Academic literature on the topic 'Offshore in-situ measurements'
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Journal articles on the topic "Offshore in-situ measurements"
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Girleanu, Alina, Florin Onea, and Eugen Rusu. "Assessment of the Wind Energy Potential along the Romanian Coastal Zone." Inventions 6, no. 2 (2021): 41. http://dx.doi.org/10.3390/inventions6020041.
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The present work aims to provide a comprehensive picture of the wind energy potential that characterizes the Romanian coastal environment using in situ measurements and reanalysis of wind data (ERA5) that cover a 42–year time interval (1979–2020). A total of 16 reference points (both land and offshore) equally distributed along the Romanian sector are used to evaluate the local wind energy potential, targeting in this way several sites where a renewable wind project could be established. Compared to the in situ measurements (land points), the ERA5 dataset underestimates the wind speed by at least 11.57%, this value increasing as we approach the coastline. From the analysis of the spatial maps, it is likely that the wind speed steadily increases from onshore to offshore, with a sharp variation near the coastline being reported. Furthermore, the assessment of some state-of-the-art offshore wind turbines was conducted using 12 systems defined by rated capacity ranging from 2 to 10 MW. Some scenarios were proposed to identify sustainable offshore wind projects to be implemented in the Romanian coastal zone based on these results.
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Jangir, Pramod Kumar, Kevin C. Ewans, and Ian R. Young. "On the Functionality of Radar and Laser Ocean Wave Sensors." Journal of Marine Science and Engineering 10, no. 9 (2022): 1260. http://dx.doi.org/10.3390/jmse10091260.
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Ocean wave design criteria are required for the design of offshore platforms and floating systems, which are derived using in situ measurements. However, there is uncertainty regarding the performance of the instruments used for the in situ measurements. The main instruments used by the offshore industry are the Datawell Directional Waverider buoy and Rosemount WaveRadar, with Laser instruments also having been used for specific studies. Recent reports indicate measurements from these three instruments differ in the order of 10% but given the quite disparate nature of the measurements made by these instruments, it is far from clear what the source of this difference is. This paper investigates the wave measurement principles of Radar and Laser instruments using linear wave field simulations to better understand how the instruments perform. The Radar and Laser simulations include modeling electromagnetic signal beam reflections from water surfaces of an area equal to their footprint sizes, considering their beam characteristics and antenna pattern. The study confirms that the Radar underestimates spectral levels at frequencies above 0.5 Hz due to its significantly larger footprint at the water sea surface compared to the Laser (5.25 m vs. 0.15 m). The Laser performs well for almost the entire frequency range for all the cases considered.
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Remmers, Tiny, Fiona Cawkwell, Cian Desmond, Jimmy Murphy, and Eirini Politi. "The Potential of Advanced Scatterometer (ASCAT) 12.5 km Coastal Observations for Offshore Wind Farm Site Selection in Irish Waters." Energies 12, no. 2 (2019): 206. http://dx.doi.org/10.3390/en12020206.
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The offshore wind industry has seen unprecedented growth over the last few years. In line with this growth, there has been a push towards more exposed sites, farther from shore, in deeper water with consequent increased investor risk. There is therefore a growing need for accurate, reliable, met-ocean data to identify suitable sites, and from which to base preliminary design and investment decisions. This study investigates the potential of hyper-temporal satellite remote sensing Advanced Scatterometer (ASCAT) data in generating information necessary for the optimal site selection of offshore renewable energy infrastructure, and hence providing a cost-effective alternative to traditional techniques, such as in situ data from public or private entities and modelled data. Five years of the ASCAT 12.5 km wind product were validated against in situ weather buoys and showed a strong correlation with a Pearson coefficient of 0.95, when the in situ measurements were extrapolated with the log law. Temporal variations depicted by the ASCAT wind data followed the same inter-seasonal and intra-annual variations as the in situ measurements. A small diurnal bias of 0.12 m s−1 was observed between the descending swath (10:00 to 12:00) and the ascending swath (20:30 to 22:30), indicating that Ireland’s offshore wind speeds are slightly stronger in the daytime, especially in the nearshore areas. Seasonal maps showed that the highest spatial variability in offshore wind speeds are exhibited in winter and summer. The mean wind speed extrapolated at 80 m above sea level showed that Ireland’s mean offshore wind speeds at hub height ranged between 9.6 m s−1 and 12.3 m s−1. To best represent the offshore wind resource and its spatial distribution, an operational frequency map and a maximum yield frequency map were produced based on the ASCAT wind product in an offshore zone between 20 km and 200 km from the coast. The operational frequency indicates the percentage of time during which the observed local wind speed is between cut-in (3 m/s) and cut-out (25 m/s) for a standard turbine. The operational frequency map shows that the frequency of the wind speed within the cut-in and cut-off range of wind turbines was between 92.4% and 97.2%, while the maximum yield frequency map showed that between 40.6% and 59.5% of the wind speed frequency was included in the wind turbine rated power range. The results showed that the hyper-temporal ASCAT 12.5 km wind speed product (five consecutive years, two observations daily per satellite, two satellites) is representative of wind speeds measured by in situ measurements in Irish waters, and that its ability to depict temporal and spatial variability can assist in the decision-making process for offshore wind farm site selection in Ireland.
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Sultan, Nabil, and Sara Lafuerza. "In situ equilibrium pore-water pressures derived from partial piezoprobe dissipation tests in marine sediments." Canadian Geotechnical Journal 50, no. 12 (2013): 1294–305. http://dx.doi.org/10.1139/cgj-2013-0062.
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Excess pore-water pressure has a significant effect on submarine slope stability and sediment deformation, and therefore its in situ equilibrium measurement is crucial in carrying out accurate slope stability assessments and accurately deriving geotechnical design parameters. In situ equilibrium pore-water pressure is usually obtained from pore pressure decay during piezocone tests. However, submarine shelves and slopes are often characterized by the existence of low-permeability (fine-grained) sediments involving long dissipation tests that are an important issue for offshore operational costs. Consequently, short-term and (or) partial dissipation tests are usually performed and in situ equilibrium pore-water pressures are predicted from partial measurements. Using a modified cavity expansion approach, this paper aims to predict for four different sites the in situ equilibrium pore-water pressures. Comparisons between predicted and observed in situ equilibrium pore-water pressures allowed the development of a guide to evaluate the minimum time required to perform short-term dissipation tests for a given marine sediment. The main finding of this Note is that the second derivative of the pore pressure, u, versus the logarithm of time, t, ∂2u/∂ln(t)2 must be positive to calculate accurately the in situ equilibrium pore-water pressures from partial measurements.
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Mizuta, Darien Danielle, and Gary H. Wikfors. "Depth Selection and In Situ Validation for Offshore Mussel Aquaculture in Northeast United States Federal Waters." Journal of Marine Science and Engineering 7, no. 9 (2019): 293. http://dx.doi.org/10.3390/jmse7090293.
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As mariculture progresses offshore in the US Exclusive Economic Zone, technical and ecological challenges need to be overcome, such as the choice of suitable sites that favor the production of target species. The offshore culture of blue mussels, Mytilus edulis, is performed with submerged longlines and mussels need to withstand more motion than on coastal sites. Temperature affects the ability of the byssus to adhere to farming rope, while chlorophyll concentration provides an estimation of food availability. Together, these are important factors in predicting the suitability of offshore mussel farms. To identify suitable depth of submersion for mussel ropes in New England federal waters, historical oceanographic data of temperature and chlorophyll a from 2005 to 2012 were used. The results suggest that mussel ropes were submerged during summer to a minimum depth of 15 m in northern and a 20-m depth in southern areas of New England where temperature is at a species-optimum and phytoplankton biomass is abundant. For the site offshore Massachusetts, in situ biodeposition measurements validated predicted depth, confirming satisfactory mussel performance. Promising local areas have shallow thermoclines, such as offshore Long Island, Cape Ann and New Hampshire. Recommended depths can be adjusted to future temperature increases associated with climate change.
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Hudec, Bojan, Karla Ribičić, Sanja Martinez, and Ivana Šoić. "Quantitative Coating Quality Assessment on an Offshore Platform." Materials Performance 61, no. 1 (2022): 52–56. https://doi.org/10.5006/mp2022_61_1-52.
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Early signs of coating degradation were investigated by impedance measurements at 40 locations on a docked, jacketed offshore platform 1.5 and 2 years after full coating renewal. The platform coatings were evaluated in comparison to 38 reference samples with partial and complete coating systems that were aged at the shoreline for 1.5 years and subsequently tested in the laboratory in dry and wet states. The quantitative coating quality approach based on log Z measurements at 0.1 Hz and subsequent statistical analysis has provided means to quantitatively assess coating degradation in situ and identify a platform site with limited coating durability.
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Saviano, Simona, Anastasia Angela Biancardi, Florian Kokoszka, et al. "HF Radar Wind Direction: Multiannual Analysis Using Model and HF Network." Remote Sensing 15, no. 12 (2023): 2991. http://dx.doi.org/10.3390/rs15122991.
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HF radar systems have the potential to measure the wind direction, in addition to surface currents and wave fields. However, studies on HF radar for wind direction determination are rare in the scientific literature. Starting with the results presented in Saviano et al. (2021), we here expand on the reliability of the multiannual wind direction data retrieved over two periods, from May 2008 to December 2010 and from January to December 2012, by a network of three SeaSonde high-frequency (HF) radars operating in the Gulf of Naples (Central Tyrrhenian Sea, Western Mediterranean Sea). This study focuses on the measurements obtained by each antenna over three range cells along a coast–offshore transect, pointing to any potential geographically dependent measurement. The scarcity of offshore wind measurements requires the use of model-generated data for comparative purposes. The data here used are obtained from the Mediterranean Wind–Wave Model, which provides indications for both wave and wind parameters, and the ERA5@2km wind dataset obtained by dynamically downscaling ERA5 reanalysis. These data are first compared with in situ data and subsequently with HF-retrieved wind direction measurements. The analysis of the overall performance of the HF radar network in the Gulf of Naples confirms that the HF radar wind data show the best agreement when the wind speed exceeds a 5 m/s threshold, ensuring a sufficiently energetic surface wave field to be measured. The results obtained in the study suggest the necessity of wind measurements in offshore areas to validate the HF radar wind measurements and to improve the extraction algorithms. The present work opens up further investigations on the applications of wind data from SeaSonde HF radars as potential monitoring platforms, both in coastal and offshore areas.
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Zhang, Hong, Xiaolei Liu, Anduo Chen, Weijia Li, Yang Lu, and Xingsen Guo. "Design and Application of an In Situ Test Device for Rheological Characteristic Measurements of Liquefied Submarine Sediments." Journal of Marine Science and Engineering 9, no. 6 (2021): 639. http://dx.doi.org/10.3390/jmse9060639.
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Liquefied submarine sediments can easily lead to submarine landslides and turbidity currents, and cause serious damage to offshore engineering facilities. Understanding the rheological characteristics of liquefied sediments is critical for improving our knowledge of the prevention of submarine geo-hazards and the evolution of submarine topography. In this study, an in situ test device was developed to measure the rheological properties of liquefied sediments. The test principle is the shear column theory. The device was tested in the subaqueous Yellow River delta, and the test results indicated that liquefied sediments can be regarded as “non-Newtonian fluids with shear thinning characteristics”. Furthermore, a laboratory rheological test was conducted as a contrast experiment to qualitatively verify the accuracy of the in situ test data. Through the comparison of experiments, it was proved that the use of the in situ device in this paper is suitable and reliable for the measurement of the rheological characteristics of liquefied submarine sediments. Considering the fact that liquefaction may occur in deeper water (>5 m), a work pattern for the device in the offshore area is given. This novel device provides a new way to test the undrained shear strength of liquefied sediments in submarine engineering.
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Ji, Weidong, Rongfu Li, Wenfei Xue, et al. "Evaluation of ERA5 wind parameter with in-situ data offshore China." PLOS One 20, no. 5 (2025): e0317751. https://doi.org/10.1371/journal.pone.0317751.
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There are abundant wind energy resources along the coast of China. Understanding spatial-temporal characteristics of wind speed is significant in meteorology, coastal engineering design and maritime industries. Reliable wind products such as reanalysis data, coupled with accurate wind speed measurements, are essential for elucidating the primary characteristics of the wind field. In this study, we evaluated hourly 10 m and 100 m wind speed data from the fifth-generation ECMWF atmospheric reanalysis (ERA5) by comparing it with direct wind measurements obtained from 19 wind tower located across the coastal waters of China. The results are as follows: 1) the basic statistical characteristic between ERA5 reanalysis and observed wind speeds demonstrate good consistency. However, the ERA5 tends to underestimate wind speed, particularly at high speeds during extreme conditions. 2) Compare ERA5 data with observations from each station using a frequency distribution-based score method, hourly scores of most stations are between 0.8 to 0.9. It shows the higher simulation skill in the northern region than the southern due to the influence of high-frequency typhoon in the South China Sea. 3)Distribution function parameters, mean values, variability, and wind threshold frequencies were analyzed for this ensemble of observation, providing an overall description of wind characteristics. Generally speaking, there is no clear linear relationship between scores and the other variables. On longer time scales (6–24 hours), the score and correlation between ERA5 and observations further increased, while the centered root-mean-square error (CRMSE) and standard deviation decrease. 4) Hourly wind data with a regular spatial distribution in ERA5 reanalysis provides valuable information for further detailed research on meteorology or renewable energy perspectives, but some inherent shortcomings should be considered.
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Calore, Daniele, and Nicola Fraticelli. "State of the Art Offshore In Situ Monitoring of Microplastic." Microplastics 1, no. 4 (2022): 640–50. http://dx.doi.org/10.3390/microplastics1040044.
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Microplastics make up a significant amount of the overall quantity of plastic debris that is present in seawater. However, their detection and monitoring at sea is cost-inefficient and challenging; typically, it consists of water sampling with special manta nets, followed by long (i.e., weeks) laboratory analysis to obtain valid results. The analysis of the state-of-the-art technologies capable of monitoring/detecting microplastics in the sea (typically in coastal areas) presented in this paper shows that there are currently no specific tools to obtain quick measurements. The classic multiparametric probes are useless and the contribution of their relative chemical–physical parameters to determine the presence of microplastics in water is insignificant. The evolution in the last decade of hardware and software tools for capturing hologram images and related post-processing seems to be one of the most effective methods available currently for the rapid detection of microplastics in seawater. In particular, some results of monitoring campaigns carried out in the Adriatic Sea using this type of technology are reported. The acquired data are analyzed and discussed, highlighting their strengths and weaknesses, with indications of the possible methodologies that could be used to improve these systems.
Dissertations / Theses on the topic "Offshore in-situ measurements"
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Strömstedt, Erland. "Submerged Transmission in Wave Energy Converters : Full Scale In-Situ Experimental Measurements." Doctoral thesis, Uppsala universitet, Elektricitetslära, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-179740.
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Different wave power technologies are in development around the world in different stages of prototype testing. So far only a few devices have been deployed offshore at full scale for extended periods of time. Little data is published about how these different devices perform. This thesis presents results from experiments with the full-scale offshore wave energy converters at the Lysekil research site on the Swedish west coast. The theories, experiments, measurements, performance evaluations and developments of the submerged transmission in the direct driven permanent magnet linear generator are in focus. The reciprocating submerged transmission fulfills the purpose of transmitting the absorbed mechanical wave energy through the capsule wall into the generator, while preventing the seawater from entering the capsule and reducing the life time of the converter. A measuring system with seven laser triangulation sensors has been developed to measure small relative displacements between piston rod and seal housing in the submerged transmission with excellent accuracy for the purpose of evaluating both functional behavior and successive wear in-situ. A method for calculating relative tilt angles, azimuth angles, differential tilt angles, and successive wear in the submerged transmission has been developed. Additional sensors systems have been installed in the converter enabling correlation and a thorough investigation into the operating conditions of the transmission and the converter. The thesis presents unique results from the measurements. A data acquisition system transmits the signals from the converter on the seabed to an onshore measuring station. Results are presented in time-, frequency- and the time-frequency domain. The results have given important information for further development of the submerged transmission, which is important to the survivability of the system. The thesis describes the status of research, and is a step that may influence future designs of wave energy devices for reaching survivability and a cost-effective renewable energy system.<br><p>Published is a preprint version of the full text and should be combined by the errata.</p><br>The Lysekil Wave Power Project
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Marcille, Robin. "Learning-based forecasting of metocean variables : a path to maintenance operations optimization for offshore wind energy." Electronic Thesis or Diss., Ecole nationale supérieure Mines-Télécom Atlantique Bretagne Pays de la Loire, 2024. http://www.theses.fr/2024IMTA0416.
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Les opérations de maintenance de l’éolien en mer sont sensibles aux incertitudes des prévision météo-océaniques. Les modèles de prévision numérique sont limités par leur coût de calcul pour l’estimation des incertitudes, ce qui pousse au développement de méthodes basées sur l’apprentissage profond. L’importance des mesures in-situ en mer est mis en exergue par les résultats de cette thèse. Une méthode basée sur le clustering non supervisé de données de modèle numérique est proposée pour la définition d’un réseau de capteurs optimal pour la reconstruction de la ressource en vent. Des méthodes d’apprentissage profond sont proposées pour la prévision météo-océaniques probabiliste. Nous montrons leur intérêt pour assimiler un grand nombre de données d’entrée. Une hypothèse de postérieur Gaussien et une approche générative utilisant les flots normalisants sont comparées. Ceux-ci permettent de relâcher les hypothèses sur la distribution postérieure, maintenant une capacité d’échantillonnage et de calcul exact de la vraisemblance. Un cas d’étude réaliste est construit sur une zone représentative pour l’éolien en mer en France. Pour la prévision jointe du vent et des vagues, les propriétés non-Gaussiennes des flots normalisants se sont montrées bénéfiques à la calibration de la prévision. Un cadre d’évaluation représentatif des opérations en mer est proposé incluant la génération de scénarios et mesurant l’impact économique et le risque lié à la prise de décision. Nous montrons qu’il est crucial de prendre en compte le risque dans la sélection et l’évaluation des modèles de prévision<br>Offshore wind energy maintenance operations are highly sensitive to forecast uncertainty. Numerical weather prediction are limited by their computational cost for the uncertainty estimation and the update frequency, which is an argument for the development of data-driven methods. The importance of offshore measurements is highlighted by the results. A method for designing an optimal sensors network is proposed using unsupervised clustering. This method has been used by the French weather service to define future networks of floating LIDAR for offshore wind. Deep learning models for the joint probabilistic forecasting of metocean parameters are proposed. Their relevance for assimilating a large amount of input data is demonstrated. A Gaussian posterior and a generative approach using normalizing flows are compared. It is shown that the use of normalizing flows can relax any assumption on the shape of the forecast probability density while maintaining sampling and likelihood computation capabilities. A real case study dataset is built on a relevant area for offshore wind. The probabilistic models are adapted for joint wind and wave forecasting, for which the non-Gaussian properties of the normalizing flows is beneficial for forecast reliability. An evaluation framework dedicated to offshore operations is proposed, including the generation of probabilistic scenarios and the measure of decision-making economic impact. It is shown that the search for an economic optimum in the probabilistic decision-making leads to higher risk during operations, and this should be taken into account for forecast selection and evaluation
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Laya, Enrique J. "Système de surveillance pour la détection du dommage de fatigue cumulée dans les structures offshore en acier." Châtenay-Malabry, Ecole centrale de Paris, 1987. http://www.theses.fr/1987ECAP0048.
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Pour vérifier le comportement des liaisons tubulaires soudées, étude d'un système de mesure en temps réel des déformations sur la section nominale des tubes arrivant aux noeuds ; technologiquement le système est conçu à partir des matériels existants.
Books on the topic "Offshore in-situ measurements"
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Mardell, G. T., and J. Galloway. An Intercomparison of Dual H.F. Long Range Radar Data with in Situ Current Measurements (Offshore Technology Report). Stationery Office Books, 1989.
Find full textBook chapters on the topic "Offshore in-situ measurements"
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Silva, Armand J. "Comparison of in Situ and Ship-Board Vane Measurements on a Deep-Sea Clay." In Offshore Site Investigation. Springer Netherlands, 1985. http://dx.doi.org/10.1007/978-94-011-7358-2_14.
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Stuyts, Bruno, Wout Weijtjens, Carlos Sastra Jurado, and Christof Devriendt. "Improved Monopile-Soil Interaction Modeling through In Situ Monitoring." In State-of-the-Art of Mathematical Modelling, Dynamics, and Control of Wind Turbines Engineering [Working Title]. IntechOpen, 2024. http://dx.doi.org/10.5772/intechopen.1006730.
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The performance of offshore wind turbines is strongly influenced by the structural dynamics of the overall support structure. In situ measurements of the natural frequency of monopile-supported wind turbine structures have highlighted a mismatch between the as-designed and as-built natural frequencies of these structures. This design inaccuracy can be attributed to the lateral stiffness provided by the subsoil. Accurate characterization of the lateral support provided by the soil is further complicated by the non-linear and cyclic behavior of soil. Recent research on monopile soil-structure interaction has focused on onshore field testing and numerical modeling but there are limited investigations the in situ behavior of full-scale offshore wind turbines. In this contribution, in situ monitoring data from two Belgian offshore wind farms is used to investigate the applicability of the recently developed pile-soil interaction guidance to full-scale offshore structures and to suggest improvements where necessary. The research focuses on back-analysis of bending moments during quasi-static thrust loading. Strain measurements along the length axis of the monopile allow direct measurement of the bending moment absorption below the mudline. The monitoring data reveals an important contribution of the scour protection system installed around the foundation, which can be accounted for in the pile-soil interaction calculations.
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Wu, Caihong, Chunxi Zhuang, and Xu Zhang. "Application of Dipole Acoustic Logging in Wave Velocity Testing in Soft Formation in Offshore Areas." In Advances in Transdisciplinary Engineering. IOS Press, 2024. https://doi.org/10.3233/atde241157.
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Wave velocity measurement is one of the frequently-used and indispensable in-situ test in offshore wind power engineering investigation. The test results can be used to calculate the dynamic parameters of the soil and to evaluate the engineering geological characteristics of the site. Influenced by the severe environment in the ocean, the traditional continental wave velocity measurement is greatly restricted, and it is necessary to carry out a comparative study on the in-situ wave velocity test method in offshore. Relying on Jiangsu Dafeng offshore wind power project, through the field application of dipole sonic logging, as well as bending-extension element indoor test, it is found that dipole sonic logging has the significant advantages of fewer influencing factors, higher efficiency, and more accurate and reliable quality of the results compared with PS logging, and it can be used as the main method of wave velocity testing for the offshore engineering.
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Coop M.R., Fahey M., and Consoli N.C. "The interpretation of conventional and non-conventional laboratory tests for challenging geotechnical problems." In Deformation Characteristics of Geomaterials. IOS Press, 2011. https://doi.org/10.3233/978-1-60750-822-9-84.
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This overview paper discusses the use of laboratory testing in conjunction with in situ determination of reference parameters as a step forward to have consistent analyses of the behaviour of geotechnical constructions. In the first part of the paper, the key role of those reference properties, such as the elastic stiffness values obtained in field conditions at repose stress state, is highlighted. By comparing these values with those determined in laboratory reconditioned samples, their &ldquo;undisturbed&rdquo; conditions are evaluated and the reliability of advanced laboratory techniques can thereby be assured. The use of seismic wave velocity (Vs) measurements in the field and the laboratory is discussed, and examples are given. Particular emphasis is placed on using the ratio of Vs,field/Vs,labfor the correction of constitutive stress-strain laws &ndash; i.e. the stiffness &ldquo;decay&rdquo; (G&ndash;&gamma;) curves determined in laboratory tests. This is becoming a more feasible approach because of the increasing prevalence of laboratory Vsmeasurement using &ldquo;bender elements&rdquo; in laboratory tests at different stages of testing and under diverse stress paths, coupled with the increasing use of seismic cone penetration tests (SCPT) for determination of Vs,field. A second subject that is discussed in some detail is the advantage of looking at soil liquefaction as an elasto-plastic mechanical behaviour that is well modelled by critical states concepts, while recognising that it takes places in a wide range of materials and conditions. These issues are outlined in this section, as the critical state framework has now been extended to other materials apart from sands. This approach integrates the knowledge of influence of the micro-mechanics of particles and their contacts on the observed behaviour, and takes account of the effects of continued particle breakage and change in uniformity. The objectives of performance-based design are presented in the light of laboratory and field tests that may be able to identify the triggering risk of both cyclic and static liquefaction and how those tests can be performed and their results interpreted to predict these phenomena, under a global mechanical modelling approach. The third part of the paper describes some special geotechnical testing procedures (equipment and methods of interpretation of test results) that are commonly used in advanced laboratories working for the offshore industry. Being scarcely known and used in current laboratories, even with advanced equipment, these techniques have a great potential in answering to the challenging problems involved in this area of activity, but is it also demonstrated that they can give very useful information in other geotechnical problems. The final section describes a new dosage methodology, based on rational criteria, for cement-soil mixtures, where porosity/cement ratio plays a fundamental role in the assessment of the target mechanical properties of artificially cemented soils, which are used increasingly in many geotechnical engineering solutions.
Conference papers on the topic "Offshore in-situ measurements"
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Strømmen, R. D., H. Osvoll, and W. Keim. "Computermodeling and In-Situ Current Density Measurements Prove a Need for Revision of Offshore CP Design Criteria." In CORROSION 1986. NACE International, 1986. https://doi.org/10.5006/c1986-86297.
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Abstract During recent years there has been a trend towards development and application of current density monitoring equipment in combination with potential measurements on the North Sea structures. In the same period there has also been a strong development of numerical methods for computer modeling of offshore cathodic protection systems. This paper presents results obtained with such modern techniques in monitoring of North Sea platforms. In particular the results demonstrates that the current density requirements for CP in the North Sea are considerably lower than normally anticipated. It is furthermore shown that the sacrificial anode weight may be reduced by introducing changes in the design rules, taking these findings into account.
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Wang, Y., J. A. Wharton, J. Downes, and R. A. Shenoi. "Marine Structural Integrity Subject to Mechano-electrochemical Induced Corrosion." In CORROSION 2017. NACE International, 2017. https://doi.org/10.5006/c2017-09656.
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Abstract Carbon steel marine platforms, including ships and offshore structures, are at high risk of corrosion due to the combination of aggressive seawater environment, corrosive cargoes and constantly changing loading conditions. In particular, the combined influence of mechanical and electrochemical effects (which is often termed mechano-electrochemistry) has gained increasing attention over the last decade. Although various experiments, along with theoretical/empirical expressions, have been proposed to establish the relationship between stress/strain and the corrosion behavior, there are few in situ measurements of corrosion and the mechanical properties. Moreover, such corrosion mechanisms have not been incorporated for large scale ship or offshore structural members. This work has developed an experimental protocol including in situ potentiostat and quasi-static tensile tests to provide an improved understanding of the corrosion behavior of UNS G10210 steel at different stress levels. A novel local-global finite element method has been proposed to model a steel plate at a ship compartment scale under uniaxial quasi-static tensile/compressive loading. The stress distributions together with the experimental measurements were utilized to simulate a local mechano-electrochemical corrosion process and predict the stress-induced corrosion rate change. The modeling results demonstrate a more realistic approach to estimate marine structural integrity considering stress-induced localized corrosion.
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Asher, J., T. W. Conlon, B. C. Tofield, S. Sugden, and P. F. Lawrence. "Experience of Plant Corrosion Monitoring by Thin Layer Activation." In CORROSION 1986. NACE International, 1986. https://doi.org/10.5006/c1986-86131.
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Abstract A new technique for plant corrosion monitoring, Thin Layer Activation (TLA), is described. Specific trials have been carried out to develop TLA for corrosion monitoring (CM) in the offshore oil industry. Two development trials are described. In the first, standard weight-loss coupons, augmented by TLA, were installed in production wellheads and retrieved for laboratory analysis of corrosion by activity measurements; the second was a trial, on a water treatment plant, of a TLA corrosion monitor instrument system where in situ results are compared with other CM instruments operating on the same plant.
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Ballard, Jean-Christophe, and Richard Jewell. "Observations of pipe-soil response from in-situ measurements." In Offshore Technology Conference. Offshore Technology Conference, 2013. http://dx.doi.org/10.4043/24154-ms.
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Jing, Xu-Dong, Alisdair Gillespie, and B. M. Trewin. "Resistivity Index From Non-Equilibrium Measurements Using Detailed In-Situ Saturation Monitoring." In Offshore Europe. Society of Petroleum Engineers, 1993. http://dx.doi.org/10.2118/26798-ms.
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Naylor, P., N. C. Sargent, A. P. Tilsed, and M. D. Frorup. "Oil Relative Permeability for Gravity Drainage Based on In-Situ Saturation Measurements." In Offshore Europe. Society of Petroleum Engineers, 1991. http://dx.doi.org/10.2118/23101-ms.
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Sharma, Neha, Jill S. Storie, Kelsey M. Obenour, Michael J. Leber, and Ashwanth Srinivasan. "Loop Current Hyperactivity: Analysis of In Situ Measurements in the Gulf of Mexico." In Offshore Technology Conference. Offshore Technology Conference, 2016. http://dx.doi.org/10.4043/27229-ms.
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Taboada, Victor Manuel, Shuang Cindy Cao, Diego Cruz roque, and Procoro Barrera Nabor. "Assessing Small-Strain Shear Modulus Based On In Situ Seismic Measurements in Bay of Campeche Sand." In Offshore Technology Conference. OTC, 2023. http://dx.doi.org/10.4043/32583-ms.
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Abstract A database with in situ measurements of shear wave velocity (VS), cone tip resistance (qc), and basic soil properties of sand has been established from fifteen offshore geotechnical investigations performed in the Bay of Campeche. VS values were obtained from P-S logging. The database was tailored to develop empirical correlations for small-strain shear modulus (Gmax) based on qc (or relative density), void ratio, and effective stress. Three empirical correlations were developed to determine Gmax based on: 1) void ratio, effective vertical stress, and coefficient of lateral earth pressure at rest; 2) effective vertical stress and relative density determined from CPT data; and 3) effective vertical stress and cone tip resistance. To evaluate the accuracy of the correlations, a comparison was made between VS computed from the three empirical correlations and in situ VS measurements at an independent site. The predictions of VS fall in a rather narrow band, 15 % lower and higher than the in situ VS measurement, which supports the conclusion that these equations provide a useful approach to estimating VS or Gmax for use in ground response analyses or offshore wind farm foundation design at sites where time constraints and finite resources prevent the feasibility of making in situ VS measurements.
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Tjelta, T. I., A. W. W. Tieges, F. P. Smits, J. M. Geise, and T. A. Lunne. "In-Situ Density Measurements by Nuclear Backscatter for an Offshore Soil Investigation." In Offshore Technology Conference. Offshore Technology Conference, 1985. http://dx.doi.org/10.4043/4917-ms.
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Teufel, L. W. "In Situ Stress Measurements In Inclined Holes In The North Sea: Application To Water Flooding And Enhanced Oil Recovery." In Offshore Europe. Society of Petroleum Engineers, 1985. http://dx.doi.org/10.2118/13986-ms.
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