Embodiments of the present foundation for wind turbine generators comprise four structural members: a relatively long central hollow pier, several arm grade beams, a continued grade beam and a continued shear key. The central hollow pier positions in the center of the foundation system, arm grade beams are arranged evenly in radial direction and extend from the pier to the continued grade beam. Continued grade beam is arranged circumferentially in outer periphery and the continued shear key is built below it. Arm grade beams have a varied section with the far end embedding into ground. The top of the continued grade beam matches the top of arm grade beams, while the continued shear key embeds deeper into ground. All structural members are constructed of cast-in-place concrete reinforced with rebars, and all connections are fixed and rigid. The present foundation uses the ground to shape and form the structural members, no formwork, backfilling and compaction is needed.

A hole drilling device for forming an expanded-diameter hole portion at an inner bottom part of a mounting hole includes: a shaft including a contact surface and a tapered surface, and a cutter including a stopper provided on a side surface of the cutter, the stopper coming into contact with a surface of a drilling object. The cutter is movable between a first position and a second position. When the cutter is in the first position, the contact surface is in contact with the inner bottom part of the mounting hole, and the stopper is away from the surface of the drilling object. When the cutter is in the second position, the cutter has been pushed in forward from the first position, the cutting bit has protruded laterally from the tapered surface, and the stopper is in contact with the surface of the drilling object.

A hole drilling device for forming an expanded-diameter hole portion at an inner bottom part of a mounting hole includes: a shaft including a contact surface and a tapered surface, and a cutter including a stopper provided on a side surface of the cutter, the stopper coming into contact with a surface of a drilling object. The cutter is movable between a first position and a second position. When the cutter is in the first position, the contact surface is in contact with the inner bottom part of the mounting hole, and the stopper is away from the surface of the drilling object. When the cutter is in the second position, the cutter has been pushed in forward from the first position, the cutting bit has protruded laterally from the tapered surface, and the stopper is in contact with the surface of the drilling object.

Embodiments of the present foundation for wind turbine generators comprise four structural members: a relatively long central hollow pier, several arm grade beams, a continued grade beam and a continued shear key. The central hollow pier positions in the center of the foundation system, arm grade beams are arranged evenly in radial direction and extend from the pier to the continued grade beam. Continued grade beam is arranged circumferentially in outer periphery and the continued shear key is built below it. Arm grade beams have a varied section with the far end embedding into ground. The top of the continued grade beam matches the top of arm grade beams, while the continued shear key embeds deeper into ground. All structural members are constructed of cast-in-place concrete reinforced with rebars, and all connections are fixed and rigid. The present foundation uses the ground to shape and form the structural members, no formwork, backfilling and compaction is needed.

The invention relates to a foundation element in the ground and to a method for producing the foundation element which is formed of a hardenable mass, wherein, prior to hardening, at least one heat exchanger element is inserted. According to the invention a transition region towards the surrounding ground is provided, in which the foundation element is formed of crushed ground material of the surrounding ground with a hardening suspension.

The invention relates to a foundation element in the ground and to a method for producing the foundation element which is formed of a hardenable mass, wherein, prior to hardening, at least one heat exchanger element is inserted. According to the invention a transition region towards the surrounding ground is provided, in which the foundation element is formed of crushed ground material of the surrounding ground with a hardening suspension.

Embodiments of the present foundation for wind turbine generators comprise four structural members: one short central hollow pier, one continued grade beam, several solid piles built below the continued grade beam, and several arm grade beams linking the structural members. All structural members are constructed of cast-in-place concrete reinforced with rebars, and all connections are fixed and rigid. The short central hollow pier positions in the center of the system, functions as a hub to take the loadings and continuously to transfer and distribute the loadings further to the continued grade beam, arranged circumferentially in outer periphery of the system, and deeper to the solid piles, through the arm grade beams, which have a varied section and embed into ground in the far end. The present foundation utilizes the ground to shape and form the structural members, no formworks, backfilling and compaction is needed.

A retaining wall can include wall blocks positioned to retain material against a rear side of the wall blocks. A method for supporting such a retaining wall method includes attaching at least one of the wall blocks to at least one ground-stabilizing base body supporting the wall blocks. The ground-stabilizing base body can include a flexible cable attached to the rear side of at least one of the wall blocks and to a portion extending rearward away from the rear side of at least one of the wall blocks.

A retaining wall can include wall blocks positioned to retain material against a rear side of the wall blocks. A method for supporting such a retaining wall method includes attaching at least one of the wall blocks to at least one ground-stabilizing base body supporting the wall blocks. The ground-stabilizing base body can include a flexible cable attached to the rear side of at least one of the wall blocks and to a portion extending rearward away from the rear side of at least one of the wall blocks.

A pile includes a first pile section having a first end that engages a supporting medium and an opposing second end. A first end of a second pile section is engageable with the second end of the first pile section, each of the first and second pile sections having mating end fittings that create an interlocking fit. A sleeve overlays the first and second engaged ends of the first and second pile sections. At least one through hole aligned with at least one corresponding through hole of the first pile section is sized for receiving a fastener for securing the sleeve to the first pile section. In another version, the ends of the pile section are engaged in contact while the overlaying sleeve has a pair of interlocking sleeve or coupler portions that are configured to provide torsional resistance. Additional pile sections can be sequentially attached to the second pile section.