densification of the in situ soil for all relative densities with the greatest increase occurring in loose sand. The ultimate capacity of the CHD pile is determined from load tests carried out on field CHD piles with the aid of capacity prediction methods for piles which have not been loaded to their ultimate capacity. The results from model testing have been applied to field pile tests to allow the development of design parameters including appropriate pile diameter, bearing capacity factor Nq and the earth pressure coefficient k which are suitable for CHD piles.

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Dapp, Steven Douglas. "Static Lateral Load Testing of Model Piles in Clay Soil Phase 1." DigitalCommons@USU, 2000. https://digitalcommons.usu.edu/etd/4544.

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This research project was done on behalf of the Utah Department of Transportation (UDOT). Model piles were subjected to static lateral loading in homogeneous, undisturbed clay with a known undrained shear strength. The dimensions of length, diameter, height from soil to applied load, and a pile stiffness parameter as was determined by dimensional analysis to be consistent will common full-scale steel pipe piles commonly used by UDOT. Bending moment profiles of the model pile were obtained for Lateral loads using foil type strain gages. Pile head deflection and soil response (p-y curves) were determined from these measured pile moment profiles. Model pile test results were compared to predictions made by the computer design packages Florida Pier (a 3-D, nonlinear, finite element analysis program written at the University of Florida) and COM624P.

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Nguyen, Van-Tri. "Thermal and thermo-mechanical behavior of energy piles." Thesis, Paris Est, 2017. http://www.theses.fr/2017PESC1160/document.

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Le comportement thermique et thermo-mécanique des pieux énergétiques est étudié par plusieurs approches : mesures au laboratoire sur des éprouvettes de sol, modélisation physique en modèle réduit, expérimentations sur pieu en vraie grandeur, et calculs numériques/analytiques. D’abord, la conductivité thermique d’un loess à l’état non saturé est mesurée en fonction de la teneur en eau et de la succion. Les résultats montrent une relation univoque entre la conductivité thermique et la teneur en eau pendant un cycle d’humidification/séchage alors qu’une boucle d’hystérésis est observée pour la relation entre la conductivité thermique et la succion. Deuxièmement, des essais thermiques sont réalisés sur un pieu énergétique expérimental en vraie grandeur pour étudier le transfert thermique à l’échelle réelle. Troisièmement, une solution analytique est proposée pour simuler la conduction thermique d’un pieu énergétique vers le sol environnant pendant un chauffage. Les tâches mentionnées ci-dessus concernant le comportant thermique sont ensuite complétées par des études sur le comportement thermo-mécanique des pieux énergétiques. D’un côté, des expérimentations sont réalisées sur un modèle réduit de pieu installé dans un sable sec ou dans une argile saturée. Trente cycles thermiques, représentant trente cycles annuels, sont appliqués au pieu sous différentes charges axiales en tête. Les résultats montrent un tassement irréversible avec les cycles thermiques ; ce tassement est plus important sous une charge axiale plus grande. De plus, le tassement est plus marqué pendant les premiers cycles thermiques et devient négligeable pour les cycles suivants. De l’autre côté, les travaux expérimentaux sur le modèle réduit de pieu sont complétés par les calculs numériques utilisant la méthode des éléments finis. Cette approche est d’abord validée avec les résultats obtenus sur le pieu modèle avant d’être utilisée pour prédire les résultats des expérimentations en vraie grandeur
The thermal and thermo-mechanical behavior of energy piles is investigated by various approaches: laboratory measurement on small soil samples, physical modeling on small-scale pile, experiments on real-scale pile, and analytical/numerical calculations. First, the thermal conductivity of unsaturated loess is measured simultaneously with moisture content and suction. The results show a unique relationship between thermal conductivity and moisture content during a wetting/drying cycle while a clear hysteresis loop can be observed on the relationship between thermal conductivity and suction. Second, thermal tests are performed on a full-scale experimental energy pile to observe heat transfer at the real scale. Third, an analytical solution is proposed to simulate conductive heat transfer from an energy pile to the surrounding soil during heating. The above-mentioned tasks related to the thermal behavior are then completed by studies on the thermo-mechanical behavior of energy piles. On one hand, experiments are performed on a small-scale pile installed either in dry sand or in saturated clay. Thirty thermal cycles, representing thirty annual cycles, are applied to the pile under various constant pile head loads. The results show irreversible pile head settlement with thermal cycles; the settlement is higher at higher pile head load. In addition, the irreversible thermal settlement is the most significant during the first cycles; it becomes negligible at high number of cycles. On the other hand, the experimental work with small-scale pile is completed with numerical calculations by using the finite element method. This approach is first validated with the results on small-scale pile prior to be used to predict the results of full-scale experiments

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Louw, Hendrik. "Modelling horizontally loaded piles in the geotechnical centrifuge." Diss., University of Pretoria, 2020. http://hdl.handle.net/2263/73182.

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Pile foundations are extensively used to support various structures that are constructed in soft/loose soils, where shallow foundations would be considered ineffective due to low bearing capacities and large settlements. The design of these structures to accommodate lateral applied loads in particular, usually imposed by winds, water and earth pressures, has gained popularity over the past few decades. The behaviour of horizontally loaded piled foundations is a complex soil-structure interaction problem and is usually concerned with the relative stiffness between the pile and the surrounding soil, where the relative stiffness is a function of both the stiffness and properties of the pile and the stiffness of the soil. Many design assumptions and methods used for pile foundations are based on the principles observed from metal piles. This raises the question of the validity and accuracy of assumptions and methods for the use of analysing and designing reinforced concrete piles, that exhibits highly non-linear material behaviour and changing pile properties after cracking. Due to the elastic behaviour of metal sections, these methods typically only focus on the soil component of the soil-structure interaction problem, only allowing changes and non-linear behaviour of the soil surrounding the pile to take place upon load application, mostly disregarding the behaviour and response of the pile itself. The main purpose and objective of the study was to determine whether aluminium sections in a centrifuge could be used to realistically and sufficiently accurately model the monotonic and cyclic response of reinforced concrete piles subjected to lateral loading. This was observed though a number of tests conducted in a geotechnical centrifuge on scaled aluminium and reinforced concrete piles, subjected to both monotonic and cyclic loading. After conducting the tests on both the scaled aluminium and reinforced concrete piles in the centrifuge it was concluded that aluminium sections cannot be used to accurately model and predict the lateral behaviour of reinforced concrete piles. Both the scaled aluminium and reinforced concrete piles proved to model the concept of laterally loaded piles quite well regarding bending at low loads. However, even at low lateral loads, the observed response of the scaled reinforced concrete was significantly different than that observed from the scaled aluminium pile. Furthermore, as the magnitude of the applied load and bending increased, the scaled reinforced concrete pile cracked, resulting in non-linear behaviour of the section under loading, which was not the case for the scaled aluminium pile that remained uncracked. This contributed to the difference in behaviour between the piles studied, therefore, the true material behaviour and failure mechanisms involved with reinforced concrete piles were not replicated by using a scaled aluminium pile section. The non-linear behaviour of the scaled reinforced concrete pile after cracking affected both the behaviour of the pile, as well as the response of the soil surrounding the pile, in contrast with the behaviour observed from the scaled aluminium pile.
Dissertation (MEng)--University of Pretoria, 2020.
The Concrete Institute
Concrete Society of Southern Africa
WindAfrica project
Civil Engineering
MEng (Structural Engineering)
Unrestricted

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Silveira, Mariana Vela. "Neuronal model for prediction of settlements in cintinua auger piles, metal and excavated." Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=12232.

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Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico
Estimar o recalque em estacas Ã um problema muito complexo, incerto e ainda nÃo totalmente compreendido, devido Ãs muitas incertezas associadas aos fatores que afetam a magnitude desta deformaÃÃo. As RNA sÃo ferramentas que funcionam analogamente ao cÃrebro humano, e sua unidade principal, o neurÃnio artificial, trabalha de maneira semelhante ao neurÃnio biolÃgico. Esta ferramenta alternativa vem sendo aplicada com sucesso em muitos problemas de engenharia geotÃcnica, podendo, portanto ser utilizadas como uma ferramentas alternativas para avaliar recalques em estacas isoladas. Nessa pesquisa as RNA utilizadas foram do tipo perceptron de mÃltiplas camadas, empregando um treinamento supervisionado utilizando o algoritmo de retropropagaÃÃo do erro. O modelo desenvolvido relaciona o recalque em estacas isoladas com as propriedades geomÃtricas das estacas (diÃmetro e comprimento), a estratigrafia e as caracterÃsticas de compacidade, ou consistÃncia dos solos por meio dos resultados obtidos nos ensaios SPT, e a carga atuante, obtidas em provas de carga realizadas em estacas hÃlice contÃnua, cravada metÃlica e escavada. O conjunto de aprendizagem foi composto por 1947 exemplos de entrada e saÃda. Com auxilio do programa QNET2000 foram treinadas e validadas vÃrias arquiteturas de redes neurais. ApÃs comparar o desempenho da curva carga x recalque elaborada com os recalques estimados pelo modelo proposto com a curva carga x recalque resultante da prova de carga estÃtica e com a curva carga x recalque gerada pelo emprego do programa comercial baseado em elementos finitos tridimensionais PLAXIS 3D Foundation, constatou-se que as RNA foram capazes de entender o comportamento das fundaÃÃes profundas do tipo estacas hÃlice contÃnua, escavada e cravada metÃlica, possibilitando dentre outras coisas, a definiÃÃo das cargas de trabalho e cargas limites nas estacas.
Predicting the settlement in deep foundation is a very complex, uncertain and not yet fully understood, due to the many uncertainties associated with factors that affect the magnitude of this deformation. Artificial Neural Network (ANN) is a tool that works similarly to the human brain, its main unit, the artificial neuron, works in a similar way to the biological neuron. This alternative tool has been successfully applied in many geotechnical engineering problems and can therefore be used as an alternative tool to evaluate the behavior of settlement in isolated piles. In this paper, the ANN used were the multilayer perceptron type, employing a supervised training that uses the error back propagation algorithm. The model developed relates settlement in isolated piles with the type and the geometrical properties of the piles (diameter and length), the stratigraphy and characteristics of compactness or consistency of soils by means of the SPT tests results, and the load applied, obtained in static pile load tests performed in continuous helix, steel driven and excavated pile types. The data set used to model consisted of 1.947 samples of input and output. QNET 2000 was the program used to assist the training and validation of various architectures of neural networks. The architecture formed by 10 nodes in the input layer, 28 neurons distributed in 4 intermediate layers and one neuron in the output layer, corresponding to the measured discharge for cutting (A10: 14:8:4:2:1) was the one that showed the best performance, with the correlation coefficient between the estimated settlements and settlements measured during the validation phase of 0.94, such value can be considered satisfactory when considering the prediction of a complex phenomenon. After comparing the performance of the applied load x settlement estimated by model proposed curve with the applied load x settlement measured in static pile load test curve and the applied load x settlement estimated by an elasto-plastic model thru numerical simulation, it was found that the ANN were able to understand the behavior of deep foundations of continuous helix, steel driven and excavated piles type, allowing among other things, the definition of workloads and load limits at the pile.

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Books on the topic "ROUGHNESS OF MODEL PILES"

1

Papagiannakis, A. T. A roughness model describing heavy vehicle-pavement interaction. [Olympia]: Washington State Dept. of Transportation, 1995.

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United States. Federal Highway Administration. and Atkinson-Noland & Associates., eds. Centrifugal testing of model piles and pile groups. McLean, Va: U.S. Dept. of Transportion, Federal Highway Administration, 1985.

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V, Vorburger T., and United States. National Bureau of Standards, eds. The Wind tunnel model surface gauge for measuring roughness. [Gaithersburg, MD: U.S. Dept. of Commerce, National Bureau of Standards, 1987.

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Hapke, Bruce. Applications of an energy transfer model to three problems in planetary regoliths: The solid-state greenhouse, thermal beaming, and emittance spectra. [Washington, DC: National Aeronautics and Space Administration, 1996.

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Bekbasarov, Isabay. Study of the process of driving piles and dies on models. ru: INFRA-M Academic Publishing LLC., 2020. http://dx.doi.org/10.12737/1074097.

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The monograph presents the results of experimental and theoretical studies conducted using models of driven piles and tape dies. The influence of the cross-section size, length, shape of the trunk and the lower end of the piles on their submergability, energy intensity of driving and load-bearing capacity was evaluated. The design and technological features of new types of piles are considered. A method for determining the load-bearing capacity of a pile model based on the results of dynamic tests has been developed. Similarity conditions and formulas are presented that provide modeling of the pile driving process in the laboratory. The influence of the shape of the tape dies on their submersibility, energy consumption of the driving and the bearing capacity of the foundations arranged in the vyshtampovannyh pits was evaluated. The method of determining the load-bearing capacity of a belt Foundation model based on the results of pit vyshtampovyvaniya is described. Recommendations on the choice of optimal parameters of piles and foundations, arranged in vystupovani pits. Recommended for researchers, specialists of design and construction organizations, doctoral students, postgraduates, undergraduates and students of construction and water management specialties.

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Harder, Markus. Dynamik, Rauhigkeit und Alter des Meereises in der Arktis: Numerische Untersuchungen mit einem grossskaligen Modell = Dynamics, roughness, and age of Arctic sea ice : numerical investigations with a large-scale model. Bremerhaven: Alfred-Wegener-Institut für Polar- und Meeresforschung, 1996.

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Lake, G. C. The development of shaft friction and end bearing resistance for dynamically-driven model piles. 1986.

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Yust, Jason. Structural Networks and the Experience of Musical Time. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780190696481.003.0005.

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The network model of temporal structure allows for many generalized concepts of musical time that can be applied across different modalities (rhythmic, tonal, and formal). This chapter defines network depths, distances, paths, centers, skew, and bias, and partially classifies network types such as piles, tortoises, and starfish. A splitting operation on networks is defined and applied to the problem of relating networks in different modalities and finding true disjunctions.

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McAdams, Stephen, and Bruno L. Giordano. The perception of musical timbre. Edited by Susan Hallam, Ian Cross, and Michael Thaut. Oxford University Press, 2012. http://dx.doi.org/10.1093/oxfordhb/9780199298457.013.0007.

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This article discusses musical-timbre perception. Musical timbre is a combination of continuous perceptual dimensions and discrete features to which listeners are differentially sensitive. The continuous dimensions often have quantifiable acoustic correlates. The timbre-space representation is a powerful psychological model that allows predictions to be made about timbre perception in situations beyond those used to derive the model in the first place. Timbre can play a role in larger-scale movements of tension and relaxation and thus contribute to the expression inherent in musical form. Under conditions of high blend among instruments composing a vertical sonority, timbral roughness is a major component of musical tension. However, it strongly depends on the way auditory grouping processes have parsed the incoming acoustic information into events and streams.

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Chan, Johnny C. L. Physical Mechanisms Responsible for Track Changes and Rainfall Distributions Associated with Tropical Cyclone Landfall. Oxford University Press, 2017. http://dx.doi.org/10.1093/oxfordhb/9780190676889.013.16.

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As a tropical cyclone approaches land, its interaction with the characteristics of the land (surface roughness, topography, moisture availability, etc.) will lead to changes in its track as well as the rainfall and wind distributions near its landfall location. Accurate predictions of such changes are important in issuing warnings and disaster preparedness. In this chapter, the basic physical mechanisms that cause changes in the track and rainfall distributions when a tropical cyclone is about to make landfall are presented. These mechanisms are derived based on studies from both observations and idealized simulations. While the latter are relatively simple, they can isolate the fundamental and underlying physical processes that are inherent when an interaction between the land and the tropical cyclone circulation takes place. These processes are important in assessing the performance of the forecast models, and hence could help improve the model predictions and subsequently disaster preparedness.

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Book chapters on the topic "ROUGHNESS OF MODEL PILES"

1

Hartung, M., K. Meier, and W. Rodatz. "Integrity testing on model piles." In Application of Stress-Wave Theory to Piles, 265–69. London: Routledge, 2022. http://dx.doi.org/10.1201/9781315137544-37.

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Tang, Chong, and Kok-Kwang Phoon. "Evaluation of Design Methods for Helical Piles." In Model Uncertainties in Foundation Design, 457–518. First edition. | Boca Raton : CRC Press, 2021.: CRC Press, 2021. http://dx.doi.org/10.1201/9780429024993-8.

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Iskander, Magued. "Similitude between Model and Full Scale Piles." In Springer Series in Geomechanics and Geoengineering, 187–94. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-13108-0_8.

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Helfrich, W., and B. Klösgen. "Adhesion and Roughness of Biological Model Membranes." In Springer Proceedings in Physics, 2–18. Berlin, Heidelberg: Springer Berlin Heidelberg, 1990. http://dx.doi.org/10.1007/978-3-642-76008-2_1.

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McKeon, Beverley J. "Turbulent Channel Flow over Model “Dynamic” Roughness." In IUTAM Symposium on The Physics of Wall-Bounded Turbulent Flows on Rough Walls, 87–92. Dordrecht: Springer Netherlands, 2010. http://dx.doi.org/10.1007/978-90-481-9631-9_12.

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Trung, Do Duc, Trinh Kieu Tuan, Tran Quoc Hoang, Nguyen Van Tuan, and Luu Anh Tung. "Surface Roughness Model When Grinding 1066 Steel." In Advances in Engineering Research and Application, 897–908. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-92574-1_92.

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Englan, M. "Pile settlement behaviour: An accurate model." In Application of Stress-Wave Theory to Piles, 695. London: Routledge, 2022. http://dx.doi.org/10.1201/9781315137544-104.

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England, M. "Pile settlement behaviour: An accurate model." In Application of Stress-Wave Theory to Piles, 91–97. London: Routledge, 2022. http://dx.doi.org/10.1201/9781315137544-13.

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Liang, R. Y., and Yangjing Sheng. "Theoretical interpretation of Smith′ model parameters." In Application of Stress-Wave Theory to Piles, 111–16. London: Routledge, 2022. http://dx.doi.org/10.1201/9781315137544-16.

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Hadi, Yasir, and Salah Gasim Ahmed. "Assessment of Surface Roughness Model for Turning Process." In IFIP International Federation for Information Processing, 152–58. Boston, MA: Springer US, 2006. http://dx.doi.org/10.1007/0-387-34403-9_19.

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Conference papers on the topic "ROUGHNESS OF MODEL PILES"

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Kullolli, Borana, Matthias Baeßler, Pablo Cuéllar, Shilton Rica, and Frank Rackwitz. "An Enhanced Interface Model for Friction Fatigue Problems of Axially Loaded Piles." In ASME 2019 38th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/omae2019-96078.

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Abstract The shaft bearing capacity often plays a dominant role for the overall structural behaviour of axially loaded piles in offshore deep foundations. Under cyclic loading, a narrow zone of soil at the pile-soil interface is subject to cyclic shearing solicitations. Thereby, the soil may densify and lead to a decrease of confining stress around the pile due to micro-phenomena such as particle crushing, migration and rearrangement. This reduction of radial stress has a direct impact on the shaft capacity, potentially leading in extreme cases to pile failure. An adequate interface model is needed in order to model this behaviour numerically. Different authors have proposed models that take typical interface phenomena in account such as densification, grain breakage, normal pressure effect and roughness. However, as the models become more complex, a great number of material parameters need to be defined and calibrated. This paper proposes the adoption and transformation of an existing soil bulk model (Pastor-Zienkiewicz) into an interface model. To calibrate the new interface model, the results of an experimental campaign with the ring shear device under cyclic loading conditions are here presented. The constitutive model shows a good capability to reproduce typical features of sand behaviour such as cyclic compaction and dilatancy, which in saturated partially-drained conditions may lead to liquefaction and cyclic mobility phenomena.

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Tovar-Valencia, Ruben D., Ayda Galvis-Castro, Monica Prezzi, and Rodrigo Salgado. "Effect of Surface Roughness on the Tensile and Compressive Shaft Resistance of Displacement Model Piles in Sand." In International Foundations Congress and Equipment Expo 2021. Reston, VA: American Society of Civil Engineers, 2021. http://dx.doi.org/10.1061/9780784483404.013.

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Raju, Devika. "AN EXPERIMENTAL INVESTIGATION ON BEHAVIOUR OF TIMBER PILE GROUPS IN SANDY SOIL." In International Conference on Innovations in Computing Materials & Communication Technologies. San International Scientific Publications, 2023. http://dx.doi.org/10.59646/proceedings/003.

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Pile raft foundation is relatively new approach for design of pile group in which pile cap was considered in contact with soil and designed as raft that transfer partial load of superstructure to soil. The design of pile raft foundation is no t a simple problem as many interaction effect as pile to pile, pile to soil, pile to raft and raft to soil are involved and effect the design considerable. In this study, an experimental investigation has been carried out on a sufficiently large model in laboratory to observe the effect of various parameters such as effect on load carrying capacity of pile raft on diameter, length of pile, pile surface roughness, relative density of sand. A Timber piles can also be driven for ground improvement, to densify loose granular soils.

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4

Ainola, Leo, Tiit Koppel, Kalle Tiiter, and Anatoli Vassiljev. "Water Network Model Calibration Based on Grouping Pipes with Similar Leakage and Roughness Estimates." In Joint Conference on Water Resource Engineering and Water Resources Planning and Management 2000. Reston, VA: American Society of Civil Engineers, 2000. http://dx.doi.org/10.1061/40517(2000)197.

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Hartloper, C., K. K. Botros, J. Geerligs, H. Golshan, and K. Jensen. "Measurements and Evaluation of Internal Wall Surface Roughness of Small Diameter Pipes for High Pressure Natural Gas Systems." In 2014 10th International Pipeline Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/ipc2014-33019.

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The default roughness parameter values used in industry to determine the pressure loss through small diameter pipeline systems are much higher than the values employed in typical large diameter gas transmission and lateral systems. It is uncertain whether these higher roughness values are due to higher topological roughness of the internal wall of the small diameter pipes or if they are a result of other factors. Measurements were taken on 17 small diameter pipe samples in order to evaluate the pipe-wall roughness parameter. A model to calculate the effective roughness parameter, which takes into account pressure losses due to the measured roughness as well as internal welds and scaling, has been developed. The effective roughness parameter of these samples is found to range from 20.4μm to 62.9μm, an increase of 11.0μm to 23.3μm over the measured pipe-wall roughness parameter. This range of effective roughness parameters agrees well with the default range of 35μm to 65μm used in industry, as well as the literature quoted range for clean pipe of 40μm to 100μm. The measured roughness parameter on average increases with increasing nominal pipe size, a result that may be a characteristic of the extrusion or hot-rolling processes used to manufacture small diameter pipes. Additionally, there is a large variation in the measured roughness parameters of pipe samples of the same nominal pipe size, indicating that surface roughness can vary depending on the manufacturing source of these pipes.

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Ebadi, Adel, Zohreh Mansoori, Majid Saffar-Avval, and Goodarz Ahmadi. "Wall Roughness Effect on Heat Transfer Rate of the Turbulent Gas-Solid Flow in Inclined Pipes." In ASME 2014 4th Joint US-European Fluids Engineering Division Summer Meeting collocated with the ASME 2014 12th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/fedsm2014-21778.

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The effects of wall surface roughness on the rate of heat transfer and temperature profiles in turbulent gas-solid flows in pipes at different inclination angles were studied. The earlier developed computational model for 3D flows including the four-way interactions was extended and used in this study for evaluating the mean flow, turbulence intensity and thermal fields. Interaction of particles with the rough wall was included by introducing the available stochastic wall roughness models (shadow effect model) for the dispersed phase in the computational program. It was found that changes in the particle dispersion and particle concentration altered the Nusselt number and heat transfer rate in different regions of the pipe. The Nusselt number decreased in the lower part of the duct for horizontal and inclined pipes due to the reduction in the settling velocity. The surface roughness also altered the heat transfer coefficient in the periphery of the vertical riser. The simulation results showed that the fluid temperature was reduced in the pipe core and increased near the wall region for inclined pipes. On the other hand, particle temperature increased and flattened in the entire pipe cross section.

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Bhatt, Chinmay P., and Stephen T. McClain. "Assessment of Uncertainty in Equivalent Sand-Grain Roughness Methods." In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-42105.

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The equivalent sand-grain roughness model is an empirical model initiated by Schlichting for predicting skin friction and heat transfer for turbulent flows over rough surfaces. For the equivalent sand-grain roughness model, rough surfaces with various features are compared to data from Nikuradse concerning flow in pipes with varying sizes of sieved sand glued to the wetted surface. Rough surfaces are assigned a value of equivalent sand-grain roughness height based on comparisons with Nikuradse’s fully rough data. Recent literature on the equivalent sand-grain roughness method has involved seeking correlations for equivalent sand-grain roughness height based on roughness metrics such as height, shape, and density. The Sigal-Danberg parameter has demonstrated the most promise for correlating the available equivalent roughness height data to geometric surface information. The Sigal-Danberg parameter was recently modified to include the mean surface elevation as an important parameter. While the modified Sigal-Danberg parameter provides a unified correlation for the equivalent sand-grain roughness height, the new formulation does not improve the scatter of the experimental data around the correlation. An uncertainty analysis is presented to evaluate the uncertainty of equivalent sand-grain roughness height predictions using the unified correlation. The analysis begins by estimating the uncertainties in the experimental measurements of Schlichting, and the uncertainty propagation is evaluated through each step of the equivalent sand-grain method development. The uncertainty associated with using empirical equations and conceptual uncertainties not associated with experimental measurements are also discussed. The result is an improved understanding of and uncertainty quantification for skin friction and heat transfer predictions made using equivalent sand-grain roughness methods.

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8

Awad, M. M., and Y. S. Muzychka. "A Simple Asymptotic Compact Model for Two-Phase Frictional Pressure Gradient in Horizontal Pipes." In ASME 2004 International Mechanical Engineering Congress and Exposition. ASMEDC, 2004. http://dx.doi.org/10.1115/imece2004-61410.

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A simple semi-theoretical method for calculating two-phase frictional pressure gradient in horizontal pipes using asymptotic analysis is presented. Two-phase frictional pressure gradient is expressed in terms of the asymptotic single-phase frictional pressure gradients for liquid and gas flowing alone. The proposed model uses an asymptotic correlation method to develop a robust compact model. The proposed model can be transformed into either a two-phase frictional multiplier for liquid flowing alone (φl2) or two-phase frictional multiplier for gas flowing alone (φg2) as a function of the Lockhart-Martinelli parameter, X. Single phase friction factors are calculated using the Churchill model which allows for prediction over the full range of laminar-transition-turbulent regions and to allow for pipe roughness effects. The proposed model is compared against published data for a number of pipe diameters. Effect of mass flux on two-phase frictional pressure gradient is also investigated. Comparison with other existing correlations for two-phase frictional pressure gradient such as the Chisholm correlation, the Friedel correlation, and the Mu¨ller-Steinhagen and Heck correlation, is also presented. Comparison with other existing correlations and experimental data for both φl and φg versus X is also presented.

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9

Pisarenco, Maxim, Bas van der Linden, Arris Tijsseling, Emmanuel Ory, and Jacques Dam. "Friction Factor Estimation for Turbulent Flows in Corrugated Pipes With Rough Walls." In ASME 2009 28th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/omae2009-79854.

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The motivation of the investigation is critical pressure loss in cryogenic flexible hoses used for LNG transport in offshore installations. Our main goal is to estimate the friction factor for the turbulent flow in this type of pipes. For this purpose, two-equation turbulence models (k–ε and k–ω) are used in the computations. First, fully developed turbulent flow in a conventional pipe is considered. Simulations are performed to validate the chosen models, boundary conditions and computational grids. Then a new boundary condition is implemented based on the “combined” law of the wall. It enables us to model the effects of roughness (and maintain the right flow behavior for moderate Reynolds numbers). The implemented boundary condition is validated by comparison with experimental data. Next, turbulent flow in periodically corrugated (flexible) pipes is considered. New flow phenomena (such as flow separation) caused by the corrugation are pointed out and the essence of periodically fully developed flow is explained. The friction factor for different values of relative roughness of the fabric is estimated by performing a set of simulations. Finally, the main conclusion is presented: the friction factor in a flexible corrugated pipe is mostly determined by the shape and size of the steel spiral, and not by the type of the fabric which is wrapped around the spiral.

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10

Ghasvari-Jahromi, H., Gh Atefi, A. Moosaie, and S. Hormozi. "Analytical Solution of Turbulent Problems Using Governing Equation of Cosserat Continuum Model." In ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-15837.

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In present paper the theory of the micropolar fluid based on a Cosserat continuum model has been applied for analysis of Couette flow and turbulent flow through rough pipes. The obtained results for the velocity field have been compared with known results from experiments done by Reichardt at Max Plank institute for fluids in Gottingen [1,2] and analytical solution of the problem from Gradient theory by alizadeh[3] for couette problem and with known results from experiments done by Nikuradse (1932). the boundary condition used here was the no slip one and Trostel's slip boundary condition[4].a good agreement between experimental results and the results of the problem for Reynolds near 18000 has beeen found in the couette case also in this case A new dimensionless number introduced that indicates the theoretical relation between cosserat theory and slip theory and their interaction. The solution has been performed for a Reynolds number of 106 for pipes with different values of roughness and the validity analysis approved by the results of Nikuradse's experiments.

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Reports on the topic "ROUGHNESS OF MODEL PILES"

1

Brown, Gary S. A New Composite Roughness Surface Scattering Model. Fort Belvoir, VA: Defense Technical Information Center, January 1992. http://dx.doi.org/10.21236/ada248891.

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Brown, Gary S. A New Composite Roughness Surface Scattering Model. Fort Belvoir, VA: Defense Technical Information Center, January 1992. http://dx.doi.org/10.21236/ada249810.

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3

Vorburger, T. V., D. E. Gilsinn, E. C. Teague, C. H. W. Giauque, F. E. Scire, and L. X. Cao. The wind tunnel model surface gauge for measuring roughness. Gaithersburg, MD: National Bureau of Standards, 1987. http://dx.doi.org/10.6028/nbs.ir.87-3586.

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4

Bane, Karl LF. The Resonator Impedance Model of Surface Roughness Applied to the LCLS Parameters. Office of Scientific and Technical Information (OSTI), March 1999. http://dx.doi.org/10.2172/9892.

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Hitney, Herbert V. An Approximate Model for Vertical Polarization and Surface Roughness Using the Parabolic Equation. Fort Belvoir, VA: Defense Technical Information Center, March 1994. http://dx.doi.org/10.21236/ada278091.

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Styles, Richard, Scott Glenn, and Mitchell Brown. An optimized combined wave and current bottom boundary layer model for arbitrary bed roughness. Coastal and Hydraulics Laboratory (U.S.), July 2017. http://dx.doi.org/10.21079/11681/22734.

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Jackson, Darrell R., Paul D. Ingalis, and Kou-Ying Moravan. 100 Hz-10 kHz Bottom Backscattering Model: Generalized Treatment of Sediment Sound Propagation, Sediment Volume Scattering, and Interface-Roughness Scattering. Fort Belvoir, VA: Defense Technical Information Center, April 1994. http://dx.doi.org/10.21236/ada291323.

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Lei, Jiangtao, Marcos Arroyo, Matteo Ciantia, and Ningning Zhang. Grain roughness effect on the critical state line of crushable sands. University of Dundee, December 2021. http://dx.doi.org/10.20933/100001234.

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A recently proposed DEM model for materials with rough crushable grains (Zhang et al. 2021; Ciantia et al. 2015; Otsubo et al. 2017) is here employed to examine the effect of contact roughness on the critical state line, a property of granular materials which is a) fundamental for the evaluation of liquefaction risk and liquefied responses and b) easily accessible through DEM simulation (Ciantia et al. 2019).

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McKnight, C., David May, and Keaton Jones. Numerical analysis of dike effects on the Mississippi River using a two-dimensional Adaptive Hydraulics model (AdH). Engineer Research and Development Center (U.S.), November 2022. http://dx.doi.org/10.21079/11681/46120.

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This report describes the hydraulic effects of dikes on water surface elevation (WSE) and velocities in the Mississippi River near Vicksburg, MS, from Interstate 20 to Highway 80 using a previously calibrated 2D Adaptive Hydraulics numerical model. Dike heights and their associated hydraulic roughness values were varied to quantify the overall effects of adjustments to dike fields. Steady flows characterized as low, medium, and high conditions were simulated. The WSE and velocity difference plots were generated to illustrate the hydraulic effects on the river under all scenarios discussed above. Overall, the dike adjustments had negligible impacts on WSEs and showed minimal effects on velocities on a system-wide scale.

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Agassi, Menahem, Michael J. Singer, Eyal Ben-Dor, Naftaly Goldshleger, Donald Rundquist, Dan Blumberg, and Yoram Benyamini. Developing Remote Sensing Based-Techniques for the Evaluation of Soil Infiltration Rate and Surface Roughness. United States Department of Agriculture, November 2001. http://dx.doi.org/10.32747/2001.7586479.bard.

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The objective of this one-year project was to show whether a significant correlation can be established between the decreasing infiltration rate of the soil, during simulated rainstorm, and a following increase in the reflectance of the crusting soil. The project was supposed to be conducted under laboratory conditions, using at least three types of soils from each country. The general goal of this work was to develop a method for measuring the soil infiltration rate in-situ, solely from the reflectance readings, using a spectrometer. Loss of rain and irrigation water from cultivated fields is a matter of great concern, especially in arid, semi-arid regions, e.g. much of Israel and vast area in US, where water is a limiting factor for crop production. A major reason for runoff of rain and overhead irrigation water is the structural crust that is generated over a bare soils surface during rainfall or overhead irrigation events and reduces its infiltration rate (IR), considerably. IR data is essential for predicting the amount of percolating rainwater and runoff. Available information on in situ infiltration rate and crust strength is necessary for the farmers to consider: when it is necessary to cultivate for breaking the soil crust, crust strength and seedlings emergence, precision farming, etc. To date, soil IR is measured in the laboratory and in small-scale field plots, using rainfall simulators. This method is tedious and consumes considerable resources. Therefore, an available, non-destructive-in situ methods for soil IR and soil crusting levels evaluations, are essential for the verification of infiltration and runoff models and the evaluation of the amount of available water in the soil. In this research, soil samples from the US and Israel were subjected to simulated rainstorms of increasing levels of cumulative energies, during which IR (crusting levels) were measured. The soils from the US were studied simultaneously in the US and in Israel in order to compare the effect of the methodology on the results. The soil surface reflectance was remotely measured, using laboratory and portable spectrometers in the VIS-NIR and SWIR spectral region (0.4-2.5mm). A correlation coefficient spectra in which the wavelength, consisting of the higher correlation, was selected to hold the highest linear correlation between the spectroscopy and the infiltration rate. There does not appear to be a single wavelength that will be best for all soils. The results with the six soils in both countries indeed showed that there is a significant correlation between the infiltration rate of crusted soils and their reflectance values. Regarding the wavelength with the highest correlation for each soil, it is likely that either a combined analysis with more then one wavelength or several "best" wavelengths will be found that will provide useful data on soil surface condition and infiltration rate. The product of this work will serve as a model for predicting infiltration rate and crusting levels solely from the reflectance readings. Developing the aforementioned methodologies will allow increased utilization of rain and irrigation water, reduced runoff, floods and soil erosion hazards, reduced seedlings emergence problems and increased plants stand and yields.

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