Letteratura scientifica selezionata sul tema "Passive Piles"
Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili
Consulta la lista di attuali articoli, libri, tesi, atti di convegni e altre fonti scientifiche attinenti al tema "Passive Piles".
Accanto a ogni fonte nell'elenco di riferimenti c'è un pulsante "Aggiungi alla bibliografia". Premilo e genereremo automaticamente la citazione bibliografica dell'opera scelta nello stile citazionale di cui hai bisogno: APA, MLA, Harvard, Chicago, Vancouver ecc.
Puoi anche scaricare il testo completo della pubblicazione scientifica nel formato .pdf e leggere online l'abstract (il sommario) dell'opera se è presente nei metadati.
Articoli di riviste sul tema "Passive Piles"
1
Hanna, A. M., and A. Afram. "Pull-out capacity of single batter piles in sand." Canadian Geotechnical Journal 23, no. 3 (1986): 387–92. http://dx.doi.org/10.1139/t86-054.
Testo completoAbstract (sommario):
The pull-out capacity of single rigid vertical and batter piles in sand and subjected to axial loading has been investigated. Good agreement was found when test results on instrumented model piles were compared with theoretical estimates. The effect of pile inclination on the pull-out capacity has been explained by means of variable mobilized passive earth pressure on the pile's perimeter. A design method and charts are presented. Key words: pile foundation, pull-out capacity, vertical pile, batter pile, sand–soil mechanics.
2
Zhou, Dequan, Qin Zhu, and Chuangye Wang. "Experimental Investigation on Performances of Battered Piles Resisting Embankment-Induced Lateral Soil Movement." Applied Sciences 13, no. 18 (2023): 10333. http://dx.doi.org/10.3390/app131810333.
Testo completoAbstract (sommario):
The performance of passive battered piles resisting the embankment-induced lateral soil movements may differ from that of the active battered pile and axially loaded existing vertical piles adjacent to embankment constructions. This study was part of a preliminary feasibility investigation for a reinforcement plan of an actual embankment project, aiming to experimentally investigate the performance of passive battered piles under embankment-induced lateral soil movement. To this end, a sequence of reduced-scale model tests of battered piles near the surcharges was first designed in sandy soil with a similarity ratio of 1:30. The effects of pile inclinations (β = −20°, −10°, 0°, +10°, and +20°), surcharge magnitudes, and constraint conditions at the pile tip (free-tip and fixed-tip) on the responses of passive battered piles were explored. Finally, the response characteristics of battered piles resisting the embankment-induced lateral soil movement were analyzed to clarify the working mechanism of these battered piles.
3
Ren, Xiang, Lijuan Luo, Yunxin Zheng, Jiakuan Ma, and Xuexu An. "Morphological Evolution of Passive Soil Arch in Front of Horizontal Piles in Three Dimensions." Buildings 12, no. 7 (2022): 1056. http://dx.doi.org/10.3390/buildings12071056.
Testo completoAbstract (sommario):
The anti-slide pile is a primary method of landslide control. The effect of the passive soil arch in front of the embedded section of piles has a significant effect on the anti-slide pile’s bearing capacity. The upgraded model test scheme was used to conduct model tests with a pile spacing four times the width of the pile and a geometric scale ratio of 1:15. The anti-slide pile stress, pile bending strain, and soil stress in front of the pile were all studied in relation to the loading amount. In addition to the model test, the numerical simulation method was utilized to investigate the three-dimensional morphological change of the passive soil arch in front of the pile. The results indicated that: clearly, the side piles can eliminate the border effect. The distribution of pile bending strain along the pile after loading is referred to as a parabola. Bending failure occurred at a depth of 40 mm, approximately 0.9 m from the pile top. Under the condition that the pile spacing is four times the pile width, a passive soil arch occurs in front of the anti-slide pile’s fixed part, and its development can be split into four stages: formation, development, completion, and destruction. The passive soil arches in front of the piles are generated and destroyed gradually along the buried depth, and the three-dimensional surface of the space drops gradually along the buried depth with the loading amount and advances toward the loading direction until the anti-slide pile system fails. The research findings and experiences can serve as a basis for future research.
4
Zhang, Hao, Minglei Shi, Lei Yang, and Yuancheng Guo. "A Semianalytical Solution for Passively Loaded Piles Adjacent to Surcharge Load." Advances in Civil Engineering 2020 (June 10, 2020): 1–19. http://dx.doi.org/10.1155/2020/2398389.
Testo completoAbstract (sommario):
Piles adjacent to a surcharge load commonly support not only active loads from superstructures but also the passive loads caused by soil lateral movement. To investigate the influence of passive load and the response along pile shafts of existing actively loaded piles, a load transfer model for analyzing the soil-pile interaction was developed based on plastic deformation theory and the triparameter soil model. An analytical solution for the deformation and internal force of such piles was proposed using the transfer matrix method, in which the transfer matrix coefficients for piles in free, plastic, and elastic zones were analytically obtained by considering the second-order axial force effect caused by lateral loading and soil yielding based on the triparameter soil model. The proposed methodology was validated by comparing its predictions with field measurements and previously published results. A good match between model predictions, field measurements, and previously published results implies that the proposed method can be used to evaluate the response of passive piles adjacent to a surcharge load. Parametric studies were also carried out to investigate the influence of surcharge pressure, soil resistance, and boundary conditions on the behavior of passively loaded piles adjacent to a surcharge load.
5
Liu, Jinglei, Xiuxin Li, Jinyuan Cao, Zhengchun Duan, Qingzhi Ye, and Guishuai Feng. "Geometric Parameter Effects on Bandgap Characteristics of Periodic Pile Barriers in Passive Vibration Isolation." Symmetry 16, no. 9 (2024): 1130. http://dx.doi.org/10.3390/sym16091130.
Testo completoAbstract (sommario):
To investigate the impact of the geometric parameters of periodic pile barriers on bandgap characteristics in passive vibration isolation, a two-dimensional, three-component unit cell was developed using the finite element method (FEM). This study analyzed the bandgap properties of periodic pile barriers and validated the effectiveness of the FEM through model testing. The FEM was then methodically applied to evaluate the effects of pipe pile thickness, periodic constant, arrangement pattern, and cross-sectional shape on the bandgap characteristics, culminating in the proposition of a novel H-shaped cross-section for the piles. The results demonstrated that the FEM-calculated bandgap frequency range, featuring steel piles arranged in a square pattern, closely aligned with the attenuation zone in the model tests. The lower band frequency (LBF) was primarily influenced by the pipe pile’s inner radius, while the upper band frequency (UBF) was predominantly affected by its outer radius. As the periodic constant increased, the LBF, UBF, and the width of band gap (WBG) all decreased. Conversely, changing the arrangement pattern from square to hexagonal led to increases in UBF and WBG, while the LBF diminished. Notably, the WBG of the H-section steel piles, possessing the same cross-sectional area, was 1.31 times greater than that of the steel pipe piles, indicating an enhanced vibration isolation performance. Additionally, the impact of transverse and vertical characteristic dimensions of the H-shaped pile on the band gap distribution was assessed, revealing that the transverse characteristic dimensions exerted a more significant influence than the vertical dimensions.
6
Wang, Qingshan, Zhaoran Xiao, Xianqiang Zhao, and Dakuo Feng. "The Effects and Vertical Bearing Capacity of Two Jacked Model Piles in Sand." Sustainability 14, no. 21 (2022): 14493. http://dx.doi.org/10.3390/su142114493.
Testo completoAbstract (sommario):
The effects and vertical bearing capacity of two jacked piles in sand are still not well understood, and the mechanism of the adjacent pile’s uplift caused by the jacking pile in a double pile system is especially unclear, but these facets are important to the stability of the jacked pile. In this paper, a series of tests is performed on jacked model piles in sand, where in the influences of the pile length and the driving pile’s speed on the effects and vertical bearing capacity of two jacked piles were studied. The results revealed that the effects and vertical bearing capacity of the two jacked piles were mainly in relation to pile length and influenced by the driving speed. The horizontal displacement of the top of the first jacking pile during the installation of the post-jacking pile was caused by the difference in the stress state of the first jacking pile between the side of the pile’s face and its back side, in which the uplift displacement of the first jacking pile was also involved. The radial stress of the pile increased nonlinearly with the depth under different pile lengths and gradually converged to the passive earth pressure. The ultimate capacity of the double pile is approximately twice that of a single pile, and the ratio of the ultimate capacity of a single pile to the final jacking pressure was approximately 1.04.
7
Guo, Wei Dong. "Response of rigid piles during passive dragging." International Journal for Numerical and Analytical Methods in Geomechanics 40, no. 14 (2016): 1936–67. http://dx.doi.org/10.1002/nag.2490.
Testo completo
8
Li, Tingting, Min Yang, and Xiaocen Chen. "A Simplified Analytical Method for the Deformation of Pile Foundations Induced by Adjacent Excavation in Soft Clay." Buildings 13, no. 8 (2023): 1919. http://dx.doi.org/10.3390/buildings13081919.
Testo completoAbstract (sommario):
The development of foundation excavations in congested urban areas inevitably induces stress release and soil movements, resulting in additional lateral deflections in adjacent pile foundations, commonly referred to as passive loading piles. Prior research on pile deflection resulting from nearby excavations primarily focused on single-pile behavior and paid little attention to the characteristics of pile groups. This paper presents a two-step approach to predicting the behavior of pile deformation resulting from nearby excavation. Firstly, Mindlin solution in combination with the double Gauss-Legendre formula is employed to calculate the additional lateral stress acting on the centerline of the passive pile resulting from nearby excavations. Secondly, the equation governing the deflection of the passive pile is determined using the Pasternak foundation model and solved using the finite difference method. On the basis of the Mindlin equation, shielding influence among piles is developed and applied to the analysis of a laterally loaded passive pile group. Last but not least, the accuracy of the presented approach is validated by comparing the results from two published centrifuge model tests with single piles and pile groups, and good agreements are obtained. Generally, the recommended two-step approach presents effective insight into the interaction between the excavation, soil, and pile, taking into account the influence of the shielding effect between piles. It can be applied as an alternative method for the conservation evaluation of the deformation tendency of pile foundation deformation in the pre-design of nearby excavations.
9
Xie, Yu, Shao-he Zhang, and De-quan Zhou. "Experimental Study of Mechanical Behavior of Passive Loaded Piles Adjacent to Piled Foundation." KSCE Journal of Civil Engineering 22, no. 10 (2018): 3818–26. http://dx.doi.org/10.1007/s12205-018-0565-x.
Testo completo
10
Karim, M. R., S. C. R. Lo, and C. T. Gnanendran. "Behaviour of piles subjected to passive loading due to embankment construction." Canadian Geotechnical Journal 51, no. 3 (2014): 303–10. http://dx.doi.org/10.1139/cgj-2012-0468.
Testo completoAbstract (sommario):
Behaviour of two embedded piles subjected to passive loading due to construction of an embankment was modelled in this paper. The piles were installed at the berm section of an embankment in a later stage of its construction. The investigation was carried out using a combination of two- and three-dimensional analyses. The analysis results were compared with the field-measured values and they agreed well.
Tesi sul tema "Passive Piles"
1
CAFERRI, LEONARDO. "Elasto-plastic models for the response of passive rigid piles." Doctoral thesis, Università Politecnica delle Marche, 2017. http://hdl.handle.net/11566/245380.
Testo completoAbstract (sommario):
Paratie di pali passivi sono state adottate con successo nel passato sia come intervento stabilizzante di fenomeni franosi attivi sia al fine di prevenire future instabilità, tanto da essere oggi una tecnica ampiamente accettata nella pratica ingegneristica.
Mentre i pali passivi sono generalmente impiegati con lo scopo di ridurre l’entità degli spostamenti del terreno, i criteri di progetto più comunemente utilizzati fanno riferimento alle sole condizioni limite del sistema palo-terreno, non considerando affatto fenomeni di interazione e per questo non risultando adeguati alla valutazione dell’effettivo campo di spostamenti sia dell’opera che del suolo adiacente.
Lo scopo della presente ricerca è quello di introdurre una metodologia di calcolo basata sugli spostamenti finalizzata all’analisi ed al progetto di pali passivi rigidi installati in diverse tipologie di terreno. In particolare, il metodo analizza il caso di un palo rigido immorsato in un terreno alla Winkler, sia libero che vincolato in testa. In particolare, il modello di terreno utilizzato permette l’implementazione di diverse stratigrafie di terreno e di considerarne lo spostamento come input di calcolo al fine di stimare la relativa deformazione del palo e le sollecitazioni di taglio e momento agenti sull’asta in funzione dello spostamento raggiunto dal terreno. Un codice di calcolo scritto in linguaggio FORTRAN è stato inoltre sviluppato al fine di svolgere il calcolo numerico.
Il metodo proposto risulta implementabile all’interno dei tradizionali metodi all’equilibrio limite o più in generale all’interno di metodi disaccoppiati. Sono inoltre state sviluppate delle abachi progettuali adimensionali per alcune semplici stratigrafie di terreno, nelle quali lo sforzo di taglio sulla superficie di scorrimento offerto dal palo è diagrammato, rispetto alla posizione della superficie stessa, in relazione al massimo momento flettente agente su di esso ed agli spostamenti del suolo e della testa del palo.<br>The use of piles to stabilise active landslides or to prevent future instabilities has been successfully applied in the past and is nowadays a widely accepted technique.
However, while the stabilising piles are usually designed with the aim of reducing the soil displacement rate, the design strategies commonly adopted in engineering practice apply to the ultimate state only, not taking into account any realistic interaction mechanism between pile and soil, and are not capable of predicting the effectiveness of the pile and soil displacement magnitude.
The goal of the present investigation is to propose a practical displacement-based numerical methodology for the analysis and design of passive rigid piles in different ground conditions. The developed method considers both a free-head and an unrotated-head rigid pile, embedded in a Winkler type soil and subjected to the sliding of a surrounding soil. The Winkler approach allows to consider a layered soil stratigraphy and to use the horizontal displacement of the surrounding soil as an input to evaluate the associated lateral deflection of the pile as well as the acting shear forces and bending moments in function of the external ground displacement. A FORTRAN computer program has been written to implement the numerical procedure.
The proposed method seems to be suitable for being implemented in traditional Limit Equilibrium Methods or more in general in any decoupled approach method. Moreover, non-dimensional design charts have been developed for simplified soil stratigraphies, in which the required shear force offered by the pile is plotted over the sliding surface depth, as a function of the pile head deflection, the maximum bending moment and the external soil displacement.
2
Ozturk, Sevki. "Distribution Of Bending Moments In Laterally Loaded Passive Pile Groups A Model Study." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/2/12610378/index.pdf.
Testo completoAbstract (sommario):
In this study, bending moment distributions developed in laterally loaded passive pile and passive pile groups in cohesionless soil were investigated in laboratory conditions through model pile experiments. Different from the active pile loading, the lateral load was given directly to the piles using a movable large direct shear box. In these experiments strain gauges fastened to the piles and a computer based data reading system were used. The strain values were measured at five levels on the piles. The behavior of a single pile and a pile group having five piles were investigated through strain measurements in order to observe bending moment distribution on the piles.
After evaluating the test results, the behavior of passive single pile was found to be similar to the results obtained in early studies. Negative bending moments were observed at the specified depths above the shear plane and positive bending moments were measured at the level of the shear plane and below the shear plane. Maximum bending moments were obtained at 0.7L (L: Length of Pile) for single piles and piles in the group. Above the shear plane, maximum bending moments within the pile
group were found to be developed on the piles nearest to the loading. On the shear plane maximum bending moments were developed on the piles farthest from the loading just like active piles. Below the shear plane, maximum bending moments were developed mainly on the piles nearest to the loading.
3
Silva, Sanchez Rosa Elvira. "Contribution au pronostic de durée de vie des systèmes piles à combustible PEMFC." Thesis, Besançon, 2015. http://www.theses.fr/2015BESA2005/document.
Testo completoAbstract (sommario):
Les travaux de cette thèse visent à apporter des éléments de solutions au problème de la durée de vie des systèmes pile à combustible (FCS – Fuel Cell System) de type à « membrane échangeuse de protons » (PEM – Proton Exchange Membrane) et se décline sur deux champs disciplinaires complémentaires :Une première approche vise à augmenter la durée de vie de celle-ci par la conception et la mise en œuvre d'une architecture de pronostic et de gestion de l'état de santé (PHM – Prognostics & Health Management). Les PEM-FCS, de par leur technologie, sont par essence des systèmes multi-physiques (électriques, fluidiques, électrochimiques, thermiques, mécaniques, etc.) et multi-échelles (de temps et d'espace) dont les comportements sont difficilement appréhendables. La nature non linéaire des phénomènes, le caractère réversible ou non des dégradations, et les interactions entre composants rendent effectivement difficile une étape de modélisation des défaillances. De plus, le manque d'homogénéité (actuel) dans le processus de fabrication rend difficile la caractérisation statistique de leur comportement. Le déploiement d'une solution PHM permettrait en effet d'anticiper et d'éviter les défaillances, d'évaluer l'état de santé, d'estimer le temps de vie résiduel du système, et finalement, d'envisager des actions de maîtrise (contrôle et/ou maintenance) pour assurer la continuité de fonctionnement. Une deuxième approche propose d'avoir recours à une hybridation passive de la PEMFC avec des super-condensateurs (UC – Ultra Capacitor) de façon à faire fonctionner la pile au plus proche de ses conditions opératoires optimales et ainsi, à minimiser l'impact du vieillissement. Les UCs apparaissent comme une source complémentaire à la PEMFC en raison de leur forte densité de puissance, de leur capacité de charge/décharge rapide, de leur réversibilité et de leur grande durée de vie. Si l'on prend l'exemple des véhicules à pile à combustible, l'association entre une PEMFC et des UCs peut être réalisée en utilisant un système hybride de type actif ou passif. Le comportement global du système dépend à la fois du choix de l'architecture et du positionnement de ces éléments en lien avec la charge électrique. Aujourd'hui, les recherches dans ce domaine se focalisent essentiellement sur la gestion d'énergie entre les sources et stockeurs embarqués ; et sur la définition et l'optimisation d'une interface électronique de puissance destinée à conditionner le flux d'énergie entre eux. Cependant, la présence de convertisseurs statiques augmente les sources de défaillances et pannes (défaillance des interrupteurs du convertisseur statique lui-même, impact des oscillations de courant haute fréquence sur le vieillissement de la pile), et augmente également les pertes énergétiques du système complet (même si le rendement du convertisseur statique est élevé, il dégrade néanmoins le bilan global)<br>This thesis work aims to provide solutions for the limited lifetime of Proton Exchange Membrane Fuel Cell Systems (PEM-FCS) based on two complementary disciplines:A first approach consists in increasing the lifetime of the PEM-FCS by designing and implementing a Prognostics & Health Management (PHM) architecture. The PEM-FCS are essentially multi-physical systems (electrical, fluid, electrochemical, thermal, mechanical, etc.) and multi-scale (time and space), thus its behaviors are hardly understandable. The nonlinear nature of phenomena, the reversibility or not of degradations and the interactions between components makes it quite difficult to have a failure modeling stage. Moreover, the lack of homogeneity (actual) in the manufacturing process makes it difficult for statistical characterization of their behavior. The deployment of a PHM solution would indeed anticipate and avoid failures, assess the state of health, estimate the Remaining Useful Lifetime (RUL) of the system and finally consider control actions (control and/or maintenance) to ensure operation continuity.A second approach proposes to use a passive hybridization of the PEMFC with Ultra Capacitors (UC) to operate the fuel cell closer to its optimum operating conditions and thereby minimize the impact of aging. The UC appear as an additional source to the PEMFC due to their high power density, their capacity to charge/discharge rapidly, their reversibility and their long life. If we take the example of fuel cell hybrid electrical vehicles, the association between a PEMFC and UC can be performed using a hybrid of active or passive type system. The overall behavior of the system depends on both, the choice of the architecture and the positioning of these elements in connection with the electric charge. Today, research in this area focuses mainly on energy management between the sources and embedded storage and the definition and optimization of a power electronic interface designated to adjust the flow of energy between them. However, the presence of power converters increases the source of faults and failures (failure of the switches of the power converter and the impact of high frequency current oscillations on the aging of the PEMFC), and also increases the energy losses of the entire system (even if the performance of the power converter is high, it nevertheless degrades the overall system)
4
Xing, Lanchang. "Passive slug mitigation by applying wavy pipes." Thesis, Cranfield University, 2011. http://dspace.lib.cranfield.ac.uk/handle/1826/9339.
Testo completoAbstract (sommario):
This work is to develop a passive slug mitigation technique based on a novel flow
conditioner, wavy pipe, through laboratory experiment and numerical simulation. The
wavy pipe has been applied to two types of slug flows: severe slugging in pipeline/riser
systems and hydrodynamic slug flow in horizontal pipelines.
The experiment of severe slugging mitigation was conducted on the 2” and 4”
pipeline/riser systems in the Three-Phase Test Facility in PSE (Process Systems
Engineering) Laboratory. The flow regimes in the pipeline/riser systems have been
classified into four categories, i.e. severe slugging, transitional severe slugging,
oscillation flow and continuous flow. Experimental results have revealed that: (1) the
severe slugging region in the flow regime map can be reduced by applying a wavy pipe;
(2) the wavy pipe is more effective when there is a pipe section of an appropriate length
between its outlet and the riser base; (3) a smaller severe slugging region can be
obtained with a longer wavy pipe (of more bends); (4) even if there is no flow regime
transition due to the application of a wavy pipe, the severity of the severe slugging and
oscillation flow can be reduced instead. The effects of the wavy pipe have been
summarised as reducing the slug length in the pipeline/riser system. For severe slugging
the wavy pipe works by accelerating the movement of the gas phase in the pipeline to
the riser base to initiate the bubble penetration stage; for the oscillation flow the wavy
pipe works by mixing the two phases of gas and liquid.
Two-dimensional CFD models of the 4” pipeline/riser and pipeline/wavy-pipe/riser
systems were developed in Fluent (Release 6.3.26) and the effects of the geometrical
parameters and location in the pipeline of the wavy pipe on severe slugging mitigation
were investigated numerically. The model predictions of the flow regime transition and
slug frequency in the pipeline/riser system agree with the experimental data well. It has
been concluded from the simulation that: (1) for a given pipeline/riser system
experiencing severe slugging, the severe slug length can be reduced further by
increasing the amplitude or length of the wavy pipe, respectively; however, the mean,
maximum and fluctuation amplitude of the drag and lift forces on the wavy pipe
increase with the increase of the wavy pipe amplitude and the mean, maximum and
fluctuation amplitude of the differential pressure across the wavy pipe increase with the
increase of the wavy pipe length; (2) the location of the wavy pipe relative to the riser
base has significant effects on the performance of wavy pipe; an optimum location of
the wavy pipe exists for a pipeline/riser system at given operating conditions.
The wavy pipe in a horizontal pipeline experiencing hydrodynamic slug flow was tested
on a two-phase test facility in PSE Laboratory. The wavy pipe has been found to be able
to mitigate the adverse impacts of hydrodynamic slug flow on the downstream facilities.
It has been concluded that the wavy pipe works as a mixer which is able to agitate the
gas/liquid two phases by its upward and downward limbs. More gas entrainment is
introduced into the slug body in the wavy pipe. The entrained gas distributes in the slug
body extensively due to the agitation effects of the wavy pipe. However, the flow tends
to recover after a certain distance downstream of the wavy pipe.
The horizontal wavy-pipe systems under hydrodynamic slug flow were modelled
applying STAR-OLGA coupling. The mixing effects of the wavy pipe on gas/liquid
two-phase flow identified in the experiment can be presented by the coupling model
reasonably well. The effects of the geometrical parameters of the wavy pipe, i.e.
amplitude and length, on hydrodynamic slug mitigation were examined. It has been
concluded that: (1) a wavy pipe of higher amplitude does not always introduce better
mixing effects because the longer upward limbs allow more liquid to accumulate thus
the liquid slugs tend to reform; a wavy pipe with amplitude of 1.8d is more desirable
than those of 1.1d and 2.5d (d the pipe diameter); (2) a wavy pipe of more bends (7
bends, L/d = 20.4, L the length of wavy pipe) is more favourable to mix the gas/liquid
two phases than the shorter ones (5 bends, L/d = 16.5; 3 bends, L/d = 11.1) because
more space and time can be provided for the two phases to interact with each other.
The forces acting on a single bend induced by hydrodynamic slug flow were
investigated using STAR-OLGA coupling. The predicted peak force on the bend agrees
with the experimental data in the literature. The force components on different areas of
the bend wall can be presented by the 3-D STAR model. The pressure-induced force
contour plots have shown the most vulnerable part on the bend wall prone to
mechanical damage.
5
Erentürk, Murat 1971. "The simulation of passive water hammer in pipes." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/38146.
Testo completo
6
Ramirez, Rivera Victor Manuel. "Energy management of lossy multi-port to fuel cell-based systems." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112087/document.
Testo completoAbstract (sommario):
Dans de nombreux réseaux, la régulation efficace du transfert d'énergie entre les sous-systèmes de production, de stockage et d'utilisation demeure un sujet difficile à traiter. Dans cette thèse on a proposent une nouvelle stratégie pour atteindre cet objectif, ainsi que sa mise en œuvre. Le dispositif est appelé routeur d'énergie dynamique (RED), parce que, contrairement à la pratique actuelle, l'asservissement de l'écoulement de puissance se fait sans s'appuyer sur des hypothèses stationnaire. Une hypothèse clé pour le bon fonctionnement du RED est que la dissipation du système est négligeable. Toutefois, en présence de pertes en ligne le RED initial n'est plus opérationnel, car il est base sur l'hypothèse clé de non dissipation des interconnections. Dans ce travail, un nouveau RED prenant en compte la présence de pertes est proposé. Des preuves de l'amélioration des performances sont présentées en simulation comme en expérimentation. Un complément de ce travail a été réalisée sur l'estimation des paramètres d'une pile à combustible du type Polymer Exchange Membrane (PEM) dans le but de concevoir un estimateur convergeant sur un grand domaine (convergence globale). Ce dernier utilise des principes d'immersion et d'invariance développés récemment dans la théorie des asservissements<br>Efficient regulation of the energy transfer between generating, storage and load subsystems is a topic of current practical interest. A new strategy to achieve this objective, together with its corresponding power electronics implementation, was recently proposed in this thesis work. The device is called dynamic energy router (DER) because, in contrast with current practice, the regulation of the direction and rate of change of the power flow is done without relying on steady–state considerations. A key assumption for the correct operation of the DER is that dissipation in the system is negligible. Unfortunately, in the presence of dissipation the original DER ceases to be operational. In this thesis a new DER that takes into account the presence of losses is proposed. Simulation and experimental evidence of the performance improvement with the new DER are presented. As a complement of this work a global convergent estimator of parameters of Polymer Exchange Membrane Fuel Cell (PEMFC) was designing by using the principles or “Immersion and Invariance” recently reported in control theory
7
Zhan, Weiguo. "Static pile passive aeration composting of poultry manure slurry." Thesis, University of Ottawa (Canada), 1993. http://hdl.handle.net/10393/6892.
Testo completoAbstract (sommario):
Static pile passive aeration composting (SPPAC) method is simple and economical. It can be applied to treat and stabilize animal wastes and reduce their adverse impact on the environment such as water, soil and air pollution. A study was carried out to investigate the effectiveness of SPPAC process for poultry manure slurry treatment under high initial MC conditions, using peat and straw as the bulking agents. Four treatments were examined, two of which were mixtures of poultry manure slurry and peat with initial MC of 73 and 80%. The other two treatments consisted of poultry manure slurry and chopped straw with initial MC of 72 and 76%, these two treatments had similar performances and results. Three replicate piles were monitored simultaneously for each treatment. The piles were trapezoidal and 3.35m$\sp3$ in volume. Two open-ended perforated pipes were laid at the bottom of each pile to provide aeration. A total of 316 thermocouples were installed in the compost piles to monitor temperature over a period of four months. Within 5 days thermophilic temperatures over 45$\sp\circ$C were attained in the compost piles confirming that passive aeration was effective and exothermic composting reactions started rapidly. Temperature distribution results illustrated that air diffusion and convection were the predominant aeration mechanisms. Cluster analysis of the temperature results provided a depiction of passive aeration, i.e., the ambient air was drawn into the compost through the lower parts of the piles to fill the void created by the up-moving heated air in the system. The temperature results also confirmed that the perforated pipes in the bottom of each pile increased aeration only in their vicinity. The compost with high moisture was successfully handled using the SPPAC method, no symptoms of anaerobic conditions were recorded. Mass balance results showed that nitrogen loss was lower in the compost of higher MC and lower pH, maximum 37% and 50% from the peat compost and the straw compost, respectively. Based on the guidelines of the Ontario Ministry of Environment, the final compost contained high levels of essential plant nutrients, the percent of total of nitrogen, phosphorus and potassium was greater than 4%, and the heavy metal levels were low. The peat is a better bulking agent than the straw. The performance among the three replicate piles of each treatment was highly stable and reproducible. The composting process took 30 to 90 days for the process to finish depending on the amount of poultry manure slurry in the different treatments.
8
Kartha, Satish Chandrashekhar. "Active, Passive and Active/Passive Control Techniques For Reduction of Vibrational Power Flow in Fluid Filled Pipes." Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/31156.
Testo completoAbstract (sommario):
The coupled nature of vibrational energy flow in fluid filled piping systems makes its control and subsequent reduction a difficult problem. This work experimentally explores the potential of different active, passive and active/passive control methodologies for control of vibrational power flow in fluid filled pipes. Circumferential modal decomposition and measurements of vibrational power carried by individual wave types were carried out experimentally. The importance of dominant structural bending waves and the need to eliminate them in order to obtain meaningful experimental results has been demonstrated. The effectiveness of the rubber isolator in reducing structural waves has been demonstrated. Improved performance of the quarter wavelength tube and Helmholtz resonator was obtained on implementation of the rubber isolator on the experimental rig. Active control experiments using the side-branch actuator and 1/3 piezoelectric composite yielded significant dB reductions revealing their potential for practical applications. A combined active/passive approach was also implemented as part of this work. This approach yielded promising results, which proved that combining advantages of both active and passive approaches was a feasible alternative.<br>Master of Science
9
Marsh, Robert Ashall. "Passive Earth pressures on a pile cap with a dense sand backfill /." Diss., CLICK HERE for online access, 2010. http://contentdm.lib.byu.edu/ETD/image/etd3356.pdf.
Testo completo
10
Marsh, Robert Ashall. "Passive Earth Pressures on a Pile Cap with a Dense Sand Backfill." BYU ScholarsArchive, 2009. https://scholarsarchive.byu.edu/etd/1958.
Testo completoAbstract (sommario):
Pile groups are often used to provide support for structures. Capping a pile group further adds to the system's resistance due to the passive earth pressure from surrounding backfill. While ultimate passive earth pressure under static loading conditions can be readily calculated using several different theories, the effects of cyclic and dynamic loading on the passive earth pressure response are less understood. Data derived from the full-scale testing of a pile cap system with a densely compacted sand backfill under static, cyclic, and dynamic loadings was analyzed with particular focus on soil pressures measured directly using pressure plates. Based on the testing and analyses, it was observed that under slow, cyclic loading, the backfill stiffness was relatively constant. Under faster, dynamic loading, the observed backfill stiffness decreased in a relatively linear fashion. During cyclic and dynamic loading, the pile cap gradually developed a residual offset from its initial position, accompanied by a reduction in backfill force. While the pile cap and backfill appeared to move integrally during static and cyclic loadings, during dynamic loading the backfill exhibited out-of-phase movement relative to the pile cap. Observed losses in backfill contact force were associated with both cyclic softening and dynamic out-of-phase effects. Force losses due to dynamic loading increased with increasing frequency (which corresponded to larger displacements). Losses due to dynamic loading were offset somewhat by increases in peak force due to damping. The increase in contact force due to damping was observed to be relatively proportional to increasing frequency. When quantifying passive earth forces with cyclic/dynamic losses without damping, the Mononobe-Okabe (M-O) equation with a 0.75 or 0.8 multiplier applied to the peak ground acceleration can be used to obtain a reasonable estimate of the force. When including increases in resistance due to damping, a 0.6 multiplier can similarly be used.
Libri sul tema "Passive Piles"
2
Stogo, Malcolm. Incredible ice cream: Making it your way with passion! : for professional ice cream artisans and home ice cream junkies. Ice Cream University Press, 2009.
Cerca il testo completoCapitoli di libri sul tema "Passive Piles"
1
Guo, Wei Dong. "Passive piles." In Advanced Design of Pile Foundations Under Lateral Loading. CRC Press, 2023. http://dx.doi.org/10.1201/9781003315230-6.
Testo completo
2
Hou, Xiaoqiang, Jierui Liu, Xinfei Wang, Zhongren Zhou, and Honglu Jia. "Research on Improvement Calculation Method of Design Thrust of Anti Slide Pile." In Lecture Notes in Civil Engineering. Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-1260-3_17.
Testo completoAbstract (sommario):
AbstractAt present, based on the transfer coefficient method, most of the anti-slide pile design thrusts are calculated by the overload method and the strength reserve method respectively. Many algorithms only consider the remaining sliding force behind the pile and the safety factor that meets the requirements of the design conditions. Generally, the safety factor is the safety factor of the sliding slope behind the pile after the anti slide pile is reinforced. For the entire landslide, there are two safety factors before and after the pile, which is not the design safety factor target value, and there is a big difference between the safety factor and the treatment goal required by the specification. Through the study of the pile-soil interaction of anti-slide piles, it is believed that in addition to the active residual sliding force transmitted by the blocks behind the pile, the anti-slide piles are simultaneously subjected to the passive residual anti-sliding force transmitted upwards by the blocks in front of the pile. The stress analysis shows that: Firstly, according to the different active and passive properties of anti-sliding force transmission and sliding force transmission, the mechanical model of anti-sliding force transmission is studied, and the calculation formula of anti-sliding force transmission coefficient is derived; Secondly, It is believed that the anti-slide pile provides horizontal thrust to the landslide, and two components of the sliding surface direction and the vertical sliding surface direction are generated. The balance equation is established and the overload method and the strength reserve method of anti-slide pile thrust calculation formula are derived; Thirdly, according to the principle of setting piles in the anti-slip section, the optimal location of anti-slide piles are proposed; Fourthly, after verification of cases, the safety factors before and after the piles calculated by the overload method are basically equal, and consistent with the design safety factors. Calculation result shows that the strength reserve method to calculate the safety factor before the pile is accurate and reliable, and the result of the safety factor behind the pile is relatively small.
3
Maus, Heiko, Harald Holz, Ansgar Bernardi, and Oleg Rostanin. "Leveraging Passive Paper Piles to Active Objects in Personal Knowledge Spaces." In Professional Knowledge Management. Springer Berlin Heidelberg, 2005. http://dx.doi.org/10.1007/11590019_5.
Testo completo
4
Lynch, Nancy J., and Robert S. Cherry. "Design of Passively Aerated Compost Piles: Vertical Air Velocities between the Pipes." In The Science of Composting. Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-009-1569-5_93.
Testo completo
5
Voigt, Immanuel, Axel Fickert, Hajo Wiemer, and Welf-Guntram Drossel. "Experimental Investigation of Passive Thermal Error Compensation Approach for Machine Tools." In Lecture Notes in Production Engineering. Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-34486-2_19.
Testo completoAbstract (sommario):
AbstractConventional approaches to counteract thermal issues in machine tools often require a significant amount of electrical energy input, such as in active cooling systems. An energy-efficient way for reducing thermal errors is to use passive components that redistribute heat introduced by feed drives and other internal heat sources. On the one hand, latent heat storage units can be integrated into the machine to enhance the thermal stability within the phase transition temperature range of the underlying phase change material. By using latent heat storage units, the impact of highly time-varying heat flows on the thermal displacement of the tool center point can be reduced. On the other hand, passive heat-transfer devices such as heat pipes allow for an increased heat exchange within the machine tool or between the machine tool and the environment. Heat pipes exhibit a very high effective thermal heat conductivity and can be used to transfer heat from machine-internal heat sources to additionally integrated heat sinks. A compensation system is presented combining latent heat storage units and heat pipe systems. To evaluate the effect of the corresponding components on thermally induced displacements, experimental investigations of the system within a machine tool are conducted. By means of temperature and displacement measurements it is demonstrated that the proposed compensation approach allows for partial compensation of the thermal error of the machine tool.
6
Chen, Zhimin, Mingyang Yi, Gengwang Zhang, and Zheng Zhang. "Stability Analysis of Surrounding Rock in Portal Section of Plateau Loose Rock Pile Tunnel Under Different Construction Methods." In Lecture Notes in Civil Engineering. Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-97-5814-2_26.
Testo completoAbstract (sommario):
AbstractRock pile is a rock block formed by weathering of bedrock, and its stability is lower than that of other rock and soil. Therefore, there are numerous difficulties in the construction of tunnels through rock pile. In this paper, TBM method, three step method and CD method are chosen as the basis of tunnel stability analysis, and the numerical model of surrounding rock excavation stability of tunnel passing through rock pile is established. In this paper, the tunnel excavation is simulated by numerical simulation software, and the stability analysis of tunnel under different construction methods is performed. Combined with the engineering background and calculation analysis, compared with the three construction methods, it is found that the CD method has the strongest comprehensive protection for tunnel construction and is a more suitable construction method for crossing the rock pile tunnel.
7
Jiang, Shu, Lianjun Ding, Huankai Li, et al. "Application of Passive Building Technology Based on Embedded Pipes in Walls." In Environmental Science and Engineering. Springer Nature Switzerland, 2024. http://dx.doi.org/10.1007/978-3-031-63901-2_36.
Testo completo
8
Rehman, Musabur, and S. M. Abbas. "Seismic Analysis of Pile Foundation Passing Through Liquefiable Soil." In Lecture Notes in Civil Engineering. Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-2545-2_45.
Testo completo
9
Hermans, William, and Simon Tan. "Investigating Passive Loading of an MSE Wall Bridge Abutment Supported on a Piled Foundation." In Lecture Notes in Civil Engineering. Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-97-8241-3_24.
Testo completo
10
Yau, Jong-Dar, Hsiao-Hui Hung, and Yeong-Bin Yang. "Investigation on soil-viaduct-pile vibrations induced by passing trains." In Wave propagation Moving load – Vibration Reduction. CRC Press, 2021. http://dx.doi.org/10.1201/9781003211372-11.
Testo completoAtti di convegni sul tema "Passive Piles"
1
Bavarian, Behzad, Akinbosede Oluwaseye, Lisa Reiner, and Jessica Meyer. "Migrating Corrosion Inhibitors to Protect Reinforced Concrete Structures." In CORROSION 2018. NACE International, 2018. https://doi.org/10.5006/c2018-11011.
Testo completoAbstract (sommario):
Abstract Most transportation infrastructure is built from steel and concrete. The steel may be in structural sections, such as girders, piles or rails, or embedded in concrete to form reinforced or prestressed concrete. Concrete provides excellent protection for embedded steel because Portland cement is very alkaline, forming a passive, protective layer on the steel surface. Concrete is also permeable, and even good-quality concrete can be penetrated by aggressive chemical ions that may initiate steel corrosion. Migrating corrosion inhibitors (MCIs), a blend of amine carboxylates and amino alcohols, show versatility as admixtures, surface treatments (coatings) and in rehabilitation programs. Examination of the embedded steel rebar after corrosion tests showed no corrosion attack for the MCI treated concrete samples, while non-treated concrete showed localized corrosion. X-ray photoelectron spectroscopy and depth profiling confirmed that the inhibitor had reached the rebar surface in about 150 days. The amine-rich compound on the rebar surface improved corrosion protection for the MCI treated steel rebar even in the presence of chloride ions and prevented red rust formation.
2
Akhoondan, Mersedeh, and Alberto A. Sagüés. "Unexpected Corrosion of Aluminized Steel Pipes in Limestone Backfill." In CORROSION 2013. NACE International, 2013. https://doi.org/10.5006/c2013-02650.
Testo completoAbstract (sommario):
Abstract Aluminized steel Type 2 (AST2), ASTM A929, has a ~50 um thick coating with outer and inner layers of commercially pure Al and Al-Fe intermetallic respectively. AST2 culvert and drainage pipes are required to have long service life (e.g. 75 yr) in natural soil and water environments; premature pipe failures incur heavy repair and replacement costs. Performance has been adequate in many service conditions, but unexpected early corrosion of AST2 pipes has been recently observed in some Florida inland locations. A recent event with loss of the coating and local penetration of the substrate, after only ~3 years of service was associated with the use of calcium carbonate-rich (limestone) backfill. Water in contact with limestone and allowed to equilibrate with CO2 in the atmosphere (open system) tends to develop a near neutral pH, compatible with a stable passive film on Al, so experiments were conducted to determine if the aggressive conditions took place otherwise. Simulated field fresh water conditions were created, where water in a limestone filled cell was constantly replenished at a slow rate (representing rainwater), while the pH and conductivity were monitored. Under these conditions, a high, steady state pH &gt; 9 developed that was aggressive to the aluminum passive film. The higher pH was ascribed to the dissolution of limestone in slowly flowing water that is not given enough time for equilibration with atmospheric CO2 (approaching a closed system). Electrochemical impedance measurements indicated the onset of severe corrosion early in the exposure, confirmed by metallographic and SEM observation of loss of coating in extracted AST2 specimens. The Al-Fe intermetallic was much less attacked. The corrosion rate decreased later as a thick corrosion product layer formed. Corrosion mechanisms are discussed. These findings merit consideration in updating specifications for the installation and use of backfill materials for aluminized steel culvert pipes.
3
Le Manchet, Sandra, Vincent Vignal, Djiby Ba, Olivier Heintz, and Frédéric Herbst. "Role of Alloying Elements and Ageing in the Pitting Corrosion Resistance of Duplex Stainless Steels." In CORROSION 2015. NACE International, 2015. https://doi.org/10.5006/c2015-05746.
Testo completoAbstract (sommario):
Abstract Duplex Stainless Steels (DSS) are highly important engineering materials due to their high corrosion resistance combined with high strength and moderate alloy cost (lower nickel and molybdenum content) compared to standard austenitic grades. They are widely used in various industrial sectors, such as oil & gas (pipes and storage tanks), desalination (evaporators and pumps) and pulp and paper (digesters and bleaching reactors) industries. In this paper, the influence of alloying elements on the passive film properties is first investigated after surface preparation and after ageing. The influence of the microstructure (Grain Orientation Spread (GOS) and Grain Surface Area (GSA)) on the corrosion resistance is then studied in NaCl solution by means of Critical Pitting Temperature (CPT) tests. Surface analysis was carried out in each phase of three DSS grades. No significant differences were observed in the properties of the passive films formed after etching. After ageing, there is a slight thickening of the passive films. The ratio Cr / Fe increases significantly for all grades whereas the ratio O2- / (OH- +H2O) increases only for grades with a pitting resistance equivalent number (PREN) greater than 25.5. N-H bonds were found at the outer interface whereas M-N bonds were located at the inner interface. Only N-H bonds were found for grade #3. This was attributed to the large amount of this element in grade #3. CPT measurements were carried out in ferrite grains of grade #1. It was shown that all the grains with a GOS value &lt; 1.3° remain passive (no pitting). For GOS &gt; 1.3°, metastable / stable pitting was systematically detected. It was found that the higher the GSA, the greater the CPT. Therefore, the GOS and the GSA seem to be two very important metallurgical parameters to predict pit initiation in DSS. The corrosion resistance will be increased by decreasing GOS or increasing GSA.
4
Garman, Faraj A. "Can Zinc Prevent Corrosion of Pre-Stressed Concrete Cylinder Pipes in High Resistivity Soils?" In CORROSION 2008. NACE International, 2008. https://doi.org/10.5006/c2008-08055.
Testo completoAbstract (sommario):
Abstract Zinc sacrificial anodes are not generally recommended to be used for the protection of steel in high resistivity soils (&gt;1500 Ω.cm) as the driving potential of the zinc will not be sufficient to provide the required current needed to drive the structure to soil potential to the protection criterion of -850 mV w.r.t. Cu/CuSO4. This criterion guarantees that the structure potential is shifted from the active region to the immunity region of the potential-pH diagram, where the corrosion process is to be completely halted. Generally, more than 300 mV of negative shift is required. Steel in concrete however, is in the passive region due to the alkaline environment provided by the concrete surrounding which allows the steel surface to develop a protective iron oxide film. Ingress of some species such as chloride ions leads to the destruction of this protective film and pitting of the steel reinforcement initiates. Potential of the steel in concrete is relatively less negative (generally &lt;-200mV) especially if the film damaging species have not reached the steel/concrete interface. The steel in this environment stays intact so long as the environment is not altered. Generally, one tenth of the CP current is sufficient to protect new reinforcing concrete structures where the passivity can be maintained. This means that immunity which requires a protection current of ten folds will not be required in this case. Zinc known for its numerous advantages over magnesium and aluminum in sacrificial cathodic protection systems, i.e. zinc anodes have relatively longer design life more efficient when delivering low current outputs, can then be used in high resistivity soils to protect steel in underground pre-stressed concrete cylinder pipes (PCCP). The high resistivity of the surrounding soil can initially have negative influence on the protective current density however, this detrimental effect does not last for long. This paper discusses some practical findings supporting this hypothesis.
5
Zhou, Jian, Xiao-liang Chen, Qing-you Zeng, and Biao Wu. "Model Tests and Numerical Simulations on Pile-Soil Interaction of Passive Piles." In GeoShanghai International Conference 2010. American Society of Civil Engineers, 2010. http://dx.doi.org/10.1061/41107(380)3.
Testo completo
6
Mujah, Donovan, Hemanta Hazarika, Naoto Watanabe, and Fauziah Ahmad. "Multirow Arrangement Of Laterally Loaded Passive Piles In Sand." In 18th Southeast Asian Geotechnical Conference (18SEAGC) & Inaugural AGSSEA Conference (1AGSSEA). Research Publishing Services, 2013. http://dx.doi.org/10.3850/978-981-07-4948-4_294.
Testo completo
7
Jiang, J., B. Qi, J. Zhou, and Q. Y. Zeng. "Model Test and PFC 2D Numerical Analysis on Soil Arching Effects Surrounding Passive Laterally Loaded Piles." In GeoShanghai International Conference 2010. American Society of Civil Engineers, 2010. http://dx.doi.org/10.1061/41101(374)36.
Testo completo
8
Carlisle, Derek. "From Passive Storage to Daily Waste Retrieval; Changing the Working Culture at Sellafield’s Pile Fuel Storage Pond." In ASME 2013 15th International Conference on Environmental Remediation and Radioactive Waste Management. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/icem2013-96207.
Testo completoAbstract (sommario):
The Pile Fuel Storage Pond (PFSP) was built in 1948/50 to treat materials from the Windscale Piles. Multiple operational regimes over the intervening 60 years have resulted in a complex inventory of spent nuclear fuels, solid and liquid intermediate level wastes. A coordinated programme of work, designed to retrieve and safely dispose of the pond contents, has been implemented to enable the decommissioning of the facility. The long period of passive storage operations which preceded the implementation of the programme meant that the operator was faced with a dual challenge of providing new technical capability and changing a working culture that was inappropriate for the dynamic environment required to successfully deliver the programme. It was recognised that the nature of the programme meant that implementing a standard manufacturing approach to operations would not be appropriate. In order to create a dynamic retrievals focussed working culture, the operator has vigorously embraced change programmes aimed at improving a number of working practices including encouraging innovation, managing integrated but flexible production schedules, and encouraging workface problem solving. The combined impact of beginning to resolve the technical challenges and focussing on the delivery culture has resulted in the facility making a step change towards becoming fully retrievals operations focussed.
9
Tart, Rupert G. "Pipeline Geohazards Unique to Northern Climates." In 2006 International Pipeline Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/ipc2006-10085.
Testo completoAbstract (sommario):
Pipelines in northern climates can be impacted by geohazards that are unique to cold regions. Some of these include frost heave, thaw settlement, solifluction, icings, glaciers, ice-rich slopes, and others. This paper will discuss most of these geohazards as they have been monitored, mitigated, and managed along the Trans Alaska Pipeline (TAPS) and other pipelines in Alaska and Russia. Early analyses of frost heave and thaw settlement of piles concluded that frost heave and thaw settlement would be controlled by installing passive heat removal devices (heat pipes). In permafrost areas heat pipes have generally worked well. In unfrozen terrain or discontinuous permafrost the heat pipes have not been able to maintain stability. Examples of each of these situations will be discussed. Steep rolling terrain makes up a significant part of the TAPS route. Some of the slopes are in permafrost and others are in thawed ground. For the past 15 years, surveillance and monitoring of some of the slopes along the pipeline route has documented the response of slopes in frozen ground. Warmer (that is near 0 degrees C) ice-rich slopes can creep. An example of this is documented on a slope instrumented with inclinometers and thermistors. Other slope movements related to pore pressure increases caused by active layer containment of unfrozen groundwater flows will be discussed. The impact of solifluction zones on pipeline construction and routing will be addressed as it has been managed along the TAPS. Other near surface slope movements that appear to be similar to solifluction have been observed along the pipeline right-of-way on the workpad. This paper will address an interrelationship of these observed slope behaviors. In doing this the interaction of slope seeps and the freeze front as it forms in fall and then recedes in spring and summer is compared to observations of engineered projects. Icings can be observed in several locations along TAPS. In some cases these can be related to slope movements. In other cases the icings have reached the aboveground and caused maintenance issues. TAPS was designed to avoid future surges of several large glaciers. In most years these glaciers have retreated and have not been a significant issue. A recent large earthquake caused a landslide on the largest glacier near TAPS and resulted in some review of the activity on that glacier. In 2002 a large earthquake centered near TAPS caused liquefaction in some areas, breakage of ice in lakes in some locations, and sand boils very close to the pipe. These observations will be related to the thinly frozen active layer over a deep talik during the earthquake.
10
Yekta, Kaveh, Ray Phung, Benjamin Stang, and Tyler Woitas. "Application of Real-Time Solid Measurement and Return Flow Rate During Coiled Tubing Milling Operations." In SPE/ICoTA Well Intervention Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/204451-ms.
Testo completoAbstract (sommario):
Abstract Among the many applications of Coiled Tubing (CT) services, milling plugs and wellbore sand cleanout are two of the major applications. The transport of solids to the surface, as well as monitoring the return rates, are two sources of information which can have a significant impact on the execution of these jobs. Traditionally the flowback crew communicates this information to the CT control cab upon request. However, by utilizing an acoustic monitor and ultrasonic flowmeter, it can reduce the dependence on flowback operators and provide real-time solid measurement and return flow rate. The acoustic monitor is a passive, non-intrusive device that is designed to measure the acoustic noise induced into the pipe wall as solids impact the inside wall of the pipe. The ultrasonic flowmeter is a clamp-on device that is designed with two transducers that serve as both a transmitter and receiver. In order to prove the concept, five stages of trials were planned and executed. In stage one, CT was rigged into a 150m vertical test well. The equipment included CT mast unit, CT pump, choke manifold, and acoustic monitoring device. Several debris piles from previous milling operations were introduced to the test well, and a CT cleanout was performed. The acoustic monitor system measured the amount of solid to surface, and the results were evaluated. Solids retrieved were then compared to the initial debris piles and correlated to the data received by the acoustic monitor. On the 2nd stage, the acoustic monitoring device was utilized in actual milling operation. The 3rd stage was a yard trial of ultrasonic flowmeter using a CT pump and data acquisition system to evaluate the working envelope of this device, followed by a field trial, in stage 4, utilizing the flowmeter in actual milling operations. The final stage of this trial was planned and executed in milling operations on a five wells pad, utilizing the combined applications of acoustic monitoring (solid measurement) and ultrasonic flowmeter (return rate) devices. All five stages contributed to proof of concept for the applications of solid measurement and return flow rate devices. These trials were successfully planned, executed, and evaluated. The acquired data throughout the five stages of these trials were utilized during and post job operations as lessons learned to optimize the process for future applications. The real-time measurement of solids and flow rate monitoring, independent of flowback operators, enables the CT operator to make informed decisions throughout milling and cleanout operations. The real-time streaming of solids to surface and return flow rate enables the operator and service company’s Engineering team to evaluate and optimize the execution of milling and sand cleanout operations.
Rapporti di organizzazioni sul tema "Passive Piles"
1
Ardalan, Hamed. Analysis of Landslides and Slopes Stabilized Using One Row of Piles. Deep Foundations Institute, 2013. http://dx.doi.org/10.37308/cpf-2012-land-1.
Testo completoAbstract (sommario):
The use of piles to stabilize active landslides or to prevent instability in currently stable slopes has become one of the most important innovative slope reinforcement techniques over the last few decades. Piles have been used successfully in many situations in order to stabilize slopes or to improve slope stability, and numerous methods have been developed for the analysis of piled slopes (Ito et al., 1981; Poulos, 1995; Chen and Poulos, 1997; Zeng and Liang, 2002; Won et al., 2005). The piles used in slope stabilization are usually subjected to lateral force through horizontal movements of the surrounding soil; hence they are considered to be passive piles. The interaction behavior between the piles and the soil is a complicated phenomenon due to its 3-dimensional nature and can be influenced by many factors, such as the characteristics of deformation and the strength parameters of both the pile and the soil. The interaction among piles installed in a slope is complex and depends on the pile and soil strength and stiffness properties, the length of the pile that is embedded in unstable (sliding) and stable soil layers, and the center-to-center pile spacing (S) in a row. Furthermore, the earth pressures applied to the piles are highly dependent upon the relative movement of the soil and the piles. The characterization of the problem of landslides and the use of piles to improve the stability of such slopes requires a better understanding of the integrated effect of laterally loaded pile behavior and the soil-pile-interaction above the sliding surface. Therefore, a representative model for the soil-pile interaction above the failure surface is required to reflect and describe the actual distribution of the mobilized soil driving force along that particular portion of the pile. In addition, the installation of a closely spaced pile row would create an interaction effect (group action) among adjacent piles not only below but also above the slip surface.
2
Rahai, Hamid, Assma Begum, Jeremy Bonifacio, and Ryan Moffit. Experimental Investigations of Wind Shear from Passing a Vehicle. Mineta Transportation Institute, 2024. https://doi.org/10.31979/mti.2024.2334.
Testo completoAbstract (sommario):
Wind energy can be harnessed for various commercial and transportation-related applications. This study assessed experimentally the potential of capturing wind energy from the passage of vehicles for electric power generation. Both wind tunnel experiments and field tests were performed. The wind tunnel experiments were performed in an open-circuit low-speed wind tunnel at a free-stream mean velocity of 23 m/s. Five PVC pipes placed adjacent to the wind-blowing domain were used to simulate the columns under a freeway overpass. A scaled Ahmad body (simplified car body model) was used as the vehicle. The spanwise distance between the Ahmad body and the tubes was 0.75 W where W is the width of the vehicle. The middle tube was used as a reference tube for circumferential and vertical pressure measurements. The streamwise locations of the vehicle were according to our previous transient numerical simulations as the vehicle approached and passed the columns at 0.1–0.5 sec. Results showed a significant potential of the transient wind generated from passing vehicles and identified optimized locations for harnessing this wind for electric power generation. Field tests were performed using a moving scaled Ahmad body. The vehicle speed was approximately 22 miles/hr (10 m/s.). Wind measurements were made up to 0.75 W adjacent to a vertical wall with static and total pressure taps. Results verified the corresponding wind tunnel results and showed a maximum transient wind of 10 m/s from the passing of the vehicle. These results were in agreement with our previous simulation results. The experiment results suggest great potential for harnessing the wind from vehicles to generate electric power, benefiting California's renewable energy goals.
3
Cruickshank, Garry, and Don Mardle. Wetback Research: Thermodynamic Flow Characteristics of Passive Thermosyphon Energy Transfer from Independent Heat Source to Remote Storage Using Both Direct and Indirect Systems. Unitec ePress, 2022. http://dx.doi.org/10.34074/rsrp.094.
Testo completoAbstract (sommario):
The method of heating water by means of a water jacket installed in the firebox of a solid-fuel burner, connected by pipes to a hot-water cylinder (HWC), was once commonplace in New Zealand, but has become less so in recent years. These systems, known as wetbacks, are covered by Building Code Clause G12, but considerable confusion has been caused by conflicting rules specified in the two main compliance documents, G12/AS1 and AS/NZS 3500.4 (hot water). In both compliance documents, wetback systems are defined as ‘uncontrolled heat sources’ with specific rules and limitations that stipulate how they are to be installed, and to keep them safe. However, other than common safety rules, each has entirely different ‘mandatory’ installation rules that affect the efficiency of the systems. They couldn’t both be right, but they could both be wrong. This is further confused by another standard, NZS 4603:1985, being mentioned in G12 as ‘another acceptable solution’ and differing from and contradicting both of the above. This standard is often quoted by manufacturers in their instructions. One driver of this research, from a regulatory view, was to determine which of the two main compliance documents was correct, if either.
4
Ricker, Richard E. DTRS56-04-X-0025 Pipeline Steel Corrosion Data from NBS Studies 1922-1940. Pipeline Research Council International, Inc. (PRCI), 2007. http://dx.doi.org/10.55274/r0011874.
Testo completoAbstract (sommario):
Between 1911 and 1984, the National Bureau of Standards (NBS) conducted a large number of corrosion studies that included the measurement of corrosion damage to samples exposed to real-world environments. One of these studies was an investigation conducted between 1922 and 1940 into the corrosion of bare steel and wrought iron pipes buried underground at 47 different sites representing different soil types across the United States. At the start of this study, very little was known about the corrosion of ferrous alloys underground. The objectives of this study were to determine (i) if coatings would be required to prevent corrosion, and (ii) if soil properties could be used to predict corrosion and determine when coatings would be required. While this study determined very quickly that coatings would be required for some soils, it found that the results were so divergent that even generalities based on this data must be drawn with care. The investigators concluded that so many diverse factors influence corrosion rates underground that planning of proper tests and interpretation of the results were matters of considerable difficulty and that quantitative interpretations or extrapolations could be done "only in approximate fashion" and attempted only in the "restricted area" of the tests until more complete information is available. Following the passage of the Pipeline Safety Improvement Act in 2002 and at the urging of the pipeline industry, the Office of Pipeline Safety of the U.S. Department of Transportation approached the National Institute of Standards and Technology (NBS became NIST in 1988) and requested that the data from this study be reexamined to determine if the information handling and analysis capabilities of modern computers and software could enable the extraction of more meaningful information from these data.
5
Krause, Thomas, Mehrdad Keshefi, Ross Underhill, and Lynann Clapham. PR652-203801-R02 Magnetic Object Model for Large Standoff Magnetometry Measurement. Pipeline Research Council International, Inc. (PRCI), 2021. http://dx.doi.org/10.55274/r0012151.
Testo completoAbstract (sommario):
Ferromagnetic pipeline steel may exhibit magnetization, even in the absence of applied magnetic fields, due to remnant fields or the presence of pipe wall stress. Remnant magnetization may be present from previous or existing exposure to a magnetic field, while pipe wall stress induced magnetization can result from line pressure, environmental stresses due to settling or geohazard conditions, and residual stresses due to nonuniform plastic deformation caused by manufacturing processes, installation or operating conditions. The local stress state of the pipeline may also be altered by corrosion or damage. The physical basis for magnetization in pipelines due to intrinsic and resident stresses is examined here using the magnetic object (MO) model. MOs are characterized as regions of relatively independent magnetic behaviour, typically about the size of a ferromagnetic steel grain, to which expressions for the magnetic energy of local domain structures can be applied. The lowest energy state for an MO is a flux-closed structure, but the presence of stress can modify the MO energy through inverse magnetostrictive effects on the domain structure and thereby, produce a state of magnetization. This magnetization may be altered by the introduction of additional stress sources including pressurization of the pipe, geological-environment effects, sources of magnetization that include the proximity of other ferromagnetic pipes, even those comprising sections of the same pipeline, and changes in the pipe structure that may be brought about by deformation, corrosion or cracking. This work shows that the fundamental building block of the MO, combined with considerations of overall changes in domain structure due to these factors, can be used to model the generation of magnetic fields measured outside of pipeline structures. This will have implications for understanding sources of pipeline magnetization that are passively measured above buried oil and gas pipelines with the objective of detecting anomalous conditions that may indicate compromised conditions for safe pipeline operation.
6
Wright, Louise, and Louise Crocker. PR-670-183826-R03 Extended Evaluation of LSM-Magnetostrictive Pipe Models. Pipeline Research Council International, Inc. (PRCI), 2021. http://dx.doi.org/10.55274/r0012097.
Testo completoAbstract (sommario):
Integrity assessment of pipelines is vital to ensure that oil and gas pipes have adequate strength to prevent leaks and ruptures. Regular inspections are conducted to confirm safe operation conditions of pipelines. The industry's principal method for assessing pipelines is in-line inspection (ILI), involving the passing of a device along the inside of a pipe to assess the condition of the pipeline. ILI devices can be fitted with a number of sensors allowing various measurement parameters to be obtained simultaneously. Not all pipelines are suited to ILI for reasons such as small diameter, obstructions within the pipe, or insufficient access to deploy or retrieve the ILI tools. These pipelines are sometimes referred to as 'difficult to inspect'. Alternative methods for examining pipeline condition are required with a range of technologies collectively known as Large Standoff Magnetometry (LSM) offering a promising solution for detection of pipe defects from a distance, reducing the need for excavation. LSM utilizes coupling between defects and changes in the magnetic properties of the pipeline material as a method for evaluation of pipe walls to identify the location of areas that require repair or further monitoring. Trials of existing commercial instruments by the pipeline industry have shown sufficient promise to investigate these technologies further. However, the vendors have supplied limited information on the underpinning physics of both the materials being tested and the instrument technology, meaning that further study is required in order to build confidence in the technique. The purpose of the project is to establish the ability of LSM to detect corrosion in API 5L pipe grades B to X70. The aim of the modelling work has been to use quantitative physics-based modelling techniques to predict the performance of LSM as a defect detection technique in situations that cannot easily be recreated in a laboratory environment, after validating the modelling approach by comparing measurements made in the laboratory to model results.
7
Finch, Graeme, and Stuart Harmon. PR-670-183826-R01 Assessment of Science Behind LSM for Pipeline Integrity. Pipeline Research Council International, Inc. (PRCI), 2020. http://dx.doi.org/10.55274/r0011803.
Testo completoAbstract (sommario):
Integrity assessment of pipelines is vital to ensure that oil and gas pipes have adequate strength to prevent leaks and ruptures. Regular inspections are conducted to confirm safe operation conditions of pipelines. The industry's principle method for assessing pipelines is in-line inspection (ILI), involving the passing of a device along the inside of a pipe to assess the condition of the pipeline. ILI devices can be fitted with a number of sensors allowing various measurement parameters to be obtained simultaneously. Not all pipelines are suited to ILI for reasons such as small diameter, obstructions within the pipe, or insufficient access to deploy or retrieve the ILI tools. These pipelines are sometimes referred to as 'difficult to inspect'. Alternative methods for examining pipeline condition are required, with a range of technologies collectively known as Large Standoff Magnetometry (LSM) offering a promising solution for detection of pipe defects from a distance, reducing the need for excavation. LSM utilises the coupling between defects and changes in the magnetic properties of the pipeline material as a method for evaluation of pipe walls to identify the location of areas that require repair or further monitoring. Trials of existing commercial instruments by the pipeline industry have shown sufficient promise to investigate the technologies further. However, vendors have supplied limited information on the underpinning physics of both the materials being tested and the instrument technology. The purpose of the project is to establish the ability of LSM to detect corrosion in API 5L pipe grades B to X70. The aim of Work Package 02 is to review the physics of the agreed pipeline defects and fluxgate type magnetic sensors. The properties of pipeline-specific soft magnetic materials are investigated to understand corrosion, how this alters the material properties and how this can affect the associated magnetic fields surrounding the material. The physics of fluxgate magnetometers and gradiometers are also reviewed to assess the ability of LSM to detect these two features.
8
Finch, Graeme, and Stuart Harmon. PR-670-183826-R02 Extended Evaluation of LSM - Magnetic Measurements of Corrosion Flaws. Pipeline Research Council International, Inc. (PRCI), 2021. http://dx.doi.org/10.55274/r0012189.
Testo completoAbstract (sommario):
Integrity assessment of pipelines is vital to ensure that oil and gas pipes have adequate strength to prevent leaks and ruptures. Regular inspections are conducted to confirm safe operation conditions of pipelines. The industry's principle method for assessing pipelines is in-line inspection (ILI), involving the passing of a device along the inside of a pipe to assess the condition of the pipeline. ILI devices can be fitted with a number of sensors allowing various measurement parameters to be obtained simultaneously. Not all pipelines are suited to ILI for reasons such as small diameter, obstructions within the pipe, or insufficient access to deploy or retrieve the ILI tools. These pipelines are sometimes referred to as 'difficult to inspect'. Alternative methods for examining pipeline condition are required with a range of technologies collectively known as Large Standoff Magnetometry (LSM) offering a promising solution for detection of pipe defects from a distance, reducing the need for excavation. LSM utilises coupling between defects and changes in the magnetic properties of the pipeline material as a method for evaluation of pipe walls to identify the location of areas that require repair or further monitoring. Trials of existing commercial instruments by the pipeline industry have shown sufficient promise to investigate these technologies further. However, the vendors have supplied limited information on the underpinning physics of both the materials being tested and the instrument technology, meaning that further study is required in order to build confidence in the technique. The purpose of the project is to establish the ability of LSM to detect corrosion in API 5L pipe grades B to X70. The aim of Work Package 04 is to measure the magnetic fields of a range of pipe samples containing manufactured corrosion flaws taking into account variables such as standoff distance, pressure, nearby ferromagnetic objects, position of the corrosion flaw around the pipe, track alignment, and orientation with respect to Earth's magnetic field. The results of these measurements will be used to validate computational models, which can be used to predict the magnetic response of a wider range of pipe geometries.