scholarly journals The Seepage and Soil Plug Formation in Suction Caissons in Sand Using Visual Tests

2020 ◽  
Vol 10 (2) ◽  
pp. 566
Author(s):  
Liquan Xie ◽  
Shili Ma ◽  
Tiantian Lin

The rapid development of offshore wind energy in China is becoming increasingly relevant for movement toward green development. This paper presents the results of visual tests of a suction caisson used as foundation for offshore wind turbines. The distribution of hydraulic gradients of sand at the mudline in the caisson was obtained to find out the relationship with the heights of soil plugs. The relationship equation was proposed and obtained by using quadratic regression, guiding project designs, and construction. It was found that there was no soil plug in the caisson when small suction was applied during the suction penetration. The relationship between the heights of the soil plugs and the hydraulic gradient of the soil was proposed and obtained by using quadratic regression to predict (roughly) the height of soil plugs in suction caissons in sand during suction penetration. The influence of settlement outside caissons on the soil plug was found to decrease as the buried depth rose.

2014 ◽  
Vol 1030-1032 ◽  
pp. 790-797
Author(s):  
Yasuyuki Nabeshima

Suction caissons attract the attention as the foundation of offshore wind turbines. Installation and resistance behaviors of the suction caisson are important factors for the design of foundation. An installation behavior into sandy seafloor was discussed by using a model suction caisson and the failure surfaces in the aluminum rod mass, as the model ground, subjected to lateral force were compared. Consequently, the installation of model suction caisson into sandy sea depended on the permeability of sandy seafloor and lateral resistance of suction caisson depended on the dimension of suction caisson which affected on the shape of failure surface in the ground.


2002 ◽  
Vol 26 (3) ◽  
pp. 145-155 ◽  
Author(s):  
Byron Byrne ◽  
Guy Houlsby ◽  
Chris Martin ◽  
Peter Fish

This paper outlines a £ 1.5m, three year, research project that commenced during the middle of 2002 to determine a design framework for shallow foundations for offshore wind turbines. The shallow foundations in focus are suction-installed skirted foundations otherwise known as suction caissons (Houlsby and Byrne, 2000). There are eight distinct themes to the research covering all aspects of the geotechnical performance of these foundations. The funding for the project has been obtained from the Department of Trade and Industry (£ 917k), Industrial Partners (£ 373k) and the Engineering and Physical Sciences Research Council (£ 221k). The results will feed into the design process for offshore wind turbines almost immediately.


2021 ◽  
Vol 275 ◽  
pp. 02006
Author(s):  
Xiaohui Ren

The rapid development of economy brings serious environmental pollution problem. Green innovation, as the connection point between government environmental regulation measures and sustainable green development of enterprises, has become one of the important choices for the transformation and development of enterprises. Based on the classic model of “prisoner’s dilemma” in game theory, this paper deeply analyzes the relationship between green innovation and performance. It is found that it is easy to get into trouble if only relying on the spontaneous green innovation within the enterprise. Applying appropriate pressure outside the enterprise can promote the change of green innovation and bring long-term benefits to the enterprise.


Author(s):  
Yuqi Wu ◽  
Qing Yang ◽  
Dayong Li ◽  
Yu Zhang

Suction caissons supporting offshore wind turbines are exposed to great horizontal loading above the soil surface, which may lead to overturning failure of the caisson. This paper presents a modified three-dimensional failure mechanism to analyze the anti-overturning bearing capacity of suction caissons. The modified failure mechanism is composed of meniscus-conical wedge having meniscus shape at the soil surface and scooped shape. The analytical solution to the anti-overturning bearing capacity of suction caisson is deduced in terms of the limit equilibrium method, following by a parametric study of wedge depth ratio (c) to optimize the critical failure mechanism that satisfies both the force and moment equilibriums. Thus, the methodologies are relatively easy to implement in traditional spreadsheets and the analyses tend to perform very fast. Meanwhile, the effects of gap formation at the rear side of the caisson, loading eccentricity and adhesion factor at caisson-soil interface on anti-overturning bearing capacity are investigated. Comparing with finite element limit analysis results, experimental data and existing theoretical solutions, it is proved that the presented limit equilibrium analysis can satisfactorily predict the anti-overturning bearing capacity of suction caissons with low aspect ratios for offshore wind turbines in uniform and linearly increasing strength clays.


2013 ◽  
Vol 353-356 ◽  
pp. 329-332
Author(s):  
Qing Lai Fan ◽  
Mao Tian Luan ◽  
Rong Chen

Skirted suction foundations are an attractive solution for floating offshore wind turbines that are subject to uplift due to overturning or buoyancy loading. Current industry design guidelines give conservative collapse loads for offshore shallow foundation systems, particularly due to neglecting the beneficial effect of suction developed within the soil plug during rapid uplift. The behavior of skirted rectangular and circular footings subjected to uplift loading has been studied using centrifuge model tests and upper bound plastic limit analyses. Results demonstrate that the shape effects on the uplift capacity factor are not significant when the circular and rectangular footings both obey reverse end bearing failure mechanism. Simple predictive methods based on existing bearing capacity theory are provided.


Author(s):  
Hongyan Ding ◽  
Lingqian Meng ◽  
Puyang Zhang ◽  
Conghuan Le

With continuous innovation and development of the wind power technology, the offshore wind turbine is rapidly developing. However, it also has difficulties in construction at sea and other shortcomings. One-step installation technique of the composite bucket foundation (CBF) provides a new way to solve the difficulties in the construction of offshore wind turbine at sea. And the integrated floating transport technique of the offshore CBF is the key link in the one-step installation technique. In this paper, by controlling three factors, such as draft, wave height and speed, the contact force between the vessel and CBF in the integrated floating transportation process is studied with experimental method. The relationship and the effect between the three factors and the contact force is analyzed. The experimental results are collected and analyzed to verify the safety of the integrated floating transportation of offshore CBF.


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