Volume 9: Offshore Geotechnics最新文献

On the Erasing of the Cyclic Preloading by Monotonic Deformations in Granular Soils 颗粒土单调变形对循环预压的消除研究

Volume 9: Offshore Geotechnics Pub Date : 2022-06-05 DOI: 10.1115/omae2022-79696

Andreas Wappler, L. Knittel, A. Niemunis, H. Stutz

{"title":"On the Erasing of the Cyclic Preloading by Monotonic Deformations in Granular Soils","authors":"Andreas Wappler, L. Knittel, A. Niemunis, H. Stutz","doi":"10.1115/omae2022-79696","DOIUrl":"https://doi.org/10.1115/omae2022-79696","url":null,"abstract":"\u0000 For the design and construction of Offshore Wind Energy Turbines (OWT), it is essential to predict deformations in the subsoil. Wind and waves cause a high-cycle loading on these structures. To ensure their servicability, reliable soil models for predicitions of cumulative displacement over the expected OWT lifetime are needed. In this work, the explicit constitutive High-Cycle Accumulation Model (HCA-Model) by Niemunis et al. [1] has been modified to account for the influence of large monotonic strains on the rate of subsequent cyclic accumulation. In this research project, 21 drained cyclic triaxial tests on saturated, cylindrical Karlsruhe fine sand samples were performed. The packages of cycles were applied on the specimens one after another. Between the packages, the average stress state was monotonically changed. To examine the reduction of the so called cyclic preloading, the tests were analysed regarding the accumulated strain throughout the packages of cycles in each test and the monotonic strain resulting from the change of the average stress state between the packages. In addition, finite-element calculations on an exemplary shallow foundation of an OWT were performed. Two packages of cycles with modification of the cyclic preloading were studied. The reduction of the cyclic preloading was evident.","PeriodicalId":427776,"journal":{"name":"Volume 9: Offshore Geotechnics","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132883173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A Numerical Macro Model to Simulate the Whole Life Response of Anchors for Floating Offshore Renewable Energy Systems 海上浮式可再生能源系统锚杆全寿命响应的宏观数值模拟

Volume 9: Offshore Geotechnics Pub Date : 2022-06-05 DOI: 10.1115/omae2022-81101

K. Kwa, N. Sivasithamparam, A. Deeks, D. White

{"title":"A Numerical Macro Model to Simulate the Whole Life Response of Anchors for Floating Offshore Renewable Energy Systems","authors":"K. Kwa, N. Sivasithamparam, A. Deeks, D. White","doi":"10.1115/omae2022-81101","DOIUrl":"https://doi.org/10.1115/omae2022-81101","url":null,"abstract":"\u0000 The offshore renewable energy (ORE) industry is developing new solutions to enable floating facilities that can operate further from shore where more ocean space is available and stronger wind resources can be harnessed. Future ORE facilities will involve arrays of devices that connect and will transmit loads to the seafloor via mooring and anchoring systems. Therefore, it is essential to have a reliable estimation of the capacity that the anchoring system can provide for the variety of loads that are transmitted via the mooring lines.\u0000 This paper provides a model for soft soils (i.e. soft clays, loose-medium silts and sand), where the capacity can evolve with time due to the sustained loads and variable components of the cyclic loads, which vary due to environmental conditions and the characteristics of the floating system. The model is referred to as a ‘macro-model’, meaning that the response of all soil elements around the anchor are defined by a representative value of strength and other properties at a single node. The model captures ‘hidden’ anchor capacity enhancements from (i) ‘whole-life’ changing soil strength, (ii) viscous effects on soil strength and (iii) added soil mass effects, which are usually absent in geotechnical foundation design.\u0000 It is shown that these effects can be efficiently modelled and integrated into existing numerical analysis packages to provide a new basis for assessing through-life changes in geotechnical anchor capacity. This enables a better understanding of the fully coupled soil-anchoring-mooring behaviour of floating infrastructure over its operational lifetime.","PeriodicalId":427776,"journal":{"name":"Volume 9: Offshore Geotechnics","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123060706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Numerical Modelling of Residual Liquefaction in the Subsoil Under a Vibrating Plate 振动板作用下地基残余液化的数值模拟

Volume 9: Offshore Geotechnics Pub Date : 2022-06-05 DOI: 10.1115/omae2022-79025

Ranjith khumar Shanmugasundaram, H. Rusche, C. Windt, V. Kirca, B. Sumer, N. Goseberg

{"title":"Numerical Modelling of Residual Liquefaction in the Subsoil Under a Vibrating Plate","authors":"Ranjith khumar Shanmugasundaram, H. Rusche, C. Windt, V. Kirca, B. Sumer, N. Goseberg","doi":"10.1115/omae2022-79025","DOIUrl":"https://doi.org/10.1115/omae2022-79025","url":null,"abstract":"\u0000 Seabed liquefaction is the phenomenon by which the seabed soil loses its strength and stiffness, due to applied stress, and behaves like a non-Newtonian fluid. Seabed liquefaction can lead to severe failure of marine structures, such as buried pipelines or coastal breakwaters. Numerical modelling of liquefaction can provide valuable insights into the prevailing wave-structure-soil interaction. However, the holistic modelling of seabed liquefaction, including the transition from solid to liquid and back to solid soil, is challenging, due to the prevailing hydrogeotechnical processes. As a step towards the development of such a holistic numerical model of seabed liquefaction, this paper considers the modelling of the soil under a rocking plate as an idealised representation of a caisson breakwater as presented in [1]. The numerical model has recently been presented in [2] and includes equations for the accumulation of pore pressure and a criterion to distinguish between the liquefied and non-liquefied regions. The numerical results are compared to the experimental results taken from [1]. Different numerical model setups are presented to overcome modelling challenges due to occurring punching shear failure.","PeriodicalId":427776,"journal":{"name":"Volume 9: Offshore Geotechnics","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124586949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Numerical Investigation of Ship Anchor Penetration in Cohesive Baltic Sea Soil 波罗的海粘性土中船舶锚穿深的数值研究

Volume 9: Offshore Geotechnics Pub Date : 2022-06-05 DOI: 10.1115/omae2022-80822

D. A. Dao, J. Grabe

引用次数: 0

Importance of Numerical Analyses to Inform Laboratory Testing for Offshore Slope Stability Assessment 数值分析对海上边坡稳定性评估实验室测试的重要性

Volume 9: Offshore Geotechnics Pub Date : 2022-06-05 DOI: 10.1115/omae2022-80164

B. Carlton, H. Suroor, Y. Choi, R. Hansen, F. Nadim, M. Saqab, A. Kaynia

{"title":"Importance of Numerical Analyses to Inform Laboratory Testing for Offshore Slope Stability Assessment","authors":"B. Carlton, H. Suroor, Y. Choi, R. Hansen, F. Nadim, M. Saqab, A. Kaynia","doi":"10.1115/omae2022-80164","DOIUrl":"https://doi.org/10.1115/omae2022-80164","url":null,"abstract":"\u0000 An offshore pipeline will cross a series of steep rocky escarpments. Borehole samples show that there are thin layers of uncemented sand deposits at the head and middle of the largest escarpment. Bathymetry data also show evidence of past landslide activity, and the escarpments lie in a moderately seismic area. As a result, advanced, site-specific slope stability analyses were carried out to assess the failure potential of the slope in the event of project-specific design earthquakes. Analyses included deterministic and probabilistic static and pseudo-static slope stability analyses as well as dynamic time domain analyses. The initial results showed unacceptably low factors of safety against slope instability in the event of an earthquake based on empirically derived soil parameters. Consequently, additional advanced laboratory testing was performed to characterize better the dynamic properties and strength of the critical soil layer, and the pseudo-static and time domain analyses were repeated. Using the updated soil properties, the factor of safety and expected displacements during seismic shaking were reduced to satisfactory levels. The case history presented in this paper provides a clear example of the benefit of performing additional advanced laboratory testing to reduce uncertainty after numerical analyses have identified critical soil layers.","PeriodicalId":427776,"journal":{"name":"Volume 9: Offshore Geotechnics","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132882359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Experimental and Numerical Studies on the Axial Bearing Behaviour of a Pile Due to Relevant Foundation Fill Material on the Coastal Tidal Flat 滨海潮滩上相应地基填筑材料对桩轴向承载性能的试验与数值研究

Volume 9: Offshore Geotechnics Pub Date : 2022-06-05 DOI: 10.1115/omae2022-79769

Juntian Yao, K. Shen, Kuan-jun Wang, Jian Yu, Maosong Huang

引用次数: 0

Indentation Test Implementation for Rock Strength Correlation by Experimental Method and Simulation Using Distinct Element Method 岩石强度相关性压痕试验的实验方法与离散元法模拟

Volume 9: Offshore Geotechnics Pub Date : 2022-06-05 DOI: 10.1115/omae2022-79227

Prajit Premraj, Zijian Li, A. Abugharara, S. Butt

引用次数: 0

On the Influence of the Soil Stratigraphy on the Monopile Deflection Investigated With FEM in a PISA Framework 在PISA框架下用有限元法研究土壤地层对单桩挠度的影响

Volume 9: Offshore Geotechnics Pub Date : 2022-06-05 DOI: 10.1115/omae2022-79329

M. Kanitz, Carlos Molina Mesa, Luís Berenguer Todo Bom, J. Dührkop

{"title":"On the Influence of the Soil Stratigraphy on the Monopile Deflection Investigated With FEM in a PISA Framework","authors":"M. Kanitz, Carlos Molina Mesa, Luís Berenguer Todo Bom, J. Dührkop","doi":"10.1115/omae2022-79329","DOIUrl":"https://doi.org/10.1115/omae2022-79329","url":null,"abstract":"\u0000 Large diameter monopiles are the most commonly used foundation type for offshore wind farms. The accurate representation of their response to lateral loading to optimise the required pile penetration plays a crucial role in the design of offshore wind farms. Recently, the PISA method proposed by Burd et al.[6] and Byrne et al. [5] has gained importance in the design of monopiles as it more accurately represents the interaction between the monopile and the soil than standard methods. In the PISA project, sand as well as soft and stiff clay were investigated through monotonic pile tests and the PISA parameters to represent the monopile-soil interaction curves were calibrated for each soil type investigated. Normally, the PISA parameters are derived separately for each soil type and then combined in a 1D model to include the soil stratigraphy. However, soil conditions on site are typically heterogeneous and the interaction between different soil layers with different strengths and stiffnesses should be captured. In order to gain a deeper understanding of the influence of soil stratification on pile deflection curves, this paper presents numerical simulations of a large diameter laterally loaded monopile embedded in layered soil using the finite element method (FEM) including a combination of soft clays and dense sands. Based on the FEM results, PISA parameters for the monopile-soil interaction curves are derived and implemented in a 1D beam model to calculate the pile deflection. The results are compared with a 1D model where the PISA parameters are first derived for the individual soil types and then combined to include the same soil stratigraphy. It is shown that the influence of soil stratification on pile deflection is significant. This paper highlights the need for calibration of PISA parameters considering the actual soil stratigraphy present on site.","PeriodicalId":427776,"journal":{"name":"Volume 9: Offshore Geotechnics","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115134587","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A Computational Framework for Integrated Analysis and Hybrid Testing of Mooring Line Foundations 系泊索基础综合分析与混合测试的计算框架

Volume 9: Offshore Geotechnics Pub Date : 2022-06-05 DOI: 10.1115/omae2022-79853

G. Abbiati, Zili Zhang, A. Franza, L. Andersen, H. Stutz

{"title":"A Computational Framework for Integrated Analysis and Hybrid Testing of Mooring Line Foundations","authors":"G. Abbiati, Zili Zhang, A. Franza, L. Andersen, H. Stutz","doi":"10.1115/omae2022-79853","DOIUrl":"https://doi.org/10.1115/omae2022-79853","url":null,"abstract":"\u0000 Positional restraint of floating structures is achieved using mooring systems anchored to the seafloor. Design and risk assessment of these systems is challenging due to variability in wave, wind loading, ground conditions leading to uncertainty in the load-displacement behaviour of mooring line foundations for design. Accordingly, new simulation tools shall be able to support risk-informed integrated analysis of the floating structure as a system of interacting components subjected to realistic dynamic excitation. Also, all components of the floating structure simulation model shall be supported by experimental validation. In response to this need, this paper presents a computational framework for simulating the dynamic response of floating structures up to two second-order hydrodynamic loading. The framework utilizes the finite-element method and supports both integrated analysis and hybrid testing with focus on mooring line foundations. Computational efficiency is the driving criterion for tailoring the fidelity of the element library. Results of an ideal case study are used to test computational efficiency.","PeriodicalId":427776,"journal":{"name":"Volume 9: Offshore Geotechnics","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126074073","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Numerical Modelling of Wave-Induced Liquefaction Around Pipelines and Offshore Cables 管道和海上电缆周围波浪液化的数值模拟

Volume 9: Offshore Geotechnics Pub Date : 2022-06-05 DOI: 10.1115/omae2022-78992

V. Kirca, Ş. Yılmaz, B. Sumer, Ranjith khumar Shanmugasundaram, H. Rusche, C. Windt, N. Goseberg

{"title":"Numerical Modelling of Wave-Induced Liquefaction Around Pipelines and Offshore Cables","authors":"V. Kirca, Ş. Yılmaz, B. Sumer, Ranjith khumar Shanmugasundaram, H. Rusche, C. Windt, N. Goseberg","doi":"10.1115/omae2022-78992","DOIUrl":"https://doi.org/10.1115/omae2022-78992","url":null,"abstract":"\u0000 Submarine pipelines and offshore cables are critical infrastructures for the offshore energy industry. Marine structures like pipelines and offshore cables buried in loose finegrained seabed soil, such as silt or fine sand, maybe under the threat of wave-induced liquefaction. Such failures (flotation or sinking of structures due to liquefaction) have been reported widely in the literature. Observations show that the presence of pipelines/cables can enhance the wave-induced liquefaction susceptibility. This paper presents early results of a numerical modeling study in which the liquefaction potential around a pipeline/cable buried in seabed soil is investigated. A numerical model being developed in the OpenFOAM CFD toolbox under the NuLIMAS (Numerical Modelling of Liquefaction Around Marine Structures) Project is utilized. The results show that the model is capable of simulating the pore pressure buildup around pipelines (or cables), both in near or far field. Additionally, it is shown that different wall boundary conditions of pipelines/cables (i.e. smooth or rough) can be modeled in the numerical model, which is a convenient feature of the model for utilization in practical applications.","PeriodicalId":427776,"journal":{"name":"Volume 9: Offshore Geotechnics","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124051938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0