Rock-socketed single pile foundation of offshore wind turbines in batholith seabed and construction method thereof

Abstract

The invention relates to a rock-socketed single pile foundation of offshore wind turbines in batholith seabed and a construction method thereof. The rock-socketed single pile foundation comprises a steel pipe pile inserted in a moderately weathered batholith layer. An annular groove located at the periphery on the lower end portion of the steel pipe pile is formed in the batholith. An inner casing is nested within the lower end of the steel pipe pile. A gap is reserved between the inner casing and the inner wall of the steel pipe pile. The inside of the annular groove and the gap between the inner casing and the inner wall of the steel pipe pile are both filled with a high-strength grout having initial setting time of no less than 8 h. The rock-socketed single pile foundation of offshore wind turbines in batholith seabed in the invention is stable and reliable, ensures that the single pile foundation can be tightly bonded with the surrounding batholith, and reliably embedded in the moderately weathered batholith layer. The impact of a large boring diameter and a borehole perpendicularity error on the gradient of the single pile foundation and the problem of local stress concentration of the rock-socketed section of the steel pipe pile due to unevenness of the bored rock surface are reduced. Moreover, the cubic quantity of backfill concrete for the rock-socketed section can be lowered. The critical technical problem of use of the single pile foundation in the batholith seabed is effectively solved.

Description

technical field [0001] The invention relates to a rock-socketed single pile foundation for a sea-bed offshore fan and a construction method thereof. Background technique [0002] At present, there are mainly four types of wind turbine foundations used in offshore wind farms at home and abroad: pile foundation (including single pile foundation, jacket foundation, tripod foundation, etc.), gravity foundation, suction cylinder foundation and suspension foundation. Among them, the force analysis of the single pile foundation is clear, the structure type is simple, and the construction speed is fast. Foreign wind farms have applied monopile foundations to water depths of 0-40m, and the single-unit capacity of wind turbines is as high as 8MW; domestic wind farms also have rich experience in the construction of single-pile foundation soft foundation seabeds. According to statistics, more than 75% of the world's offshore wind turbine foundations are based on single pile foundations...

AI Technical Summary

Problems solved by technology

There may be rock formations with different degrees of weathering in the same plane, that is, one side is a harder rock formation and the other side is a softer rock formation. During actual pile sinking and drilling construction, different resistance or uneven settlement on both sides may cause The verticality of the single pile foundation does not meet the specifications and design requirements. There are relatively many uncontrollable factors during the construction process. It is difficult to control the verticality and hole diameter accuracy of the drilling. Stress concentration problems may exist locally in the section

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