Composite foundation and foundation reinforcement construction method for offshore wind turbines

Abstract

The invention relates to an offshore wind turbine composite foundation and a foundation reinforcement construction method. The composite foundation comprises a single-pile foundation body and a peripheral friction body, wherein the peripheral friction body is of a concrete integrated pouring structure with built-in steel bars and is in a circular truncated cone shape; the single-pile foundation body is sleeved with the peripheral friction body; the peripheral friction body makes contact with the upper end of a foundation soil body; vertical construction hole channels which communicate the upper end with the lower end and are used for achieving grouting are formed in the peripheral friction body; a plurality of vertical construction hole channels are evenly distributed on one or more circles of circumference; and a steel pipe nail is connected into each vertical construction hole channel in a pouring mode or fixedly inserted into each vertical construction hole channel, the lower section of each steel pipe nail extends out of the lower end of the peripheral friction body and is inserted into the foundation soil body, and guniting holes are evenly distributed in the pipe wall of eachsteel pipe nail. According to the composite foundation, the contact area between the foundation and a subgrade is increased, grouting reinforcement treatment can be conducted on the soft soil foundation, thus the bearing capacity of the subgrade and the foundation can be improved, integrated construction is achieved, and seabed pretreatment is reduced.

Description

technical field [0001] The invention belongs to the technical field of offshore wind turbine foundations, and in particular relates to a composite foundation for offshore wind turbines and a foundation reinforcement construction method. Background technique [0002] According to the survey results of wind energy, within the range of 5-25m and 2-50m in my country's offshore areas, the development potential of offshore wind power at heights of 50m and 70m has reached 200 million and 500 million kilowatts, respectively. The deep sea area is even more limitless. Due to the limitation of land resources, the development of offshore wind energy is in full swing around the world. Offshore wind turbine foundations include fixed and floating foundation structures. The specific foundation types include: monopile foundation structure, jacket foundation structure, tripod foundation structure, gravity foundation structure, column foundation structure, tension leg foundation structure, Se...

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Problems solved by technology

[0003] At present, the foundation form of wind turbines in nearshore wind farms is mainly based on single pile foundations. In some areas of my country, the seabed soil contains muddy soft soil and clay layers, especially in high compressibility areas with thick overlying layers. The foundation is not easy to stabilize the pile, and the bearing capacity is weak. To obtain sufficient bearing capacity, it is necessary to increase the piling depth to the bearing layer or even make rock-socketed piles, which greatly increases the cost

In order to improve the load-bearing characteristics of the single pile foundation, a composite single pile foundation was proposed in previous studies, which is composed of a single pile foundation body and a peripheral friction body sleeved outside the single pile foundation. The peripheral friction body is placed on the seabed. Provide an anti-overturning moment for the single pile foundation to improve the overall bearing characteristics of the foundation. However, the peripheral friction body may produce uneven settlement due to its own weight in weak soil and cannot effectively function

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