Monopile Guiding Cage for Vertical Installation in Rocky Seabeds
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Solution Overview
Problem
Existing methods for installing offshore wind turbine foundations in rocky seabeds face issues such as instability of hole walls in loose soil layers, excessive cement consumption, cement deterioration in marine environments, and the need for substantial installation means and time to ensure verticality and stability of the piles.
Innovation Solution
A device for guiding and vertically maintaining a tubular monopile using a support structure with adjustable feet, a U-shaped positioning frame, a cage with damping pads and blades, and a method involving pre-installation of a metal reinforcement tube, vibration compaction of granular materials, and vibro-sinking to correct verticality defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If drilling is performed from a barge to install the pile, then the foundation can be installed in rocky seabed, but the hole walls become unstable in loose soil layer
Solution Approach 1:
The patent applies preliminary action by pre-installing a metal reinforcement tube (cage) into the drilled hole before removing the drilling equipment. This cage is then filled with compacted granular materials to stabilize the loose soil layer and prevent hole wall instability during subsequent monopile installation, eliminating the need for complex barge-based drilling and cementing operations.
2Reliability
If cement is used to seal the pile in the hole, then the pile is sealed in the seabed, but excessive cement is consumed and cement properties deteriorate in marine environment
Solution Approach 1:
The patent changes the material parameter from cement to compacted granular materials for sealing and stabilizing the seabed. This substitution eliminates cement consumption and avoids cement property deterioration in the marine environment, while achieving equivalent or superior stabilization through the granular fill combined with the metal reinforcement cage.
3Manufacturing precision
If substantial installation means are used to ensure verticality and stability during sealing, then the pile verticality is ensured, but installation time increases
Solution Approach 1:
The patent uses preliminary action by pre-installing the metal reinforcement cage and filling it with compacted granular materials before monopile installation. This preliminary stabilization structure provides inherent verticality guidance and stability during monopile installation, eliminating the need for substantial additional installation means and reducing overall installation time.
Solution Approach 2:
The patent introduces an intermediary structure (metal reinforcement cage filled with granular materials) that mediates between the drilled hole and the monopile. This intermediary provides verticality guidance and stability during monopile installation, replacing the need for complex real-time monitoring and adjustment systems.
4Manufacturing precision
If a device with cage and positioning frame is used to guide the monopile, then vertical alignment is ensured, but device complexity increases
Solution Approach 1:
The patent applies universality by designing the metal reinforcement cage to serve multiple functions: it acts as both the stabilization structure for the loose soil layer and the verticality guidance device for monopile installation. The positioning frame is integrated with the cage structure, eliminating the need for separate guiding devices and reducing overall system complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device stabilizes the monopile during installation, reduces cement usage, and ensures precise vertical alignment, allowing for efficient and time-effective installation of monopiles in rocky seabeds.
Implementation Method 1
The high portion of the cage comprises a plurality of damping pads distributed around the longitudinal axis of the cage, dimensioned to allow distributed contact with the monopile, and able to dampen the dynamics of the monopile
Implementation Method 2
arranging the granular material present in the cavity by vibration
Data Source
AI summary
A device is for guiding and vertically maintaining a tubular monopile when it is placed in an excavation made in a seabed, filled with compacted granular materials and consolidated by a metal reinforcement tube. The device includes a support structure mounted on four feet, each adjustable in height, a frame for positioning the support structure relative to the reinforcement tube having a closed U shape, and a cage mounted inside the support structure above the positioning frame to receive the monopile. The cage has a closed low portion and a high portion provided with a door to allow lateral introduction of the monopile into the cage.