Circular can-shape foundation and construction method for onshore wind turbines

摘要

Embodiments of the present foundation for onshore wind turbines comprise one solid cap structure, one tubelike upright cylindrical structure and a concrete corbel structure. All are constructed of high-strength cast-in-place reinforced concrete. The tubelike cylindrical structure has a purposely enlarged inner diameter than the wind turbine tower. The tubelike cylindrical structure has a wall thickness of 2 to 4 feet and embeds to the ground from 25 to 60 feet. The cap structure is constructed within the encompassed space of the tubelike cylindrical structure and seals the top of the tubelike structure. The anchor bolting system comprises anchor bolts, nuts, washers and embedment ring and is embedded in the reinforced concrete of the solid cap structure at the lower part and bolts the wind turbine tower flange to the solid cap structure. The corbel structure has a trapezoid shape in the section view with the top side is about 1 to 3 feet wider than the bottom side which is about 1 to 3 feet wide and is circumferentially arranged below the cap structure to reinforce the joints of the cap structure and the tubelike cylindrical structure. The ledge of the corbel starts from the outer edge beyond the embedment ring, and the lower part of the corbel structure extends to the tubelike cylindrical structure. A trenching method is tailored to construct the tubelike cylindrical structure, and guiding beams can be repeatedly used to direct the trenching, maintain the mud slurry level for trenching and provide a working mat for placement of the reinforcement cages, anchor bolting system and concrete. Other construction auxiliaries including mud slurry and water can be repeatedly utilized. The foundation constructed with the preferred embodiments can be used to support wind turbines and similar tower structures.