Fujian Yongfu Power Engineering Co., Ltd. / offshore wind farm
changle, china
Project
Located in open sea off the Changle shoreline, Zone C of the Changle Offshore Wind Farm consists of 62 wind turbines, with a total installed capacity of 500 megawatts. The project site presented extreme environmental factors and complicated geological conditions. Fujian Yongfu conducted a feasibility study evaluating the structural integrity and cost-effectiveness of using a suction pile foundation and conduit frame for the turbines. They realized that their traditional soil simulation and strength assessment methods were not applicable to these pile structures and would result in a significant cost increase.
Facts
- Fujian Yongfu Power Engineering needed to build a large wind farm in an area prone to typhoons, earthquakes, and shifting soil.
- Initial work with traditional methods produced expensive designs, and other digital solutions could not unify modeling and soil analysis.
- The design team used PLAXIS and OpenWindPower Fixed Foundation to simultaneously model potential foundation options and analyze its effects on the ocean soil.
“OpenWindPower Fixed Foundation and PLAXIS allows engineers to take
advantage of their seamless interface to optimize the design of wind turbine
foundation structures such as single pile and suction pile.”
– Fan Xia Ling, Engineering, Fujian Yongfu Power Engineering Co., Ltd.
Solution
Though Fujian Yongfu had previously used Bentley’s OpenWindPower Fixed Foundation for offshore modeling, they discovered that pairing it with PLAXIS would give them a unified design environment that could allow them to
perform soil analysis and foundation design at the same time. Additionally, recent advancements in the applications included an integrated offshore structural and geotechnical design process for the design of large diameter
monopiles and suction tubes, which would enable the design team to fully realize and optimize their design intent.
Outcome
As a result of synchronized soil analysis and digital modeling, Fujian Yongfu determined that the best type of foundation for the project would be a three-pile suction conduit frame. Though this type of frame had only been
used in experimental environments within China, Fujian Yongfu used Bentley software to build it on a large scale and demonstrate its utility. Since this type of pile has a larger diameter but a shorter length than other piles typically
used for offshore wind facilities, they reduced the amount of steel needed for each foundation. Additionally, the design makes construction faster and easier, as it solves the problem of fatigue damage during pile driving and
eliminates the need for some staging platforms and larger construction equipment such as pile driving vessels.
By determining the feasibility of the three-pile suction conduit frame foundations, Fujian Yongfu ensured the wind turbines can withstand typhoons, shifting soil, and earthquakes. Compared to more traditional offshore wind turbine designs, the solution reduces costs by 30%, or more than CNY 400 million. Establishing 496 megawatts of clean energy in Fujian will eliminate the need to burn 535,000 tons of coal annually and cut down on carbon dioxide emissions from various power generation sources by 1,462,600 tons. The design also helped Fujian Yongfu minimize environmental impact by sustaining water quality, minimizing erosion, and protecting marine and avian life.
Software
PLAXIS
They first used PLAXIS to perform a full analysis of the soil in the construction area that could also measure the potential effects of design options.
OpenWindPower
Within that environment, they then simultaneously formed and optimized the design of the foundation in OpenWindPower Fixed Foundation while examining how the current state of the design would interact with the soil.
SACS
The design team used a suction pile module within SACS to automatically import PLAXIS analysis and create a composite model, which shows both the current state of the model and its effects on the soil around it. With this information, they adjusted the model to increase its strength and stability.
