Double Top Suction Pile Foundation for Offshore Stability
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Solution Overview
Problem
Existing suction piles face unpredictable behavior and reduced stability due to the top bulkhead providing the load-bearing capacity, leading to potential deeper penetration into the seabed under structural loads, and challenging extraction processes.
Innovation Solution
Incorporating a pre-installed, fluid-permeable load-bearing surface below the top bulkhead within the suction pile, which transfers loads to the suction pile side wall or top bulkhead, enhancing stability and facilitating extraction by distributing loads more evenly and ensuring complete contact with the seabed soil plug.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the top bulkhead provides the load-bearing capacity, then the suction pile structure is simpler, but the foundation stability is reduced and unpredictable behavior occurs
Solution Approach 1:
The suction pile is segmented into distinct functional zones: the top bulkhead remains for sealing and suction generation, while a separate load-bearing surface (skirt) is introduced at a lower position to handle structural loads. This segmentation allows each component to perform its specialized function optimally, preventing the unpredictable behavior caused by the top bulkhead bearing loads.
Solution Approach 2:
The load-bearing function is moved from the vertical top surface (bulkhead) to a horizontal skirt surface at a lower elevation. This dimensional relocation allows the load-bearing surface to interact with the soil plug in a different spatial configuration, improving stability and preventing deeper penetration under structural loads.
2Device complexity
If the top bulkhead provides load-bearing capacity, then fewer components are needed, but deeper penetration into seabed occurs under structural loads
Solution Approach 1:
The load-bearing skirt is pre-installed at a specific position below the top bulkhead before the suction pile is installed into the seabed. This preliminary positioning ensures that when the structure is loaded, the skirt contacts the soil plug at the predetermined location, preventing uncontrolled deeper penetration while maintaining the simplicity of the overall structure.
3Device complexity
If the top bulkhead bears the structural loads, then the design is simpler, but extraction process becomes challenging
Solution Approach 1:
The load-bearing function is extracted from the top bulkhead and assigned to a separate skirt component. During extraction operations, this separation allows the top bulkhead to be pulled clear of the seabed while the skirt remains engaged with the soil plug, providing a controlled extraction process that is easier to manage than pulling the entire structure simultaneously.
4Reliability
If the load-bearing surface is fluid permeable, then fluid connection between suction spaces is improved, but load transfer mechanism becomes more complex
Solution Approach 1:
The load-bearing skirt is designed with fluid permeability, allowing water to pass through while still providing structural load-bearing capacity. This porous design maintains fluid connection between the suction spaces above and below the skirt, enabling reliable suction generation and distribution without requiring complex mechanical load transfer mechanisms.
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
This configuration increases the stability of the foundation, prevents deeper penetration into the seabed under structural loads, and simplifies the extraction process by ensuring equal distribution of overpressure within the suction space.
Implementation Method 1
vacuum or suction can be generated by removing water from within the suction space such that a resulting force tends to force the suction pile deeper into the subsea floor
Implementation Method 2
transfers loads to the suction pile side wall or top bulkhead, enhancing stability and facilitating extraction by distributing loads more evenly
Implementation Method 3
removal after use is made easier in that by pressing out the suction pile, the anchoring of the structure to the underwater bottom can be removed
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
Suction pile for installation in the seafloor to operate as a foundation or part of it to support an offshore structure resting onto the seafloor, the suction pile having internally near the top bulkhead (6) and spaced from this bulkhead (6) a load bearing surface (4) designed to keep the suction pile immovable while the offshore structure resting onto it is in full operation. The load bearing surface (4) could be the lower face of a fluid permeable slab which is in the space between the top bulkhead and the load bearing surface. Such slab could be obtained by fabrication in situ by casting a material against the top bulkhead (6).