Complex Modular Suction Pile and Convergent Offshore Wind Foundation Structures and Installation Technology

Abstract

The present invention relates to a composite modular suction pile and a fused offshore wind foundation structure system that innovatively improves the structural limitations and construction inefficiencies of existing monopile or jacket foundation methods in response to the trend of increasing the size of 10 MW to 20 MW class ultra-large offshore wind turbines. As offshore wind turbines become larger, complex external forces such as the self-weight of the superstructure, wind loads, waves, and earthquakes are increasing exponentially. The existing monopile method faces challenges such as skyrocketing manufacturing and transportation costs as water depth increases and encountering the physical limitations of super-large pile driving equipment, while the jacket method suffers from chronic problems including the risk of fatigue failure in complex welded joints and prolonged installation periods. In particular, conventional suction foundation technology carries risks of stress concentration and punching due to the simple direct connection between the caisson top and the connector body. Furthermore, the method of filling rubble by leaving the top of the suction pile open lacked design grounds regarding internal partition sagging and the powerful uplift force of super-large turbines. Additionally, there was a problem of very low feasibility due to the lack of specific construction methods for transporting and installing super-heavy loads of up to 5,000 tons at sea. To solve these problems, the present invention first adopts a Direct Design Method in which the measured data obtained from the Pizocone Penetration Test (PCPT), such as cone resistance (qc), sleeve friction (fs), pore water pressure (u2), and corrected cone resistance (qt), are directly projected into the design algorithm without a separate indirect conversion process. Through this, the accuracy of the design is raised to 90 to 95%, over-design is prevented, and the tip bearing capacity (Qp) and side bearing capacity (Qs) of the suction pile are precisely calculated by directly utilizing the measured values. For structural safety, high-strength steel is used, and at the same time, a suction pile local buckling prevention stiffener (10) is placed inside the suction pile (11), a sub-tower local buckling prevention stiffener (7) is placed inside the sub-tower (6), and a post-tower local buckling prevention stiffener (4) is placed inside the post-tower (3), respectively, and Von-Mises stress analysis and buckling stability evaluation are performed. In terms of the manufacturing method, the construction period can be drastically shortened by dividing the substructure into functional modules and producing them in parallel on land, and the suction pile (11), sub-tower (6), and post tower (3) are manufactured as separate modules and then joined through a specially designed ring connector (9). The ring connector (9) completely surrounds the outer diameter of the suction pile (11) to distribute the upper load to multiple suction piles, thereby ensuring structural integrity, and is designed so that the actual scour effect does not reach the foundation structure by attaching a scour prevention skirt plate (57) to the outside and penetrating it into the seabed by about 2 m. In addition, the connection between each module utilizes a stabbing cone (5) to ensure ease of upper and lower connection, and during the launching and installation phases, a precision buoyancy control system utilizing a pontoon (12) and a stabilizer (13) is applied, and strong buoyancy is secured by installing an air peg cone (18) on the upper part of the pontoon (12) and attaching an aramid fiber-reinforced polyurethane air peg (19) inside the suction pile (11) with a room-temperature curing adhesive (20) to maintain airtightness. During launching, the center of gravity and center of buoyancy are precisely controlled through the stabilizer (13), pontoon ballasting pipe (64), and valve (65). In particular, changes in the center of gravity (KG) and center of buoyancy (KB) are numerically predicted, and in sections where stability is unstable (GMT < 0), the suspension load of the marine crane (33) is applied to maintain the GMT at a positive (+) level, thereby preventing overturning accidents during launching and ensuring safe landing on the seabed. After landing on the seabed, the soil inside the pile is sucked out using the suction pump (30), manifold (29), and suction hose (31), thereby allowing it to be precisely driven to the required depth. After the penetration is completed, the self-weight is reinforced by filling the sub-tower (6) with unreinforced concrete (35) to offset the strong uplift force generated during operation, and finally, the strain and crack occurrence of the structure are monitored in real time through an intelligent sensor network consisting of a fiber optic sensor (FBG) (71), an acoustic emission (AE) sensor (72), and a wireless accelerometer (73), and this is reflected in a digital twin model to establish an intelligent predictive maintenance system that guarantees a design life of more than 25 years. This invention provides next-generation foundation design and installation technology capable of stably supporting ultra-large offshore wind turbines even under challenging ground conditions like those in Korean waters, by realizing noise- and vibration-free construction through such engineering convergence to minimize the impact on the marine ecosystem, contributing to a reduction in the Levelized Cost of Electricity (LCOE) of offshore wind power generation through shortened construction time via modular methods and optimized use of large equipment.

Description

Technology Field

[0001] The present invention relates to a composite modular suction pile and a fused offshore wind foundation structural system, and more specifically, to a composite modular suction pile and a fused offshore wind foundation structural system that calculates the bearing capacity, displacement, and stress values ​​of a suction pile by directly utilizing the values ​​of qc (Cone Resistance), fs (Sleeve Friction), u2 (Pore Water Pressure), and qt (Corrected Cone Resistance) obtained from the Piezocone Penetration Test (PCPT).

[0002] This invention provides next-generation foundation design technology that overcomes the limitations of existing monopile or jacket foundation methods and can stably support ultra-large offshore wind turbines of 10 MW to 20 MW class. The offshore wind industry is trending toward increasing turbine capacity to maximize power generation efficiency, and as turbines grow larger, the weight of the superstructure and wind loads increase exponentially. For example, the thrust generated when a blade with a diameter of 220 m rotates reaches approximately 45,000 kN (kilonewton) under conditions of an average wind speed of 8 m / s, and increases to over 87,000 kN at a rated wind speed of 13.5 m / s. Since these loads act simultaneously on the foundation structure in vertical and horizontal directions, threatening stability, long-term displacement control and stress distribution capabilities are essential, going beyond simply securing bearing capacity.

[0003] The PCPT test is a methodology for directly evaluating the strength and behavior of seabed soil, measuring four basic values: qc, fs, u2, and qt. These values ​​represent the strength and deformation characteristics of the soil, allowing for the analysis of soil behavior without the need to derive separate internal friction angle (Φ) or undrained shear strength (Su). For example, the tip bearing capacity can be calculated using the qt value and pile cross-sectional area, and the ultimate bearing capacity can be derived by calculating the skin bearing capacity using the fs value and skin area. Actual calculation results show that a single suction pile can exert a bearing capacity of millions of kN, demonstrating that this is sufficient to stably support ultra-large wind turbines.

[0004] In addition, the present invention ensures structural safety through Von-Mises stress analysis and buckling stability evaluation. It includes design technology that prevents buckling by adopting SM355 steel with a yield strength of 5545 mPa as the main material, performing structural verification according to Eurocode 3 and AISC standards to optimize the shell plate thickness, and placing ring stiffeners and H-beam reinforcements inside.

[0005] In addition, the present invention introduces a modular manufacturing method to overcome the inefficiency of manufacturing super-large structures. By dividing the substructure into functional modules, producing them in parallel on land, and assembling them at sea, the construction period can be shortened and quality reliability can be increased. In particular, to ensure the rigidity of the module joints, ring connector technology is applied to evenly distribute the load across multiple suction piles, and the design is configured to maintain bonding strength even in a corrosive seawater environment.

[0006] In offshore wind foundation construction, the launching and installation processes are the most critical stages, as instability can occur due to changes in the center of gravity (KG), center of buoyancy (KB), and metacenter height (GMT) when suspending the structure with an offshore crane or lowering it from a barge. This invention numerically predicts these factors and precisely controls the crane's suspension force to prevent overturning accidents, and includes real-time monitoring and fine leveling technologies utilizing suction pumps and sensors.

[0007] In addition, to maintain the structural integrity during long-term operation after installation, scour prevention technology and a fatigue crack detection sensor network for module joints were applied. In particular, underwater noise generated during the launching and installation process was minimized; when suction piles are driven into the seabed from a marine barge, the pump operation noise among the vibration noise is approximately 70 to 90 dB, but since this is connected to the suction pipe, it is not transmitted to the structure. Furthermore, since underwater noise is approximately 30 to 50 dB or less (similar to pump operation noise, lower than or similar to traffic noise), it is classified as an almost noise-free construction method. As it is recognized as an eco-friendly method in the Environmental Impact Assessment (EIA), an environmental engineering approach was also employed to reduce the impact on the marine ecosystem.

[0008] In conclusion, this invention is a next-generation offshore wind foundation structural technology that simultaneously achieves four goals—cost reduction, shortened construction time, minimized environmental impact, and stable support for ultra-large turbines—by combining a suction pile design theory that directly reflects PCPT test values ​​with modular fabrication and launching methods. Furthermore, through the comprehensive integration of civil, mechanical, marine, and materials engineering, it establishes a unique technological domain capable of optimization even under demanding ground conditions, including those found in Korean waters. Background Technology

[0010] With the recent commercialization of super-large turbines of 10 MW to 15 MW or more in the offshore wind industry, the requirements for foundation structures have become incomparably stricter than in the past. The increase in turbine size requires a new design paradigm that goes beyond a simple increase in output and must consider extreme conditions where complex external forces, such as the weight of the superstructure, wind load, wave load, current load, and seismic load, act simultaneously.

[0011] Conventional monopile foundations face rapidly increasing manufacturing and transportation costs as diameter and length increase, while jacket structures suffer from poor economic feasibility due to their complex fabrication and installation processes. To overcome these limitations, suction piles have emerged as an alternative. Suction piles utilize an eco-friendly principle of driving structures into the seabed using the difference in internal and external water pressure, offering low-noise and low-vibration construction while simultaneously enabling the application of large-scale structures.

[0012] The design and construction of suction piles cannot be explained solely by the shape and strength of the structure; the strength and behavior of the seabed must be precisely evaluated.

[0013] Looking at the conventional invention British GB 2615652A, the upper part of the suction pile is open, the middle is separated by a partition, and the lower part is also open, combining gravity and suction methods. However, when stones, concrete, sand, etc. are poured into the upper open part and penetrated into the ground to a certain extent, the middle partition separates the upper and lower parts, with the lower part functioning as a suction chamber and the upper part as a ballast receiving section. The necessity for specific suction pressure is not clear, and when stones, concrete, sand, etc. are poured into the upper open part, a structural problem may occur where the middle partition sags. Furthermore, although it is said that a rock berm or a seaweed-shaped curtain system is installed to prevent seabed erosion in the event of a gap between the arm and the seabed to prevent scour, the suction method is actually only feasible in soft ground, and there is no specific alternative regarding the settlement of the rock berm. Additionally, while the caisson and connector body are fabricated on land and then assembled, and the caisson is easy to manufacture as a simple cylindrical structure while the connector body is made as a box-shaped arm structure to ensure rigidity, the structure becomes very unstable because the caisson and the box-shaped arm structure are directly connected without reinforcement, which can lead to punching phenomena. Moreover, external environmental loads (earthquakes, waves, wind speed, currents) and pull-out loads are applied during nacelle operation (blade rotation); however, suction piles are very vulnerable to pull-out loads, and even if stones, concrete, or sand are poured into the open top, the weight is not clearly defined, which can cause problems with the suction pull-out load. In addition, structural issues and the net cell's displacement, displacement angle, natural frequency, and acceleration must be examined and the construction method proposed, but it was proposed without explanation regarding these aspects, and since the transportation and installation methods were not specifically presented despite the fact that the weight of the substructure and suction piles for the installation of an offshore wind power system of about 10 MW to 20 MW is about 4,000 to 5,000 tons, it is judged that it is practically difficult to realize.

[0014] On the other hand, the key role of the present invention lies in the PCPT (Piezocone Penetration Test), and through the PCPT test, the strength and deformation characteristics of the ground can be directly evaluated by continuously measuring the values ​​of qc, fs, u2, and qt, and through this, the behavior of the ground can be precisely analyzed without separate derived values.

[0015] Furthermore, to overcome the constraints arising during the manufacturing, transportation, and installation processes of super-large structures, the present invention introduces a modular manufacturing method by dividing the substructure into functional modules, manufacturing them in parallel on land, and then joining them at sea using ring connectors. This shortens the construction time and ensures high reliability of quality. Additionally, the ring connector is specially designed to maintain bonding strength even in a corrosive seawater environment by evenly distributing the load across multiple suction piles. Moreover, the ring connector is designed to surround the suction piles by forming them larger than their diameter, thereby preventing the suction piles from being punched and improving overall structural stability.

[0016] Despite the fact that launching is the most dangerous process in offshore wind foundation construction, no construction method for transportation has been developed in the past. During the launching and installation process, temporary instability may occur due to changes in the center of gravity (KG), center of buoyancy (KB), and metacenter height (GMT) when suspending the structure with a marine crane or lowering it from a barge. Therefore, the technology to numerically predict these factors and precisely control the crane's suspension force and buoyancy to prevent overturning accidents is a key background technology of this invention.

[0017] In conclusion, the background technology of the present invention aims for a comprehensive marine engineering system in which the geotechnical mechanics of the suction pile method, the load dynamics of a super-large turbine, the connection engineering of a modular structure, and the resilience control technology of offshore construction are organically combined. Prior art literature

[0019] Republic of Korea Patent Application No. 10-2631910 (January 26, 2024) 'Offshore Loading System and Launching Method for Offshore Floating Wind Power Generation Structures Using Semi-Submersible L-shaped Floating Dock Vessel' Inventor: Choi Byung-ryeol Republic of Korea Patent Registration No. 10-2471652 (November 23, 2022) 'Additional Structure Using Suction Bucket and Monopile Construction Method Using the Same' Patent Holder: Gentech Engineering U.S. Patent Registration No. 11,441,289 B2 (September 13, 2022) 'Hybrid Foundation for Offshore Wind Turbines' UK Patent No. 2300871.7 (January 20, 2023) 'Foundation for Offshore Wind Turbines' KRP Patent No. 10-1572723 (November 23, 2015) 'Group-type hybrid suction foundation equipped with variable blades and skirt section and method of installation thereof' EU Patent No. EP 3 052 374 B1 (August 26, 2014) 'Suction Pile' EU Patent No. EP 1 954 557 B1 (December 1, 2006) 'Suction Pile Installation and Suction Pile for use in Said method' US Patent Publication No. 2018 / 0195250 A1 (July 12, 2018) 'Modular Offshore Wind Turbine Foundation and Modular Substructure with Suction Caissons' International Patent Registration No. PCT / EP2025 / 069466 (July 8, 2025) 'Modular Fixed-Foundation Structure For Offshore Wind Turbine And Method For Installing Same' Korean Patent Publication No. 10-2017-0043708 (April 24, 2017) 'Platform for Floating Offshore Structure with Protruding Member and Semi-Submersible Offshore Structure Including the Same' Korean Patent Publication No. 10-2015-0137353 (December 9, 2015) 'Suction Foundation Using Vacuum Consolidation Method,"Construction method of the suction foundation and ground improvement method applying the suction foundation" Republic of Korea Patent Publication No. 10-2016-0118509 (October 12, 2016) "Suction foundation with improved magnetic settling performance and method of constructing the same" Republic of Korea Patent Registration No. 10-1918257 (November 07, 2018) "Suction pile having a structure for improving penetration performance using a vibration generator and method of constructing the same" Republic of Korea Patent Publication No. 10-2016-0010632 (January 27, 2016) "Separate launching, assembly, and installation method of a suction pile foundation structure utilizing the side of a barge" Republic of Korea Patent Registration No. 10-1630522 (June 8, 2016) "Suction foundation for preloading and method of constructing the same" Republic of Korea Patent Registration No. Korean Patent No. 10-1355132 (January 17, 2014) 'Suction bucket foundation for fixed offshore wind turbines' Korean Patent Registration No. 10-2461113 (October 26, 2022) 'Offshore substructure of an offshore wind turbine applicable to different installation methods and installation method of an offshore wind turbine using the same' Korean Patent Registration No. 10-2631910 (January 26, 2024) 'Offshore loading system and launching method for an offshore floating wind power structure using a semi-submersible inclined L-shaped floating dock' <Other Literature> Choi Byeong-ryeol, Seong Hong-geun, 2016. 03, “PCPT Mechanism and Pile Foundation Theory for Offshore Wind Power Generation”, The Korean Institute of Ocean Engineering. Choi Byeong-ryeol, 2023, “Offshore Soil Investigation Survey and Lab Test of Yokji Offshore Wind Power”, Gentech Engineering. Choi Byeong-ryeol, Lee Sang-hyeop, 2023, “Soil Properties and Pile Design Based on Pizocone Test Results Using DP2 Survey Vessel for Soil Mechanical Engineers”, Gentech Engineering, Ajou Construction. Jae Hyun Kim et al, 2010. “Bearing capacity of hybrid suction foundation on sand with loading direction via centrifuge model test”,The 15th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering.Krzysztof Trojnar , 2024. “New Hybrid Foundation Solutions for Offshore Wind Turbines”, Rzeszow University of Technology, Faculty of Civil and Environmental Engineering and Architecture .Kim, Jae-Hyun, 2023, “Bearing Capacity Evaluation of Hybrid Suction Bucket Foundations on Clay Under Horizontal Loads Using a Centrifuge”, JOURNAL OF THE KOREAN GEOTECHNICAL SOCIETY Vol.39, No.12, The problem to be solved

[0020] The main objective of the present invention is to overcome the limitations of existing monopile and jacket foundation methods under complex external force conditions such as waves, currents, and earthquakes, as well as the self-weight and wind load of the superstructure that increase exponentially due to the enlargement of ultra-large offshore wind turbines (10 MW to 20 MW class).

[0021] 1. Changes in Design Paradigms Due to the Introduction of Ultra-Large Offshore Wind Turbines and Overcoming Limitations of Foundation Structures The primary challenge that this invention aims to solve is to overcome the structural design limitations resulting from the increasing size of turbines (10 MW to 20 MW class or higher), which is a rapid trend in the recent offshore wind industry. As turbine capacity increases, the self-weight of the superstructure, including the nacelle and blades, increases exponentially, and due to the rise in hub height, the overturning moment acting on the lower part of the tower has reached a level exceeding existing design standards. The existing monopile foundation method faces physical and economic barriers, such as the manufacturing cost of large-diameter steel pipes and the volume limitations of ultra-large pile driving equipment, as water depth increases and loads grow. The jacket method also suffers from chronic problems, such as the risk of fatigue failure in welded joints of complex truss structures and prolonged installation periods. Accordingly, the present invention prioritizes providing a new level of foundation system capable of safely transmitting the combined load of a super-large turbine (dynamic load caused by wind, waves, currents, earthquakes, and blade rotation) to the ground, by completely overcoming the structural inefficiency of such conventional technology.

[0022] 2. Fundamental elimination of design uncertainty through the direct use of ground data. In the existing offshore foundation design process, ground parameters such as undrained shear strength (Su) and elastic modulus (E) were estimated through various empirical formulas and correlations based on limited sampling data obtained through boring. However, this indirect conversion process inevitably leads to design uncertainty, which causes an increase in construction costs by requiring the application of excessive safety factors to satisfy the strict tolerance and displacement angle limit conditions of super-large structures. To resolve such engineering inefficiencies, the core objective of this invention is to establish a technical system that directly projects actual data from the Pizocone Penetration Test (PCPT)—namely tip resistance (qc), sleeve friction (fs), pore water pressure (u2), and modified tip resistance (qt)—into a design algorithm without separate derivation integer conversion (Direct Design Method), thereby maximizing the accuracy of bearing capacity estimation and preventing over-design by continuously identifying the layered structure and drainage characteristics of the ground and precisely simulating real-time ground response.

[0023] 3. To address the structural defects and safety issues of conventional suction foundation technologies (GB 2615652A, etc.), the present invention aims to compensate for the fatal structural and construction defects exposed by prior art technologies with similar purposes, particularly GB 2615652A of the UK. First, the simple direct connection method between the upper part of the caisson and the connector body (box-shaped arm structure) in conventional technologies results in stress concentration due to the absence of reinforcement. This causes punching of the connection under repeated environmental loads, thereby increasing the risk of structural collapse. To solve this, the present invention aims to secure structural integrity by developing a special ring connector technology that completely encloses the outer diameter of the suction pile and evenly distributes the load to multiple piles. Second, conventional technology attempts to secure self-weight by opening the top of the suction pile and filling it with rubble or sand; however, this not only causes sagging and structural deformation of the internal partition but also fails to provide a specific basis for weight design capable of responding to the powerful uplift force generated in actual super-large turbines. The present invention aims to completely resolve the problem of interference between blade rotation and natural frequency (Soft-Stiff Design) by implementing a weight and shape design that optimizes uplift resistance based on precisely calculated numerical analysis results.

[0024] 4. Securing the feasibility of maritime transportation and installation of super-heavy loads (4,000 to 5,000 ton class). The total weight of the substructure and suction caisson to support 10 MW to 20 MW class turbines approaches approximately 4,000 to 5,000 tons. This presents extremely harsh conditions for fabricating the structure on land as a single unit or for lifting it with existing offshore cranes. Many prior art technologies only present the theoretical feasibility of the construction method and lack specific solutions on how to actually fabricate, transport, and install such super-heavy loads at sea. To address this, the present invention introduces a functional modular fabrication method, shortens construction time by dividing and fabricating major components in parallel to overcome the limitations of onshore fabrication sites, and systematizes a process for precisely combining them at sea. In particular, a key task is to track real-time changes in the center of gravity (KG) and center of buoyancy (KB), which are the most dangerous factors during the launching and lowering processes, and to secure active buoyancy and suspension control technology to prevent capsizing accidents in unstable sections where the metacenter height (GMT) decreases.

[0025] 5. Preservation of Marine Ecosystems and Securing Long-Term Operational Stability (Scour and Fatigue Failure) Existing impact pile driving methods generate severe underwater noise and vibration, causing immense damage to the marine biosphere. This is a major cause of project delays resulting from environmental impact assessments and public complaints. This invention aims to maximize the value of eco-friendly construction by realizing noise- and vibration-free construction through the advancement of the suction penetration method utilizing the difference in internal and external water pressure. Furthermore, regarding the scour phenomenon occurring at the junction between the seabed and the structure, simple measures proposed by conventional technology, such as rock berms or curtain systems, are vulnerable to settlement and long-term deformation problems in soft ground. The present invention aims to establish a system that safely guarantees a design life of over 25 years by attaching a skirt plate to the outside of a ring connector considering the strength characteristics of the ground, thereby penetrating it into the seabed to an actual scour depth of 2 m so that the effects of scour do not substantially affect the suction pile, and by protecting the structure from corrosion and fatigue failure that may occur during long-term operation as well as preventing scour through an optimal penetration depth design and a load distribution system.

[0026] 6. Reduction of construction costs and maximization of economic feasibility (reduction of LCOE). Ultimately, in order to lower the Levelized Cost of Electricity (LCOE) of offshore wind power generation, the present invention minimizes the usage time of large equipment used throughout the entire process from the fabrication to the installation of foundation structures and numerically manages construction risks. The simplification of the assembly process using ring connectors, the prevention of trial and error through precision construction based on PCPT, and the shortening of construction time through modular methods enable a significant reduction in overall project costs. The ultimate goal is to provide a technical foundation that secures the economic feasibility of constructing a super-large offshore wind farm.

[0027] For example, the present invention and fixed jacket offshore wind power are compared as follows regarding the reduction of construction costs and the maximization of economic efficiency (reduction of LCOE) based on one offshore wind turbine.

[0028]

[0029]

[0031] As a result of comparison in the above example table, the present invention can reduce construction costs by approximately 10% per offshore wind turbine. means of solving the problem

[0033] To solve the above problem, the present invention proposes the following technical means.

[0034] 1) The method of converting cone resistance values ​​(qc) measured by PCPT into N values ​​of the Standard Penetration Test (SPT) using existing empirical formulas for design purposes is the most vulnerable in terms of data reliability. Aside from the ease of comparison with onshore design data, the resolution of the raw data is severely degraded during the process of forcibly converting the dense, continuous stratigraphic information of the PCPT into discontinuous N values ​​at 1.5 m intervals. In particular, since offshore SPT has large errors due to energy efficiency losses, the method of using it by reverse calculation results in increased data distortion and uncertainty in the design of precision structures such as large-diameter suction piles.

[0035] 2) The method of deriving physical properties of the soil, such as undrained shear strength (Su) or internal friction angle (Φ), based on the measured values ​​of qt, fs, and u2 and applying them to the design is the most commonly used standard method in practice. This is highly suitable for use as input values ​​in general-purpose numerical analysis software, such as for soil-structure interaction (SSI) analysis or py curve generation. However, when determining correlation coefficients such as the cone index (Nkt), a process of comparison and calibration with boring data or laboratory test results at the site must be involved, and the success or failure of the design depends on the appropriateness of these calibration values.

[0036] 3) The method of calculating bearing capacity by directly substituting CPT measurements (qc, fs, u2, qt) into design formulas (UWA, ICP, CLAY, etc.) without a separate conversion step provides the highest accuracy. Since there is no data loss and minute changes in the soil layers can be immediately reflected in the design, it most practically simulates actual soil resistance when reviewing installability, which is a critical risk for large-diameter piles with a diameter of 5 m or more. Therefore, global marine engineering guidelines (DNV, API) recommend this direct method as the top priority for the design of large-diameter foundations. The reliability of the three methods mentioned above is explained in the table below.

[0037]

[0038] Accordingly, the present invention precisely calculates the bearing capacity, displacement, and stress of a suction pile by directly reflecting the values ​​of qc, fs, u2, and qt obtained from the Pizocone Penetration Test (PCPT), a PCPT-based design method, into the design formula without intermediate conversion. It secures the ultimate bearing capacity (Qult) by calculating the tip bearing capacity (Qp) using qt and the tip area (Ap), and the skin bearing capacity (Qs) using fs and the skin area (As,out), and calculates the optimal suction size through numerical analysis as follows.

[0039] Review of the vertical resistance of the suction pile

[0040] qc = Cone resistance (value obtained from PCPT investigation)

[0041] u2 = excess gap water pressure (value obtained from PCPT survey results)

[0042] qt = q c +(1-a)*u2

[0043] fs = Sleeve friction (value obtained from PCPT survey results)

[0044] Qp = qt*Aannual (KN)

[0045] Qp = qt*Ap when Unplugged and top close

[0046] Qs fs cpt Asout(KN)

[0047] Qult = Qp+Qs

[0048] Qu = ηv(Qs + Qp)

[0049] ηv = (0.5+0.032*n)+(0.1-0.003*n)*LN(S / D) Influence of vertical group piles

[0050] n = number of suction files

[0051] S / D = Suction file distance / Suction file diameter

[0052] Q all = Qu / SF =Qu / 2 ≥ Pv OK

[0053] Q uplift = ∑fscpt*Asout+ ∑fscpt*As*MIN(∑ΔZ, ∑ΔZp) (KN), As=π*D

[0054] Qauplift, Quplift / SF, SF=2≥ PL OK

[0055] α = s^p / (s^p+f^q)

[0056] β = f^q / (s^p+f^q)

[0057] p = 2 for S>f

[0058] 1 for s<f

[0059] q = 1 for S>f

[0060] 2 for s<f

[0061] s = min(qt / qtref(=350 kPA),smax=1.5)

[0062] f = min(Rf / Rfref(=2%),fmax=1.3)

[0063] w = α*s+β*f=s^2 / (s+f)+f^2 / (s+f)

[0064] When, p=q=1

[0065] aH = 0.8+0.4*w

[0066] bH 1.0+0.5*w

[0067] aM = 0.08+0.04*w

[0068] bM = 1.8+0.4*w

[0069] 석션 파일의 측방향 저항력 검토

[0070] CH = fH(LD)= aH *(L / D)^bH=

[0071] CM = fM(LD)=αM*(L / D)^bM

[0072] Hult = D*∑(qt* CH *ΔZ)(KN)

[0073] Mult = D*∑(qt* CH *ΔZ)*∑(ΔZ), (Kn - M)

[0074] Unit Check(ISO 19909or DNV-RP-E303)

[0075] Hult = m(Hult) (KN), m=Lateral Grup Effect

[0076] Mult = Mult = m(Mult), m=Lateral Grup Effect

[0077] m = (0.45+0.05*n)+(0.12-0.002*n)*LN(S / D) Horizontal (lateral) group pile influence

[0078] n = number of suction files

[0079] S / D = Suction file distance / Suction file diameter

[0080] Unity Check = SF*(H / (Hult) + M / (Mult )), SF=1.15

[0081] Lateral displacement of the suction pile, y(z)

[0082] Kh = Ave(C*qt / D)(KN / m3), by Robertson (1990 2009)

[0083] C=10*exp(0.05*qt) by Kulhawy & Mayne (1990) - Foundation Design Manual

[0084] λ(z) = (kh(z)*D / EI)^(1 / 4) (1 / m)

[0085] y(z) = PL / (6EIλ^4)*(3-3λz+(λz)^3)*exp(-λz)+Mt*(1-λz)*exp(-λz) / (2EIλ^3), (m) Lateral allowable displacement of the suction pile, Y all = 35 mm where D≤1.2 m, or 3% of D where D≥1.5 m

[0086] By applying the theory described above, the suction pile is made capable of sufficiently withstanding the load acting on it.

[0087] The following is a technique for ensuring structural stability: It meets the yield strength criteria of SM355 steel through Von-Mises stress analysis and buckling stability evaluation. Buckling prevention design is performed by optimizing shell plate thickness and placing ring stiffeners (channels) and H-beam reinforcements.

[0088] Stress review of unreinforced cylindrical shells

[0089] σN = [FL-(Lift,clay+Lift, sand) / 2] / As (MPA)

[0090] As =π*t*(Dt)(m2)

[0091] σb = M / Z (MPA)

[0092] Z=π*(D^4-(D-2t)^4) / (32*D)

[0093] M(Mn - M) Bending Moment at Top of Suction

[0094] τ = H / As (MPA),

[0095] H = Lateral Load at Top of Suction(MN) .

[0096] As=π*t*(Dt)(m2)

[0097] σmax = σN+σb (MPA)

[0098] σvm = (σmax^2+3*τ^2)^0.5

[0099] γm = 1.1

[0100] The snow fell on the ground in the woods

[0101] (Fhe) = 2*ChE*E*(t / D)(MPA)

[0102] (Fxe) = 2*ChL*E*(t / D)(MPA)

[0103] = π^2*E / (KL / r)^2

[0104] = π^2*E / (KL / (t / 3.4641))^2

[0105] r = √(I / A)=t / 3.4641

[0106] ChE = 1 / √(3*(1-ν^2))

[0107] Poisson Ratio, ν=0.3

[0108] ChL = 0.1274*LN(Ls / D) + 0.2533 when Hinged

[0109] = 0.1274*LN(Ls / D) + 0.3033 when Fixed

[0110] = π^2 / (2*(t / D)*(K*Ls*r)^2)

[0111] = π^2 / (2*(t / D)*(K*Ls* (t / 3.4641))^2)

[0112] r = √(I / A)=t / 3.4641

[0113] Fe = 0.55*Fy(MPA)

[0114] Fine = 1.6*Fy(MPA)

[0115] σcr = π^2*E / (K*Ls / r)^2

[0116] = π^2*E / (K*Ls / ( t / 3.4641))^2

[0117] r = √(I / A)=t / 3.4641

[0118] σcr < 1.6*Fy

[0119] σcr ≥ 1.6*Fy

[0120] Fxc = Fy*(1 - 0.278*(Fy / Fxe)

[0121] σθ = Δp*R / t / 1000(MPA), Applied Pressure Δp

[0122] σx = Δp*R / (2t) / 1000(MPA)

[0123] σvM,mem = (σθ^2-σθ*σx+σx^2)^0.5 (MPA)

[0124] The buckling strength of an unreinforced cylindrical shell under external hoop pressure is determined by geometric and material properties such as the shell's radius, thickness, material elastic modulus, and Poisson's ratio, and is calculated according to elastic buckling theory. The basic formula is presented in the form of calculating the critical external pressure pcr.

[0125] p cr,elastic= 2*E / (√3*(1 - ν^2))*(t / R)^3(MPa)

[0126] E = 210,000 mPa (high pressure)

[0127] ν = 0.3(low-frequency)

[0128] pRd = η*p cr,elastic / γ M (MPA), η = 0.6, γ M =1.1

[0129] σ'v=∑(γw*(0.27*Log(fscpt / qt*100)+0.36*Log(qt / Pa)+0.235)*ΔZ) (KPA)

[0130] Pext =[γ SF *Δp+∑(γw*(0.27*Log(fscpt / qt*100)+0.36*Log(qt / Pa)+0.235)*ΔZ) - Pint] / 1000 (MPA)

[0131] Pext=[γSF(=1.35)*Δp+∑(γw*(0.27*Log(fscpt / qt*100)+0.36*Log(qt / Pa)+ 0.235)*ΔZ) - Pint] / 1000 (MPA);

[0132] UC = Pext / pRD

[0133] σh = Pext*D / (2*t)(MPA) ≤Fy / 1.1

[0134] Pcr 2*E / (1 - υ^2)*(t / D)^3 (MPA)≥Pext Ok

[0135] σcr = E / (3(1 - ν^2)*2*t / D (MPA) ≥σN+ σb OK

[0136] 보강재가 있는 쉘의 베이 탄성 좌굴

[0137] p cr,bay = p cr,elastic *(1+β*(R / s)^2) (MPA)

[0138] S = Stiffener Spacing(m)

[0139] β = kbc*[β0+γ*(Es*Is / (E*t^3*s))^m]

[0140] β=kbc*[β0+γ*(Es*Is / (E*t^3*s))^m]

[0141] kbs=0.65 H - H, kbs=1.0 F - F, kbs=0.8 H - F, where H - H is the state where both ends of the reinforcing member are hinged, F - F is the state where both ends of the reinforcing member are fixed, and H - F is the state where one end of the reinforcing member is hinged and the other end is fixed.

[0142] Reference buckling factor β0 = 0.9, stiffness ratio influence scaling factor γ = 1.0,

[0143] Sensitivity index m=1 / 3

[0144] Is= I x,S +I plate +A plate *d plate ^2

[0145] I x,S = Moment of Inertial for Stiffener, I plate =S*t^3 / 12, A plate =S*t,

[0146] d plate = natural axis to plate center

[0147] Zs = Is / c

[0148] c= ∑(Ai*yi) / ∑Ai

[0149] p Rd, bay = η*p cr,bay / γ M (MPA)

[0150] η=0.6, γ M =1.1

[0151] Smax= R*((γ M / η*Pext) / (β*p cr,elastic )-1)^0.5 (m), γ M =1.1, η=0.6

[0152] β=0.8 for Fixed - Fixed

[0153] β=0.7 for Fixed - Hinged

[0154] β=0.6 for Hinged - Hinged

[0155] Smax=((k*π^2*E*1000) / (12*(1 - ν^2))*((t / 1000)^2 / (Fy / 1.5)))^0.5 (m)

[0156] when (γM / η*Pext) / (β*p). cr,elastic ) -1<0

[0157] k=4 for Fixed - Fixed

[0158] k=2 for Fixed - Hinged

[0159] k=1 for Hinged - Hinged

[0160] σh = Pext*D / (2*t) * (1- η)(MPA) ≤Fy / 1.1,1.

[0161] η=Aeff / (Aeff+t*S) *F2,

[0162] F2=2*(coshθ*sinθ+sinhθ*cosθ) / (sinh2*θ+sin2*θ),

[0163] θ=1,285*S / (D*t)^0.5

[0164] Aeff=Astif+t*S

[0165] Pcr=2.42*E / (1 - υ^2)^(3 / 4)*(t / D)^2.5 / (S / D - 0.45*(t / D)^0.5) (MPA)≥Pext OK

[0166] σcr = (Kp+kc)*π^2*E / (12*(1 - ν^2)) *(t / S)^2(MPa)

[0167] kc=12*(S^2 / (R*t)*(1 - ν^2)^0.5)^2 / π^4 ≥σN+ σb OK

[0168] 쉘 구조에서 보강재 단면 치수(강도) 산정

[0169] q = Pext* S (KN / m)

[0170] Vmax = q*π*R

[0171] Vmax = P / 2

[0172] Vmax = q*R*Φ / 2, 0≤Φ≤2π

[0173] Vmax = q*κeff*π*R, κeff =F - F= 1.0, H - F = 0.8, H - H = 0.6

[0174] U.Cs = (Vmax / AS) / (Fy / √3)≤1.0, OK

[0175] Mθ,max = α*q*R(Kn - M / m)

[0176] α = 0.5

[0177] α = 0.25

[0178] α = 0.318

[0179] α = 0.25*(Φ+sinΦ) / (2π), 0≤Φ≤2π

[0180] α = 0.2

[0181] Zreq ≥ Mθ,max / sallow(m3 / m),sallow=Fy / 1.5

[0182] Ireq ≥ γ s *S*t^3 / 12, (m4 / m) c s =5

[0183] Is = I x,S +I plate +A plate *d plate ^2 ≥ Ireq

[0184] I x,S = Moment of Inertia for Stiffener, I plate =S*t^3 / 12, A plate =S*t, d plate = natural axis to plate center

[0185] Zs = Is / c ≥ Zreq

[0186] c = ∑(Ai*yi) / ∑Ai

[0187] Rim line (boundary of a circle) - Load generated by a load applied to the center

[0188] A = FL / (2πR) = FL / (πD)(KN / m)

[0189] B = M / (πR^2) = 4M / (πD^2)(KN / m)

[0190] σtmax = A+B(KN / m)

[0191] σmmax = AB(KN / m)

[0192] τin-pl= H / (2πR)= H / (πD)(KN / m)

[0193] σmem,max = σtmax / tcover (Mpa)

[0194] τmem = τ in-pl / t cover (MPA)

[0195] σvM,mem= (σ mem,max ^2 + 3*τmem^2)^0.5

[0196] Von Mises design strength, Fyd = Fy / γm, γm = 1.1

[0197] r = (smax^2+v^2)^0.5 (KN / mm)

[0198] Weld Size = r / (Fwy*0.708*0.3)(mm)

[0199] Review of upper cover plate without reinforcement due to Δp (pressure difference) during installation

[0200] D = E*t^3 / (12*(1 - ν^2)) (Mn - M)

[0201] Cw = 5 / 384(Hinge) = 1 / 384(Fixed)

[0202] Cm = 3 / 16(Hinge) = 1 / 16(Fixed

[0203] wmax = Cw*Δp*R^4 / D(m), Wallow =D / 200

[0204] D = Suction Diameter

[0205] Mmax = CM*Δp*R^2 (Mn - M)

[0206] σmax = 6*Mmax / tc^2

[0207] σallow=Fy / 1.5

[0208] Review of upper cover plate without reinforcement due to design load during operation

[0209] Cw(P) = 1 / (8π) for Hinged = 1 / (16π) for Fixed

[0210] Cw(M) = 1 / (π) for Hinged = 1 / (2π) for Fixed

[0211] CM(P) = 1 / (2π) for Hinged, = 1 / (4π) for Fixed

[0212] CM(M) = 1 / (π*R) for Hinged, = 1 / (2π*R) for Fixed

[0213] CQ(P) = 1 / (π*R) for Hinged, = 1 / (π*R) for Fixed

[0214] wmax(P) = Cw(P)*Pv / Dplate(m)

[0215] Pv = Vertical load on the upper cover plate, D plate = Upper cover plate diameter

[0216] wmax(M) = Cw(M)*Mo / Dplate(m)

[0217] Mo = moment at top cover plate, D plate = diameter at top cover plate

[0218] wmax = wmax(P)+wmax(M) (m)≥ D / 200 OK

[0219] Mr(0), Mθ(0) = CM(P)*Pv*R(Mn - M)

[0220] Pv=Vertical Load at cover plate

[0221] Mr(0), Mθ(0) = CM(M)*Mo(Mn - M)

[0222] Mo=Moment at cover plate

[0223] σr±(0) = ±6*Mr(0) / t^2 (MPA)

[0224] Qr(0) = CQ(P)*Pv (KN)

[0225] Pv=Vertical Load at cover plate

[0226] σrmem = Qr(0) / (π*D*t)

[0227] τavg = Qr(0) / (b*t) (MPA), b=unit length=1m

[0228] σθmem = H / (2*π*r*t) (MPA)

[0229] H=Horizontal Loat at cover plate

[0230] σrtot,(0) = σrmem±6*Mr(0) / t^2

[0231] σθtot,(0) = σθmem±6*Mθ(0) / t^2 (MPA)

[0232] σvM(0) =√(σrtot,(0)^2+σθtot,(0)^2 - σr*σθ+3* τavg ^2)

[0233] Von Mises design strength, Fyd = Fy / γm, γm = 1.1

[0234] Review of grid-type reinforcement of circular cover plate due to differential pressure (Δp) during installation

[0235] D' = √(π*D^2 / 4)

[0236] Nsti = D / s - 1

[0237] w = w=(Δp*π*D^2 / 4) / (D'*Nsti*N)

[0238] Applied Pressure Δp

[0239] N = 2 for Grillage Grid, Otherwise 1

[0240] Hinged Mmax = w*D'^2 / 8 (Kn - M)

[0241] Fixed Mmax = w*D'^2 / 12 (Kn - M)

[0242] σrmem = Mmax / Zs

[0243] Is = I x,S +I plate +A plate *d plate ^2 ≥ Ireq

[0244] I x,S = Moment of Inertial for Stiffener, I plate =S*t^3 / 12, A plate =S*t,

[0245] d plate = natual axis to plate center

[0246] Zs = Is / c ≥ Zreq

[0247] c= ∑(Ai*yi) / ∑Ai

[0248] Hinged wmax = 5*w*L^4 / (384*E*Ixx) (m)≤ D / 200 OK

[0249] L=D

[0250] Fixed wmax = 5*w*L^4 / (9216*E*Ixx) (m) ≤ D / 200 OK, L=D

[0251] Zreq = Mmax / σallow (m3) ≤ Zs OK

[0252] σallow=Fy / 1.1

[0253] τavg Q / (π*D*t)=(Δp*D) / (4*t)

[0254] σθmem = H / (π*D*t)=H / (2*π*r*t)(MPA)

[0255] σvM(0) =√(σrmem^2 + σθmem^2 - σrmem * σθmem +3* τavg ^2)

[0256] Von Mises design strength Fyd = Fy / γm

[0257] Review of grid-type reinforcement for the panel strip of the upper circular cover plate due to Δp (differential pressure) during the installation process

[0258] Mstrip = Δp*S^3 / 8 (Kn - M)

[0259] Applied Pressure Δp

[0260] S = Spacing of stiffener on cover plate

[0261] M strip = Δp*S^3 / 12 (Kn - M)

[0262] Applied Pressure Δp

[0263] S = Spacing of stiffener on cover plate

[0264] σ maxpanel = 6*Mstrip / (S*t^2)(MPA)

[0265] τpanel,avg = Δp*S / (2*t) (MPA)

[0266] Applied Pressure Δp

[0267] S = Spacing of stiffener on cover plate

[0268] σvM(0) = √(σmaxPannel^2+3*τpannel^2)

[0269] Von Mises design strength, Fyd = Fy / γm

[0270] The lattice-type reinforcement installed on the circular cover plate under operating conditions is examined as follows.

[0271] W = PV / N

[0272] W = PV

[0273] N = 4 for Grillage Grid, Otherwise 2

[0274] Mc = Mo / N

[0275] Mo= Moment at top of Suction

[0276] Mc = Mo

[0277] Mo= Moment at top of Suction

[0278] Mmax = Pv*D / (4*N) (Kn - M)

[0279] N=2 When Grillage Grid,Otherwise N=1

[0280] Mmax = Pv*D / (4*N) + Mo / N (Kn - M)

[0281] N=2 When Grillage Grid,Otherwise N=1

[0282] Mmax = Pv*D / (8*N) + Mo / N (Kn - M)

[0283] N=2 When Grillage Grid,Otherwise N=1

[0284] Mmax = Mo (Kn - M)

[0285] S(m) = Top Plate Stiffener Spacing

[0286] σrmem = Mmax / (Zs or Zsuc)

[0287] Zreq = Mmax / σallow (m3)

[0288] σallow=Fy / 1.5

[0289] Is = I x,S+I plate +A plate *d plate ^2 ≥ Ireq

[0290] I x,S = Moment of Inertia for Stiffeners, I plate =S*t^3 / 12, A plate =S*t,

[0291] d plate = natural axis to plate center

[0292] Zs = Is / c ≥ Zreq

[0293] c = ∑(Ai*this) / ∑Ai

[0294] Isuc = π*(D^4-(D-2*t)^4) / 6

[0295] Moment of Inertia of Suction

[0296] Zsuc = Isuc / (32*D)

[0297] Section modulus of Suction

[0298] w = W*D^3 / (48*E*Ixx) (m) ≤ D / 200 OK for Hinged.

[0299] w = W*D^3 / (192*E*Ixx) (m) ≤ D / 200 OK - Fixed

[0300] w = Mo*Ls^2 / (2*EI)+H*Ls^3 / (3*E*Isuc) (m) ≤ Ls / 200 OK

[0301] Mo=Life snowflake

[0302] H= 석션 ਸุุุุุุิรุุาาาา

[0303] Ls= Length at Suction

[0304] Isuc = Moment of Inertia for Suction

[0305] τavg = Pv / (π*D*t) (MPA)

[0306] τavg = H / As (MPA)

[0307] σθmem =H / (π*D*t) = H / (2*π*r*t)(MPA)

[0308] σvM(0) =√ (σrmem^2 + σθmem^2 - σrmem * σθmem +3* τavg^2)

[0309] Von Mises design strength, Fyd = Fy / γm

[0310] Review of grid-type reinforcement applied to the panel strips of the upper circular cover plate for loads occurring during operation

[0311] σmax,panel = Pv / (S*D)*S^2 / (2*t^2) (MPA)

[0312] σmax,panel = △P*S^2 / (2*t^2) (MPA)

[0313] τavg = Pv / (π*D*t)

[0314] τavg = (△P*π*D^2 / 4) / (π*D*t)

[0315] σθmem = H / (π*D*t) (MPA)

[0316] σvM(0) =√(σ max,panel ^2+ σθmem^2 - σ max,panel *σθmem +3* τavg^2)

[0317] Von Mises design strength, Fyd = Fy / γm

[0318] Structural strength was secured using the above formula with the outer plate and inner channel reinforcement of the suction, the upper plate, and the reinforcing H-beam.

[0320] The technical core of this invention is to optimize the penetration process and final bearing capacity of a foundation structure by utilizing the values ​​of qc (cone resistance), fs (sleeve friction), and u2 (pore water pressure) obtained in advance from the PCPT (Piezocone Penetration Test). Specifically, this system does not judge the condition of the ground based on abstract concepts such as simply being good or bad, or on the subjective experience of the operator; instead, it operates by inputting the physical values ​​of qc, fs, and u2, which are measured on-site, into the system as direct design variables and control factors.

[0321] First, to establish a precision control mechanism based on actual measured parameters, the correlation between cone resistance (qc) and sleeve friction (fs) is analyzed to quantify the layered structure of the ground and changes in soil quality at the micro-level depth. Through this, the subsurface resistance expected to occur at each depth of suction pile penetration is calculated in advance, thereby enabling precise penetration design based on data rather than simple pressure variation.

[0322] In addition, the present invention optimizes the penetration process through dynamic data feedback. While conventional suction pile construction methods were limited to passive control that vaguely increased or decreased suction pressure in accordance with ground resistance, this system immediately compares and analyzes the actual penetration depth and internal negative pressure of the suction piles, measured in real time, with previously calculated ground resistance prediction data. If the actual penetration depth falls short of the target value or if there are signs that the horizontal alignment of the structure is deviating due to ground heterogeneity, the system re-references the qc value assigned to each suction pile to recalculate the optimal negative pressure capable of overcoming the resistance and automatically feedback-corrects the output of the suction pump.

[0323] Finally, the safety of construction is dramatically ensured through precise monitoring of pore water pressure (u2). By tracking the u2 value, which changes in real time during the penetration process, the condition of excess pore water pressure inside the ground is diagnosed, thereby detecting in advance the heaving or piping phenomena that may occur during suction. These actual measurement data act as safety thresholds within the control algorithm, thereby completing an intelligent construction mechanism that prevents ground failure while simultaneously guiding the ultra-large offshore wind foundation structure to be installed while maintaining optimal speed and precise horizontality.

[0324] The algorithm flowchart shown in the attached Fig. 57 illustrates an intelligent construction mechanism that maintains an optimal penetration state through real-time feedback by utilizing actual ground data (qc, fs, u2) as design variables. It represents the construction of an intelligent suction pile penetration control system algorithm based on actual PCPT data, which is an optimization process that fundamentally prevents construction risks such as deviation from horizontality and heaving caused by ground heterogeneity by precisely predicting subsurface resistance at different depths based on previously acquired PCPT parameters, and actively controlling the output of the suction pump by comparing and analyzing negative pressure and pore water pressure data measured during the actual penetration process in real time.

[0325] In addition, in the case of offshore wind structures, the displacement and displacement angle of the structure must be within the allowable values ​​of the nacelle so as not to interfere with the operation of the nacelle.

[0326] The displacement calculation is as follows.

[0327] δ=Ht*L^3 / (3*E*Isub)

[0328] δ=Mt*L^2 / (2*E*Isub)

[0329] δ=Hm*b^2*(3*Lb) / (6*E*Isub)

[0330] δ=Mm*(Lb) / (E*Isub)

[0331] The displacement angle is calculated using the following formula.

[0332] θ=Ht*L^2 / (2*E*Isub)

[0333] θ=Mt*L / (E*Isub)

[0334] θ=Hm*b*(2L-b) / (4*E*Isub)

[0335] θ=Mm / (E*Isub)

[0336] Examples of displacement and displacement angle calculations are as follows.

[0337] Also, the allowable acceleration of the nussel due to earthquakes or vibrations is 0.3 g during operation and 0.7 g in extreme conditions, and detailed calculations are shown as an example below.

[0338]

[0340] Next, the natural vibration of the composite modular suction and fused offshore wind foundation structure must satisfy the allowable value of the nucleus.

[0341] The basic formula for calculating natural frequency is as follows.

[0342] fn = (1 / 2π)*(Kn / Meff)^0.5

[0343] fn: n-th natural frequency (Hz)

[0344] kn: stiffness value of the n-th mode

[0345] Meff: effective mass (nacelle weight + tower mass + substructure mass + added mass in water)

[0346] To calculate the natural frequency, an example is shown below based on a cantilever beam.

[0347]

[0348] Based on the above data, an example of natural frequency calculation for the composite modular suction and fusion offshore wind foundation structure of the present invention is shown below.

[0349]

[0350] Therefore, as can be seen from the above, simply having high rigidity of the structure does not guarantee safety, and as stated above, the displacement, displacement angle, acceleration, and natural frequency of the net cell must be within the allowable values ​​to ensure the safety of the composite modular suction and fused offshore wind foundation structure of the present invention.

[0351] 4) Modular fabrication and ring connector technology divides the super-large structure into functional modules, fabricates them in parallel on land, and then manufactures the pontoons and stabilizers. Afterward, ring connectors are connected to the suction piles installed on top of the pontoons, and the substructure is installed on top to complete the super-large structure as functional modules, which are then assembled at sea. The ring connectors ensure the rigidity of the module joints and evenly distribute the load across multiple suction piles.

[0352] For example, the ring connector design transfers the load acting on the sub-tower to the suction piles; it must be designed to sufficiently resist this load. Below is an example of a ring connector design for a composite modular double suction and fused offshore wind foundation structure that reflects this.

[0353]

[0354]

[0356] The following is an example of a ring connector design for a composite modular triple suction and fused offshore wind foundation structure.

[0357]

[0359] 5) The precision launching and installation method minimizes underwater noise generated during the launching and installation process. Although the pump operation noise on the offshore barge is approximately 70 to 90 dB, it is not transmitted to the structure as it is connected to the suction piping. Since the underwater noise is approximately 30 to 50 dB or less (similar to the level of pump operation noise, lower than or similar to traffic noise), it is classified as a nearly noise-free construction method. It is also recognized as an eco-friendly method in the Environmental Impact Assessment (EIA), thereby minimizing adverse effects on the marine ecosystem. Furthermore, when using offshore cranes and barges, changes in the center of gravity (KG), center of buoyancy (KB), and metacenter height (GMT) are numerically predicted.

[0360] Among the composite modular suction and hybrid offshore wind foundation structures and launching methods, safety is examined when the composite modular suction and substructure is sunk to the seabed using a pontoon. As shown in Reference Table 1 below, when seawater is ballasted onto the pontoon and suction to gradually sink them, the safety GMT value is -3, which is unsafe. Therefore, a suspension load is applied using an offshore crane to make the GMT=3.3, allowing for safe sinking.

[0361] <Reference Table 1> Stability Analysis at Launch

[0362]

[0364] And reference Table 2 describes the process of removing the pontoon and setting the composite modular suction and substructure on the seabed while sinking. Since the suction is open and submerged, it is not affected by buoyancy, and the substructure is ballasted to slowly set it down to the seabed. In this case, the safety is also unstable as GMT=-2.0, so until it is set on the seabed, a marine crane is used to apply a suspension load to make GMT=2 so that it can be safely sunk.

[0365] <Reference Table 2> Stability Analysis at Final Setup

[0366]

[0368] When analyzing stability during launching in <Reference Table 1> and stability during final setting in <Reference Table 2> above, seawater must be filled inside the suction pile. In this case, since the lower part of the suction pile is open, a separate device must be installed. As shown in the attached Fig. 56, an air peg cone is fabricated and installed on the upper part of the pontoon, and an aramid fiber-reinforced polyurethane air peg is bonded inside the suction pile with a room-temperature curing adhesive to ensure there are no structural problems.

[0369]

[0371] Next, to remove the pontoon, the seawater inside the pontoon is deballasted while maintaining stability using the stabilizer of the sunken pontoon to gradually float it to the sea level. In this case, there is no problem even without using a separate marine crane because the GMT is 1 or higher.

[0373] <Reference Table 3: Analysis of Stability Upon Pontoon Withdrawal>

[0374]

[0376] The composite modular suction and substructure are placed on the seabed and penetrated 2 m into the seabed by their own weight. Then, work is performed up to the required penetration depth while performing precise placement and leveling of the structure through real-time monitoring based on the suction pump and sensors.

[0377] As a technology for long-term operation and environmental response, the scour prevention technology prevents scour by installing skirts on the exterior of ring connectors so that the connectors naturally function to prevent scour. It also maintains long-term integrity by applying a fatigue crack detection sensor network to module joints. During the initial installation phase, fiber optic sensors (FBGs), which are resistant to electromagnetic interference, are densely arranged along weld lines where stress is concentrated to monitor the strain distribution of the entire structure in real time. Simultaneously, acoustic emission (AE) sensors are placed on the inner and outer sides of the joints to capture elastic waves generated during the formation or progression of microcracks that are invisible to the naked eye, while smart wireless accelerometers are installed at key points of each module to indirectly monitor for stiffness degradation through changes in the structure's natural frequency. All sensors and communication cables are protected by titanium or specially coated stainless steel casings to withstand seawater corrosion, and power is supplied through energy harvesting technology utilizing micro-vibrations.

[0378] In the operation phase, collected strain and vibration data are synchronized with real-time marine environmental load information and compared with Von-Mises stress and fatigue life curves calculated in the design phase. Utilizing edge computing technology, an immediate alarm is transmitted when an abnormal signal exceeding a specific threshold occurs, and the accumulated actual measurement data is reflected in a digital twin model on land to serve as a predictive maintenance system that predicts fatigue life 5 to 10 years in the future. Through this, data-driven selective maintenance becomes possible without a large-scale full inspection during an operation period of over 25 years, thereby drastically reducing operating costs and maximizing structural reliability. An intelligent predictive maintenance-based offshore wind power structure health monitoring system is installed as shown in the attached Fig. 38. Effects of the invention

[0380] The present invention provides the following effects through the above-mentioned solution means.

[0381] 1. Changes in Design Paradigms Due to the Introduction of Ultra-Large Offshore Wind Turbines and Overcoming Limitations of Foundation Structures The primary challenge that this invention aims to solve is to overcome the structural design limitations resulting from the increasing size of turbines (10 MW to 20 MW class or higher), which is a rapid trend in the recent offshore wind industry. As turbine capacity increases, the self-weight of the superstructure, including the nacelle and blades, increases exponentially, and due to the rise in hub height, the overturning moment acting on the lower part of the tower has reached a level exceeding existing design standards. The existing monopile foundation method faces physical and economic barriers, such as the manufacturing cost of large-diameter steel pipes and the volume limitations of ultra-large pile driving equipment, as water depth increases and loads grow. The jacket method also suffers from chronic problems, such as the risk of fatigue failure in welded joints of complex truss structures and prolonged installation periods. Accordingly, the present invention completely overcomes the structural inefficiency of such conventional technology and provides a new dimension of foundation system capable of safely transferring the combined load of a super-large turbine (dynamic load caused by wind, waves, currents, earthquakes, and blade rotation) to the ground.

[0382] 2. Fundamental Elimination of Design Uncertainty through Direct Utilization of Ground Data In the conventional offshore foundation design process, ground parameters such as undrained shear strength (Su) and elastic modulus (E) were estimated through various empirical formulas and correlations based on limited sampling data obtained through boring. However, this indirect conversion process inevitably leads to design uncertainty, which causes an increase in construction costs by requiring the application of excessive safety factors to satisfy the strict tolerance and displacement angle limit conditions of super-large structures. To resolve this engineering inefficiency, the present invention establishes a technical system that directly projects the tip resistance (qc), sleeve friction (fs), pore water pressure (u2), and modified tip resistance (qt), which are actual data from the Pizocone Penetration Test (PCPT), onto the design algorithm without separate derivation parameter conversion (Direct Design Method). The core objective is to maximize the accuracy of bearing capacity calculations and prevent over-design by continuously identifying the layered structure and drainage characteristics of the ground and precisely simulating real-time ground responses.

[0383] 3. Solution to Structural Defects and Safety Issues of Conventional Suction Foundation Technology (GB 2615652A, etc.) The present invention addresses the critical structural and construction defects exposed by conventional suction foundation technology with similar objectives, particularly prior art such as the British GB 2615652A. First, the simple direct connection method between the upper part of the caisson and the connector body (box-shaped arm structure) found in conventional technology results in stress concentration due to the absence of reinforcement. This causes punching of the connection under repeated environmental loads, thereby increasing the risk of structural collapse. To solve this, the present invention secures structural integrity by developing a special ring connector technology that completely encloses the outer diameter of the suction pile and evenly distributes the load across multiple piles. Second, conventional technology attempts to secure self-weight by opening the top of the suction pile and filling it with rubble or sand; however, this not only causes sagging and structural deformation of the internal partition but also fails to provide a specific basis for weight design capable of responding to the powerful uplift force generated in actual super-large turbines. The present invention aims to completely resolve the problem of interference between blade rotation and natural frequency (Soft-Stiff Design) by implementing a weight and shape design that optimizes uplift resistance based on precisely calculated numerical analysis results.

[0384] 4. Securing feasibility for the offshore transportation and installation of super-heavy loads (4,000 to 5,000 ton class); The total weight of the substructure and suction caisson to support 0 MW to 20 MW class turbines approaches approximately 4,000 to 5,000 tons, which is a very harsh condition for fabricating it on land as a single structure or lifting it with existing offshore cranes. Many prior art technologies only present the theoretical feasibility of the construction method and lack specific solutions on how to actually fabricate such super-heavy loads, transport them to the sea, and install them. To solve this, the present invention introduces a functional modular fabrication method to overcome the constraints of onshore fabrication sites by dividing major components and fabricating them in parallel, thereby shortening the construction period and systematizing the process of precisely combining them at sea. In particular, it tracks real-time changes in the center of gravity (KG) and center of buoyancy (KB), which are the most dangerous factors during the launching and lowering processes, and secures suspension force control technology by mobilizing active buoyancy and marine cranes to prevent capsizing accidents in unstable sections where the metacenter height (GMT) decreases.

[0385] 5. Preservation of marine ecosystems and securing long-term operational stability (scour and fatigue failure); Conventional impact piling methods generate severe underwater noise and vibration, causing immense damage to the marine biosphere. This is a major cause of project delays resulting from environmental impact assessments and public complaints. This invention maximizes the value of eco-friendly construction by realizing noise- and vibration-free construction through the advancement of the suction penetration method utilizing the difference in internal and external water pressure. Furthermore, regarding the scour phenomenon occurring at the junction between the seabed and the structure, simple solutions proposed by conventional technology, such as rock berms or curtain systems, are vulnerable to settlement and long-term deformation problems in soft ground. This invention establishes a system that safely guarantees a design life of over 25 years by protecting the structure from corrosion and fatigue failure that may occur during long-term operation, as well as preventing scour through the design of an optimal penetration depth considering the strength characteristics of the ground and a load distribution system.

[0386] 6. Reduction of construction costs and maximization of economic feasibility (reduction of LCOE); Ultimately, to lower the Levelized Cost of Electricity (LCOE) of offshore wind power generation, the present invention minimizes the usage time of large equipment used throughout the entire process from the fabrication to the installation of foundation structures and numerically manages construction risks. The simplification of the assembly process using ring connectors, the prevention of trial and error through precision construction based on PCPT, and the shortening of construction time through modular methods enable a significant reduction in overall project costs, thereby providing a technical foundation to secure the economic feasibility of constructing ultra-large offshore wind farms.

[0387] 7. Utilizing predictive computing technology; it transmits immediate alerts when abnormal signals exceeding a specific threshold occur, and the accumulated actual measurement data is reflected in an onshore digital twin model to serve as a predictive maintenance system that predicts fatigue life 5 to 10 years in the future. Through this intelligent predictive maintenance-based offshore wind structure health monitoring system, data-driven selective maintenance becomes possible without large-scale full inspections during an operating period of over 25 years, thereby drastically reducing operating costs and maximizing the reliability of the structure. Brief explanation of the drawing

[0389] FIG. 1 is a perspective view of a composite modular triple suction, double suction, and fused offshore wind foundation structure according to an embodiment of the present invention. FIGS. 2, FIGS. 3, and FIGS. 29 are schematic diagrams showing a composite modular triple suction, double suction, and fused offshore wind foundation structure according to an embodiment of the present invention. FIGS. 4 and FIGS. 30 are drawings of a composite modular suction and fusion offshore wind foundation structure according to an embodiment of the present invention, in which a stabilizer is fabricated and installed on a pontoon installed on a skid shoe and skid rail for on-site installation. FIGS. 5, 6 and FIGS. 31, 32 are drawings of the steps of completing the fabrication of pontoons and stabilizers on skid shoes and skid rails for field installation of a composite modular suction and fused offshore wind foundation structure according to an embodiment of the present invention, finally placing the pontoons and stabilizers on a semi-submersible barge to float on the sea, conducting a sea trial, and then stacking the pontoons and stabilizers on land using the semi-submersible barge again. FIGS. 7 and FIGS. 33 are drawings showing the installation and welding of an air peg cone aligned with the suction pile position on the upper part of the completed pontoon and stabilizer according to an embodiment of the present invention. FIGS. 8 and FIGS. 34 are drawings of an aramid fiber-reinforced polyurethane air pack at the bottom of a suction pile and a module in which an aramid fiber-reinforced polyurethane air pack is completely attached to the inside of the bottom of the suction pile using a room temperature curing adhesive, among the composite modular suction and fused offshore wind foundation structures according to an embodiment of the present invention, and an air pack cone installed on the top of a pontoon. FIGS. 9 and FIGS. 35 are drawings of the step of installing a suction pile module on the upper part of a pontoon and installing a ring connector (a skirt for load transfer and scour prevention) over the suction pile among a composite modular suction and fused offshore wind foundation structure according to an embodiment of the present invention. FIGS. 10 and FIGS. 36 are drawings of the step of installing a sub-tower in the center of a ring connector while the ring connector (skirt for load transfer and scour prevention) is installed over the suction pile among the composite modular suction and fused offshore wind foundation structures according to an embodiment of the present invention. FIGS. 11 and 37 are drawings illustrating a process of completely sealing the air peg cone and suction pile of a pontoon by inflating an aramid fiber-reinforced polyurethane air peg using an air compressor to inject 46.03 bar of air pressure into the aramid fiber-reinforced polyurethane air peg in order to completely attach the air peg cone and suction pile after the composite modular suction and fusion offshore wind foundation structure pontoon according to an embodiment of the present invention is completely set up. FIGS. 12 and FIGS. 38 are drawings of a device that supplies power through energy harvesting technology utilizing a module joint fatigue crack detection sensor network according to an embodiment of the present invention, an array of fiber optic sensors (FBG), an acoustic emission (AE) sensor arrangement, a smart wireless accelerometer installation, and micro-vibrations, attached to a composite modular suction and fused offshore wind foundation structure. FIGS. 13 and FIGS. 39 are drawings of the process of loading a composite modular suction and fusion offshore wind foundation structure onto a semi-submersible barge using skid shoes and skid rails after completely setting it on a pontoon according to an embodiment of the present invention. FIGS. 14 and FIGS. 40 are drawings of the stage in which a composite modular suction and fusion offshore wind foundation structure according to an embodiment of the present invention is loaded onto a semi-submersible barge on a pontoon. FIGS. 15 and FIGS. 41 are drawings of the step of loading a composite modular suction and fusion offshore wind foundation structure onto a semi-submersible barge on a pontoon according to an embodiment of the present invention and transporting it to an installation site using a tugboat. FIGS. 16 and FIGS. 42 are drawings of the step of placing a composite modular suction and fusion offshore wind foundation structure on a pontoon according to an embodiment of the present invention onto a semi-submersible barge, and then slowly ballasting it onto the semi-submersible barge at the installation site to slowly sink it. FIGS. 17 and FIGS. 43 are drawings of the steps of placing a composite modular suction and fusion offshore wind foundation structure on a pontoon according to an embodiment of the present invention onto a semi-submersible barge, and slowly ballasting the semi-submersible barge at the installation site to slowly float the pontoon. FIGS. 18 and FIGS. 44 are drawings of the steps of placing a composite modular suction and fusion offshore wind foundation structure on a pontoon according to an embodiment of the present invention onto a semi-submersible barge, and then gradually ballasting the pontoon onto the semi-submersible barge at the installation site to fully float the pontoon on the semi-submersible barge. FIGS. 19 and FIGS. 45 are drawings of the steps of removing a composite modular suction and fusion offshore wind foundation structure on a pontoon according to an embodiment of the present invention from a semi-submersible barge and separating the semi-submersible barge and the pontoon using a tugboat. FIGS. 20 and FIGS. 46 are drawings of the steps in which, for safety purposes, a marine crane is mobilized to install a stability load-bearing device on a pontoon separated from a composite modular suction and fusion offshore wind foundation structure and a semi-submersible barge on a pontoon according to an embodiment of the present invention, and the pontoon is slowly ballasted and sunk, while the suction piles are in close contact with the air peg cones and are also ballasted on the suction piles and slowly sunk to the seabed. FIGS. 21 and FIGS. 47 are side views of the step in which a marine crane is mobilized to install a stability load-bearing device for safety on a composite modular suction and fusion offshore wind foundation structure on a separated pontoon according to an embodiment of the present invention, and the pontoon is slowly ballasted and sunk, while the suction pile is attached to the air peg cone and ballasted on the suction pile as well and slowly sunk to the seabed. FIGS. 22 and FIGS. 48 are drawings of the step of opening a compressor air valve to remove the pressure applied to the aramid fiber-reinforced polyurethane air pack in order to separate the composite modular suction and fusion offshore wind foundation structure on the pontoon from the pontoon at a position for separating the pontoon according to an embodiment of the present invention. FIGS. 23 and FIGS. 49 are drawings of the step of completely separating the pontoon and the composite modular suction and fusion offshore wind foundation structure using a tugboat by opening the compressor air valve according to an embodiment of the present invention to remove the pressure applied to the aramid fiber-reinforced polyurethane air pack. FIGS. 24 and FIGS. 50 are drawings of the steps of placing a composite modular suction and fusion offshore wind foundation structure according to an embodiment of the present invention on the seabed, penetrating it by its own weight, and then using a suction hose, suction manifold, and suction pump to suck up the soil inside the suction pile and send it to a temporary soil storage area. FIGS. 25 and FIGS. 51 are drawings of the steps in which, according to an embodiment of the present invention, the suction pile and ring connector of a composite modular suction and fused offshore wind foundation structure suck up soil from within the suction pile using a suction hose, suction manifold, and suction pump until the skirt penetrates into the seabed, send it to a temporary soil storage area, and then discharge the sucked-up soil to the seabed through a soil discharge pipe. FIGS. 26 and FIGS. 52 are drawings of the step of filling the interior of a sub-tower using marine ready-mix concrete to fill the interior of the sub-tower to the required height in order to remove the tensile load of the suction pile and ring connector of a composite modular suction and fused offshore wind foundation structure according to an embodiment of the present invention, after the skirt has been fully penetrated into the seabed ground. FIGS. 27 and FIGS. 53 are drawings of the step of installing a post tower using a marine crane and a post tower installation device after the completion of the installation of a composite modular suction and fused offshore wind foundation structure according to an embodiment of the present invention. FIGS. 28 and FIGS. 54 are drawings of the steps of installing a composite modular suction and fusion offshore wind foundation structure and a post tower according to an embodiment of the present invention using an offshore crane and a turbine and blade installation device after the completion of the installation. FIG. 55 is a drawing of the detailed description of the ring connector (skirt for load transfer and scour prevention) in the composite modular suction and fused offshore wind foundation structure according to an embodiment of the present invention, the location of the grid beam installed on the suction pile, the grid beam installed on the bottom of the sub-tower, the suction hose, the air vent pipe, the compressor hose, and the automatic valve (open, close), and the step of installing a work platform for installing the post tower and turbine. FIG. 56 is a drawing of the steps of fixing a composite modular suction and fusion offshore wind foundation structure according to an embodiment of the present invention onto a pontoon, installing an aramid fiber-reinforced polyurethane air pack at the bottom of the suction pile to seal the suction pile and the air pack cone of the pontoon for ballasting the suction pile, attaching the air pack with a room-temperature curing adhesive to bond the air pack inside the suction pile, inserting the suction pile into the air pack cone on the pontoon, and injecting air into the air pack using a compressor at a pressure of 46.03 bar to ensure perfect watertightness by making it close to the air pack cone. FIG. 57 shows the construction of an intelligent suction pile penetration control system algorithm based on PCPT actual data in the intelligent suction pile penetration process, which follows the sequence of actual ground data → resistance prediction → real-time comparison → automatic pressure correction during the construction phase of a composite modular suction and fused offshore wind foundation structure according to an embodiment of the present invention. Specific details for implementing the invention

[0390] The present invention is capable of various modifications and may have various embodiments; specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and it should be understood that it includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the present invention. In describing the present invention, detailed descriptions of related prior art are omitted if it is determined that such detailed descriptions may obscure the essence of the present invention.

[0392] FIGS. 2, 3, and 29 are perspective views showing a composite modular triple (double) suction and fused offshore wind foundation structure according to an embodiment of the present invention. The structure comprises a suction pile (11), a suction pile local buckling prevention stiffener (10) for preventing local buckling of the suction pile, a ring connector (skirt for load transfer and scour prevention) (9) connected to the upper part of the suction pile, a sub-tower (6) in the center of the ring connector (skirt for load transfer and scour prevention), a sub-tower local buckling prevention stiffener (7) inside the sub-tower, and a post tower (3) to be connected to the sub-tower. A post tower installation stabing cone (5) is connected to the lower part of the post tower to ensure proper insertion when installed with the post tower local buckling prevention stiffener (4) and the sub-tower. A turbine (2) is installed on the upper part of the post tower, and a turbine blade (1) is mounted on the front of the turbine. This is referred to as a composite modular suction and fused offshore wind foundation structure in the present invention. does.

[0393] FIGS. 4 and FIGS. 30 describe a process of manufacturing a pontoon (12) on land according to the above embodiment, installing a pontoon bulkhead (67), a pontoon ballasting (ON, OFF) valve (65), and a pontoon ballasting pipe (64) for rigidity and ballasting tanks, installing a pontoon (12) on a skid shoe (14) and a skid rail (15) for on-site installation of a composite modular suction and fusion offshore wind foundation structure, installing a stabilizer bulkhead (66) to manufacture a stabilizer (13) to create rigidity and ballasting tanks, manufacturing a stabilizer ballasting pipe (62) and a stabilizer ballasting (ON, OFF) valve (63), and lifting the stabilizer (13) using a land crane (16) and a lifting device (17) to install it on the pontoon (12).

[0394] FIGS. 5, FIGS. 6 and FIGS. 31, FIGS. 32 are configured such that, in accordance with the above embodiment, a skid rail (15) is placed on land, a pontoon (12) is placed on a skid shoe (14) on the skid rail (15), a stabilizer (13) is welded to the pontoon (12), and a pontoon ballasting pipe (64) located on the stabilizer (13) and the pontoon (12) is connected, and finally, a ballasting compressor is installed on the upper horizontal stabilizer bulkhead (66) of the stabilizer (13), i.e., on the bulkhead, and finally, the pontoon (12) and stabilizer (13) are placed on a semi-submersible barge (23) to float on the sea, and after a sea trial, the pontoon (12) and stabilizer (13) are stacked on land using the semi-submersible barge (23).

[0395] FIGS. 7 and FIGS. 33 describe the steps of placing the pontoon (12) and stabilizer (13) on the land skid rail (15) and skid shoe (14) again after the sea trial according to the above embodiment, and installing and welding an air peg cone (18) on the pontoon (12) using a lifting device (17) and a land crane (16) in alignment with the suction pile (11) on the pontoon (12).

[0396] FIGS. 8 and FIGS. 34 describe the step of installing a suction pile local buckling prevention stiffener (10) inside a suction pile (11) by manufacturing and welding it at a location where an air peg cone (18) is welded to the upper part of the pontoon (12) according to the above embodiment, and also installing a module in which an aramid fiber reinforced polyurethane air peg (19) is completely attached to the lower part of the suction pile (11) using a room temperature curing adhesive (20), by inserting the suction pile (11) into the air peg cone (18) installed on the upper part of the pontoon (12) using a lifting device (17) and a land crane (16).

[0397] FIG. 57 includes the step of fixing the composite modular suction and fusion offshore wind foundation structure according to the above embodiment onto the pontoon (12), installing an aramid fiber-reinforced polyurethane air peg (19) at the bottom of the suction pile to seal the suction pile (11) and the air peg cone (18) of the pontoon (12) for ballasting the suction pile (11), attaching the air peg with a room temperature curing adhesive (20) to bond it inside the suction pile (11), and then inserting the suction pile (11) into the air peg cone (18) on the pontoon (12) and injecting air into the aramid fiber-reinforced polyurethane air peg (19) using a compressor hose (22) at a pressure of 46.03 bar to ensure a tight seal with the air peg cone (18) and perfect watertightness.

[0398] FIGS. 9 and FIGS. 35 illustrate the steps of installing a suction pile (11) module on the upper part of the pontoon (12) in the air peg cone (18) on the upper part of the pontoon (12) according to the above embodiment, and then installing and welding a ring connector (load transfer and scour prevention skirt) (9) on top of it using a lifting device (17) and a land crane (16) after welding to secure sufficient rigidity of the ring connector (load transfer and scour prevention skirt) (9).

[0399] FIGS. 10 and FIGS. 36 describe the step of welding and installing a ring connector (load transfer and scour prevention skirt) (9) (9) over a suction pile (11) in accordance with the above embodiment, and then completing the fabrication of a sub-tower local buckling prevention stiffener (7) inside the sub-tower (6) and welding it to the center of the ring connector (load transfer and scour prevention skirt) (9).

[0400] FIG. 55 shows a suction pile local buckling prevention stiffener (10) for preventing local buckling caused by the suction pressure of the suction pile (11) and external earth pressure, wherein a scour prevention skirt (57) is attached to a ring connector (load transfer and scour prevention skirt) (9) according to the above embodiment to prevent scour near the suction pile (11) when it is inserted into the ground, and a grid beam (51) installed on the suction pile (11) to prevent local buckling caused by the suction pressure of the suction pile (11) and external earth pressure when the suction pile (11) is inserted into the ground and the ground is sucked through the suction hose (31) of the suction pump (30), thereby generating pressure on the upper part of the suction pile (11); concrete is poured to reduce the upward load during operation on the sub-tower (6), and a grid beam (52) installed on the bottom of the sub-tower so that the upper deck of the ring connector (load transfer and scour prevention skirt) (9) can withstand the weight of the concrete, and a sub-tower local to prevent local buckling of the sub-tower (6). A buckling prevention stiffener (7), a suction hose (31), a concrete hose (36) for pouring concrete into the sub-tower (6), an air vent pipe (52), a compressor hose (22), and an automatic valve (open, close) (54) are installed, and a work platform (59) for installing the post tower (3) and turbine (2) is installed. In order to sink the composite modular suction and fused offshore wind foundation structure of the present invention into seawater, a certain amount of seawater must be ballasted to the suction pile (11) and sub-tower (6). To this end, a suction pile and sub-tower ballasting system (8) is installed. In particular, the ring connector (skirt for load transfer and scour prevention) (9) must have sufficient rigidity to transfer the 6-directional load of the sub-tower (6) to the suction pile (11), so a bulb flat (56), a 35 mm horizontal bulkhead (55), and a 5-way 35 mm vertical bulkhead (58) are installed. It includes installing it to ensure sufficient rigidity.

[0401] FIGS. 11 and FIGS. 37 describe a process step in which, after being completely set up on the pontoon (12) according to the above embodiment, an air compressor (21) is used to inflate the aramid fiber-reinforced polyurethane air peg (19) through a compressor hose (22) to inject 46.03 bar of air pressure into the aramid fiber-reinforced polyurethane air peg (19) in order to completely attach the air peg cone (18) and the suction pile (11), thereby completely sealing the air peg cone (18) and the suction pile (11) of the pontoon (12).

[0402] FIGS. 12 and FIGS. 38 apply a fatigue crack detection sensor network for module joints according to an embodiment of the present invention to maintain long-term soundness. First, during the installation phase, optical fiber sensors (FBG) (71) resistant to electromagnetic interference are densely arranged along the weld line where stress is concentrated to determine the strain distribution of the entire structure in real time. At the same time, acoustic emission (AE) sensors (72) are placed on the inner and outer sides of the joint to capture elastic waves generated when micro-cracks that cannot be confirmed with the naked eye are created or progressed. Additionally, smart wireless accelerometers (73) are installed at key points of each module to indirectly monitor whether stiffness is degraded through changes in the natural frequency of the structure. All sensors and communication cables are protected by titanium or specially coated stainless steel casings (75) to prevent seawater corrosion, and are powered by energy harvesting device technology (74) utilizing micro-vibrations, etc., and these devices are attached to composite modular suction and fusion offshore wind foundation structures, and these devices are attached to the surface of fiber optic sensors (FBG sensors) (71) or embedded, specifically using epoxy-based adhesive (e.g., Epoxy Resin Adhesive) on the surface of the structure, and cables are protected by protective metal clips / welded fixing if necessary, and acoustic emission sensors (AE sensors) (72) are attached to the surface contact, using epoxy adhesive or silicone-based adhesive on the surface of the structure, and a coupling agent (grease, gel) is applied between the sensors and the structure to improve signal transmission efficiency, and smart wireless accelerometer sensors (73) are fixed by bolt fastening or clamping, and bolt fastening brackets are installed on key parts of the structure (top of the tower, blade, etc.) and auxiliary fixing with epoxy adhesive if necessary. The energy harvesting power module (74) must be welded or bolted and fixed or bolted to the internal frame of the structure and installed in close contact with the structure for the utilization of vibration / wave energy.The corrosion-resistant casing (75) is used to protect the lines of all sensors, and is configured by welding or bolting, and then welding or bolting it to the internal frame of the structure.

[0403] FIGS. 13 and 39 illustrate a step of loading a semi-submersible barge (23) by ballasting the semi-submersible barge (23) to level it during the process of loading a composite modular suction and fusion offshore wind foundation structure on a pontoon (12) according to an embodiment of the present invention onto a pontoon (12) and a stabilizer (13) in front of a quay wall (24), and then loading it onto a semi-submersible barge (23) using a skid shoe (14) on a skid rail (15).

[0404] FIGS. 14 and FIGS. 40 illustrate the step of completing the loading of a composite modular suction and fusion offshore wind foundation structure onto a semi-submersible barge (23) on a pontoon (12) according to an embodiment of the present invention.

[0405] FIGS. 15 and FIGS. 41 illustrate the configuration of the step of transporting a composite modular suction and fusion offshore wind foundation structure on a pontoon (12) according to an embodiment of the present invention to an installation site by loading it onto a semi-submersible barge (23) and connecting two strands of a towing wire rope (43) to a link plate (44), connecting the link plate (44) to the towing wire rope (43), and connecting the towing wire rope (43) to a tugboat (25) to transport it to the installation site.

[0406] FIGS. 16 and FIGS. 42 illustrate the configuration of the steps of placing a composite modular suction and fusion offshore wind foundation structure on a semi-submersible barge (23) on a pontoon (12) and stabilizer (13) according to an embodiment of the present invention, arriving at the installation site, and then ballasting the semi-submersible barge (23) to gradually sink.

[0407] FIGS. 17 and FIGS. 43 are configured such that a composite modular suction and fusion offshore wind foundation structure is placed on a semi-submersible barge (23) on top of a pontoon (12) and a stabilizer (13) according to an embodiment of the present invention, and the semi-submersible barge (23) is slowly ballasted at the installation site to slowly sink the semi-submersible barge (23), and when the semi-submersible barge (23) has sunk 5.3m from the top, the pontoon (12) and the stabilizer (13) are on the verge of floating together with the composite modular suction and fusion offshore wind foundation structure, so ballasting must be done very carefully to slowly sink it.

[0408] FIGS. 18 and FIGS. 44 illustrate a configuration of a step in which a composite modular suction and fusion offshore wind foundation structure is placed on a semi-submersible barge (23) on top of a pontoon (12) and a stabilizer (13) according to an embodiment of the present invention, and the semi-submersible barge (23) is slowly ballasted at the installation site to slowly sink the semi-submersible barge (23), and when the semi-submersible barge (23) sinks carefully from 5.3m from the top to finally 7m, the pontoon (12) and the stabilizer (13) are floated together with the composite modular suction and fusion offshore wind foundation structure.

[0409] FIGS. 19 and FIGS. 45 illustrate the configuration of the step of completely removing a composite modular suction and fusion offshore wind foundation structure on a pontoon (12) and a stabilizer (13) according to an embodiment of the present invention from a semi-submersible barge (23), and then completely separating the semi-submersible barge (23), the pontoon (12), and the stabilizer (13) by connecting a towing wire rope (43) to a tugboat (25) and using the tugboat (25).

[0410] FIGS. 20 and 46 illustrate a composite modular suction and fusion offshore wind foundation structure and a semi-submersible barge (23) separated from the pontoon (12) and stabilizer (13) according to the above embodiment. For safety during sinking, a marine crane stability adjustment (26) and a stability load device (27) are mobilized to apply a load during stability, thereby ensuring safety. The pontoon (12) and stabilizer (13) are gradually sunk by ballasting them into partitioned tanks of the pontoon bulkhead (67) and stabilizer bulkhead (66) using a ballasting compressor (61), passing through the stabilizer ballasting pipe (62) and pontoon ballasting pipe (64), and using a stabilizer ballasting (ON, OFF) valve (63) and a pontoon ballasting (ON, OFF) valve (65). Meanwhile, the suction pile (11) The structure is configured to be in close contact with the air pack cone (18), ballasted using the suction pile and sub-tower ballasting system (8) on the suction pile (11), and slowly sunk to the seabed.

[0411] FIGS. 21 and 47 illustrate a composite modular suction and fusion offshore wind foundation structure and a semi-submersible barge (23) separated from the pontoon (12) and stabilizer (13) according to the above embodiment. For safety during sinking, a marine crane stability adjustment (26) and a stability load device (27) are mobilized to apply a load during stability, thereby ensuring safety. The pontoon (12) and stabilizer (13) are gradually sunk by ballasting them into partitioned tanks of the pontoon bulkhead (67) and stabilizer bulkhead (66) using a ballasting compressor (61), passing through the stabilizer ballasting pipe (62) and pontoon ballasting pipe (64), and using a stabilizer ballasting (ON, OFF) valve (63) and a pontoon ballasting (ON, OFF) valve (65). Meanwhile, the suction pile (11) The structure is configured to be in close contact with the air pack cone (18), ballasted using the suction pile and sub-tower ballasting system (8) on the suction pile (11), and slowly sunk to the seabed.

[0412] FIGS. 22 and 48 illustrate, in accordance with the above embodiment, a composite modular suction and fusion offshore wind foundation structure is separated from the pontoon (12) and stabilizer (13) at a position for separating the pontoon (12) and stabilizer (13) by opening the compressor air valve (28) so that the pressure applied to the aramid fiber-reinforced polyurethane air pack (19) is completely removed through the compressor hose (22), and at the same time, the pontoon (12) and stabilizer (13) are slowly inclined ballasted / deballasted using the compressor (61) through the stabilizer ballasting pipe (62) and pontoon ballasting pipe (64) and the stabilizer ballasting (ON, OFF) valve (63) and pontoon deballasting (ON, OFF) valve (65) to the partitioned tanks of the pontoon bulkhead (67) and stabilizer bulkhead (66). The configuration of the step of separating the pontoon (12), stabilizer (13) and composite modular suction and fusion offshore wind foundation structure while sinking by ballasting / deballasting.

[0413] FIGS. 23 and 49 completely separate the pontoon (12), stabilizer (13), and composite modular suction and fused offshore wind foundation structure according to the above embodiment, and use a marine crane stability adjustment (26) and a stability loading device (27) to maintain stability, and with the interior of the suction pile (11) completely submerged, deballasting of the ballasting seawater from the sub-tower is performed again using a partial suction pile and sub-tower ballasting system (8), and the pontoon (12) and stabilizer (13) are completely separated by connecting them to a tugboat (25) using a towing wire rope (43), and the pontoon (12) and stabilizer (13) are ballasted using a ballasting compressor (61) through the stabilizer ballasting pipe (62) and pontoon ballasting pipe (64) to the stabilizer ballasting (ON, OFF) valve (63) and pontoon ballasting (ON, OFF). The configuration is a step of moving the pontoon (12) to the land quay (24) by leveling it using the partitioned tanks of the pontoon bulkhead (67) and stabilizer bulkhead (66) with the valve (65) so that the pontoon (12) comes out to the sea surface.

[0414] FIGS. 24 and 50 illustrate the steps of an eco-friendly installation method in which, according to the above embodiment, a composite modular suction and fused offshore wind foundation structure is placed on the seabed and penetrated by its own weight using an offshore crane stability adjustment (26) and a stability load device (27), and then the suction hose (31) and automatic valve (open, closed) (54) are opened, and the soil inside the suction pile (11) is sucked in using a suction manifold (29) and a suction pump (30) installed on the offshore crane (33) and sent to a temporary soil storage (32), and then the soil is discharged to the seabed ground through a soil discharge pipe (34) to prevent pollution.

[0415] FIGS. 25 and FIGS. 51 illustrate the steps of an eco-friendly installation method in which, according to the above embodiment, the suction pile (11) and ring connector (skirt for load transfer and scour prevention) (9) of a composite modular suction and fused offshore wind foundation structure are driven into the seabed, and the suction hose (31) and automatic valve (open, closed) (54) are opened until the scour prevention skirt (57) is completely driven into the seabed, and the soil inside the suction pile (11) is sucked in using the suction manifold (29) and suction pump (30) installed on the offshore crane (33) and sent to a temporary soil storage (32), and then the soil is discharged into the seabed through the soil discharge pipe (34) to prevent pollution.

[0416] FIGS. 26 and FIGS. 52 are configured as steps of filling the interior of a sub-tower (6) using a marine ready-mix concrete (37) on top of a marine crane (33) through a concrete hose (36) to fill the interior of the sub-tower (6) to the required height to remove the tensile load of the suction pile (6) according to the above embodiment, and to complete the skirt penetration of the suction pile (11) and ring connector (skirt for load transfer and scour prevention) (9) into the seabed ground.

[0417] FIGS. 27 and FIGS. 53 are the configuration of the post tower (3) installation work stage, in which, after the installation of the composite modular suction and fusion offshore wind foundation structure according to the above embodiment is completed, a post tower local buckling prevention stiffener (4) and a post tower installation stabing cone (5) are manufactured in advance at the factory and loaded onto a marine crane (33), then at the installation site, the post tower installation stabing cone (5) is inserted into the upper part of the previously installed sub-tower (6) using the marine crane post tower installation (39) and the post tower installation device (40), and welding and welding inspection are completed in the work material (59).

[0418] FIGS. 28 and FIGS. 54 are configured for the steps of completing the installation of a post tower (3) after the installation of a composite modular suction and fusion offshore wind foundation structure according to the above embodiment, loading a turbine (2) and a turbine blade (1) onto an offshore crane (33), and then, at the installation site, using an offshore crane turbine and blade installation device (42), inserting a tower installation stabbing cone (5) into the top of the previously installed post tower (3), and completing welding and welding inspection in the work material (59) to complete the installation of the turbine (2) and the turbine blade (1).

[0419] FIG. 57 is an algorithm flowchart illustrating the intelligent suction pile penetration control system based on actual PCPT data, which is the core technology of the present invention. The present invention provides an intelligent construction mechanism that overcomes ground uncertainty through real-time data feedback. First, the system begins by inputting actual measurement parameters, such as cone resistance (qc), sleeve friction (fs), and pore water pressure (u2), obtained through the Pizocone Penetration Test (PCPT) in the construction area. The control unit precisely analyzes these data in micro-depth units to numerically calculate in advance the underground resistance expected to occur at each depth in which the suction pile is penetrated. This enables precise penetration design based on the actual physical values ​​of the ground, moving away from the conventional method that relied on simple theoretical estimation or the operator's experience. Subsequently, when the actual penetration of the suction pile shown in FIG. 24 to 25 and FIG. 50 to 51 begins, the system continuously measures the actual penetration depth of the pile and changes in internal negative pressure and pore water pressure (u2) through real-time sensing. At this time, the central control unit immediately compares and analyzes the previously calculated resistance prediction data by depth with the actual data measured in real time at the site. If the actual penetration depth falls short of the target value or if there are signs that the horizontal alignment of the structure is deviating due to ground heterogeneity, the system re-references the qc value at the point to recalculate the optimal negative pressure to overcome the resistance and automatically feedback-corrects the output of the suction pump to perform penetration while maintaining precise horizontal alignment. At the same time, by monitoring the real-time changing pore water pressure (u2) data to diagnose the state of excess pore water pressure inside the ground, it detects in advance any heaving or piping phenomena that may occur during suction. These actual measurement data act as safety thresholds within the control algorithm to prevent ground failure and guide the ultra-large offshore wind foundation structure to be installed while maintaining optimal speed and precise horizontal alignment.Finally, when the pile reaches the target design depth, the system saves the entire construction data and establishes an intelligent suction pile penetration control system algorithm based on actual PCPT data, which is an intelligent penetration process (100), thereby completing the installation of a stable foundation structure.

[0421] Although the present invention has been described in detail with respect to specific embodiments described above, it is obvious to those skilled in the art that various modifications and variations are possible within the scope of the technical spirit of the invention, and it is natural that such modifications and variations fall within the scope of the appended claims. Explanation of the symbols

[0423] 1 : Turbine blade 34 : Soil discharge pipe 2 : Turbine 35 : Concrete filling (reduction of pull-out load) 3 : Post Tower 36 : Concrete Hose 4: Post tower local buckling prevention stiffener 37: Marine ready-mix concrete 5: Stabbing cone for post tower installation 38: Concrete hose lifting device 6 : Sub-tower 39 : Installation of marine crane post tower 7: Sub-tower local buckling prevention stiffener 40: Post-tower installation device 8: Suction pile and sub-tower ballasting system 41: Installation of Offshore Crane Turbines and Blades 9: Ring connector (skirt for load transfer and scour prevention) 42: Turbine and Blade Installation Device 10: Suction pile local buckling prevention stiffener 43: Towing wire rope 11 : Suction file 44 : Link plate 12 : Pontoon 51 : Grid beam installed on suction piles 13: Stabilizer 52: Grid beam installed on the sub-tower floor 14 : Skid shoe 53 : Air vent piping 15 : Skid rail 54 : Automatic valve (open / close) 16 : Land crane 55 : 35 mm horizontal bulkhead 17 : Lifting device 56 : Bulb flat 18 : Airpack Cone 57 : Anti-isolation skirt 19 : Aramid Fiber Reinforced Polyurethane Air Peck 58:5-Ways 35 mm longitudinal bulkhead 20: Room temperature curing adhesive 59: Workbench 21 : Compressor (46.03 bar) 61 : Ballasting Compressor 22: Compressor hose 62: Stabilizer ballasting piping 23 : Semi-submersible barge 63 : Stabilizer ballasting (ON,OFF) valve 24 : Quay Wall 64 : Pontoon Ballasting Piping 25 : Tugboat 65 : Pontoon Ballasting (ON, OFF) Valve 26: Offshore crane stability adjustment 66: Stabilizer bulkhead 27 : Stability Loading Device 67 : Pontoon Bulkhead 28 : Compressor air valve open 71 : Fiber optic sensor (FBG sensor) 29 : Suction Manifold 72 : Acoustic Emission Sense (AE Sense) 30 : Suction pump 73 : Smart wireless accelerometer 31: Suction hose 74: Energy harvesting power module 32 : Temporary soil storage tank 75 : Anti-corrosion casing 33 : Offshore crane 100 : Construction of an Intelligent Suction Pile Penetration Control System Algorithm Based on PCPT Actual Measurement Data

Claims

Claim 1 A composite modular suction pile and fused offshore wind foundation structure system forming a foundation structure supporting an offshore wind turbine, comprising: a plurality of suction piles (11) that are driven into the seabed; a ring connector (9) coupled to the upper portion of the plurality of suction piles (11) and generating buoyancy through its internal hollow shape, and performing load transfer and scour prevention functions; a connecting frame that connects the plurality of ring connectors (9) to distribute the upper load; a sub-tower (6) provided on the upper portion of the connecting frame or ring connector (9) to support a post tower (3); a suction pump (30) module that generates a penetration force by individually discharging seawater inside the suction piles (11); and an intelligent penetration processor that controls the operation of the suction pump module in real time in conjunction with actual ground measurement data at the site and establishes an intelligent suction pile (11) penetration control system algorithm (100) based on PCPT actual measurement data. The intelligent suction pile penetration control system algorithm (100) based on the above PCPT actual measurement data includes: a) a real-time ground resistance analysis step receives values ​​of cone resistance (qc), sleeve friction (fs), and pore water pressure (u2) obtained from a previously performed piezocone penetration test (PCPT), and calculates variable penetration resistance force in real time according to the layered structure of the ground at each penetration location; b) a penetration path and pressure calculation step determines the target penetration depth and step-by-step negative pressure of each suction pile (11) based on the calculated ground resistance force; and c) an active negative pressure correction and horizontality control step compares the real-time penetration depth and internal pressure measured during penetration with the target value, and automatically corrects the horizontality of the foundation structure by individually controlling the pump output for each suction pile when tilting occurs due to ground heterogeneity, and controls the penetration speed within a critical range for preventing ground heaving by referring to the u2 value. A composite modular suction pile and fused offshore wind foundation structural system characterized by Claim 2 A composite modular suction pile and fused offshore wind foundation structure system according to claim 1, comprising the steps of: loading the foundation structure onto a semi-submersible barge (23) and transporting it to an installation area; injecting or discharging fluid into or out of the buoyancy bodies (11 and 6) provided in the foundation structure to control buoyancy; and controlling the buoyancy of the suspension load device (27) of the offshore crane and the buoyancy bodies (11 and 6) in conjunction to maintain the metacenter height (GMT) of the entire structure at a positive (+) value and sinking it underwater. Claim 3 A composite modular suction pile and fused offshore wind foundation structure system according to claim 2, comprising an air peg cone (18) of a pressure sealing unit provided to seal the lower opening of the suction pile (11), wherein the pressure sealing unit comprises an aramid fiber reinforced polyurethane air peg (19), which is an expansion member of a flexible material, to block the inflow of external seawater through internal pressure regulation and provide a cushioning force during descent. Claim 4 A composite modular suction pile and fused offshore wind foundation structure system according to claim 1, wherein a ring-shaped connector (9) for blocking load concentration is provided at the joint portion of the upper part of the suction pile (11), and the connector (9) forms a foundation structure with an internal structure in which a plurality of stiffeners (51, 52, 55, 56, 57, 58) are arranged radially. Claim 5 A composite modular suction pile and fused offshore wind foundation structure system that forms a foundation structure, wherein a plurality of skirts or protruding anti-scouring skirts (57) are formed on the outer surface of the upper part of the suction pile (11) or the connection part of the ring connector (9) to prevent scouring caused by seabed flow. Claim 6 A composite modular suction pile and fused offshore wind foundation structure system forming a foundation structure, further comprising: a plurality of sensor units (71, 72, 73, 74, 75) attached to the foundation structure member to detect strain, vibration, and acoustic signals; and a control unit that analyzes data received from the sensor units to determine in real time whether there is a structural defect. Claim 7 In a composite modular suction pile and fused offshore wind foundation structural system forming a foundation structure supporting an offshore wind turbine, the system comprises: a suction pile (11) equipped with a suction pile local buckling prevention stiffener (10) inside to prevent local buckling; a ring connector (9) welded to the upper end of the suction pile (11) to distribute loads transmitted from above and to prevent scouring of the seabed through a skirt provided on the outer surface; a sub-tower (6) vertically extended and installed on the upper central side of the ring connector (9) and equipped with a sub-tower local buckling prevention stiffener (7) inside; and a post tower (3) inserted and coupled to the upper end of the sub-tower (6), including a post tower local buckling prevention stiffener (4) inside, and having a conical post tower installation stabbing cone (5) integrally formed at the lower end to support a precise insertion guide into the sub-tower (6). A composite modular suction pile and fused offshore wind foundation structure system comprising: a turbine (2) placed on top of the post tower (3) and a turbine blade (1) rotatably mounted on the front of the turbine; and, in order to install a composite modular foundation structure in the sea in which the suction pile (11), ring connector (9), sub-tower (6), and post tower (3) are interconnected, a foundation structure is placed on top of a pontoon (12) and a stabilizer (13) in which a grid beam (51) and a ballasting tank are partitioned inside; the foundation structure is sunk to the seabed while maintaining the metacenter height (GMT) at a positive (+) value through ballasting that fills the inside of the pontoon (12) with seawater and suspension load control using an offshore crane (33); and after the suction pile (11) contacts the seabed, a suction pressure is generated to discharge the internal seawater to the outside, thereby penetrating and settling it to the required depth. Claim 8 In claim 7, the pontoon (12) has a grid-structured pontoon bulkhead (67) installed as a partition inside to secure structural rigidity and is equipped with a plurality of independent ballasting tanks, each tank being equipped with a pontoon ballasting pipe (64) and a pontoon ballasting valve (65) for controlling the inflow and outflow of fluid; the stabilizer (13) is equipped with a stabilizer bulkhead (66) for internal rigidity reinforcement and independent ballasting, and is configured to include a stabilizer ballasting pipe (62) and a stabilizer ballasting valve (63) for individual flow rate control by an external control signal; A composite modular suction pile and fused offshore wind foundation structure system characterized by preparing for the installation of the above stabilizer (13) by lifting the above stabilizer (13) using a land crane (16), integrating it by joining it to a designated location on the upper part of the above pontoon (12), placing the pontoon (12) with the stabilizer (13) joined thereto on a skid rail (15), and horizontally moving and mounting a composite modular foundation structure onto the above pontoon (12) via a skid shoe (14). Claim 9 In claim 8, for the land assembly and sea test of the floating body for launching the above-mentioned foundation structure, the pontoon (12) is placed on the upper part of the skid shoe (14) positioned on the upper part of the land skid rail (15), the stabilizer (13) is welded and integrated to the upper surface of the pontoon (12), the ballasting pipe of the stabilizer (13) and the pontoon ballasting pipe (64) of the pontoon (12) are interconnected to form an integrated ballasting line, a ballasting compressor that supplies air pressure for ballasting is installed on the upper surface of the stabilizer bulkhead (66) installed horizontally inside the stabilizer (13), the pontoon (12) combined with the stabilizer (13) is loaded onto a semi-submersible barge (23) and moved to the sea, the semi-submersible barge (23) is submerged to float the pontoon (12) and the stabilizer (13) on the sea, and the stability and ballasting functions in the floating state A composite modular suction pile and fused offshore wind foundation structure system characterized by performing a sea trial for inspection and using the semi-submersible barge (23) to lift the pontoon (12) and stabilizer (13) back up and move them to land for stacking. Claim 10 In claim 9, the assembly of the pontoon (12) and stabilizer (13) in which the sea trial has been completed is re-positioned on the upper surface of the land skid rail (15) and skid shoe (14), and an air-pack cone (18) that supports cushioning and leveling through internal air pressure control is installed corresponding to the point on the upper surface of the pontoon (12) where the suction pile (11) is to be placed; the installation of the air-pack cone (18) is characterized by manufacturing a cone-shaped air-pack cone (18) body by rolling a steel plate, lifting and moving the manufactured air-pack cone (18) using a land crane (16) and a lifting device (17), and welding and fixing the air-pack cone (18) at a designated location on the upper surface of the pontoon (12). Claim 11 In claim 10, to form the main body of the suction pile (11), an outer wall is fabricated by rolling a steel plate; a suction pile local buckling prevention stiffener (10) is fabricated and welded to the inner surface of the fabricated suction pile (11) to prevent local buckling caused by design load and water pressure; to maintain airtightness and mitigate shock between the lower end of the suction pile (11) and the air peg cone (18) on the upper part of the pontoon (12), an aramid fiber-reinforced polyurethane air peg (19) is attached to the lower end of the suction pile (11) using a room-temperature curing adhesive (20); the suction pile (11) with the air peg (19) attached is lifted using a land crane (16) and a lifting device (17), and precisely inserted and placed into the outer surface of the air peg cone (18) already installed on the upper part of the pontoon (12). This characterizes the composite modular suction pile and fused offshore wind foundation structure. System. Claim 12 In claim 11, the suction pile (11) is firmly fixed on the pontoon (12) to create a watertight environment for internal ballasting during launching, and to ensure airtightness and watertightness between the lower inner surface of the suction pile (11) and the air peg cone (18) of the pontoon (12), an aramid fiber-reinforced polyurethane air peg (19) is placed at the bottom of the suction pile (11) and attached and cured using a room-temperature curing adhesive (20), the suction pile (11) with the air peg (19) attached is inserted into the air peg cone (18), and air is injected into the air peg (19) through a compressor hose (22) at a pressure of 40 to 50 bar, and the air peg (19) is strongly adhered to the outer surface of the air peg cone (18), thereby completely sealing the connection between the suction pile (11) and the pontoon (12) to prevent internal flooding. A composite modular suction pile and fused offshore wind foundation structural system characterized by forming a watertight structure that prevents water leakage. Claim 13 A composite modular suction pile and fused offshore wind foundation structure system according to claim 12, wherein the suction pile (11) module is inserted and installed into the air peg cone (18) on the upper part of the pontoon (12), and a ring connector (9) body having a skirt structure that prevents scour of the seabed by dispersing the upper load transmitted from the suction pile (11), wherein each steel plate constituting the outer wall is aligned and welded together to form an integrated outer casing structure, and to secure the structural rigidity of the ring connector (9), a horizontal bulkhead (55) with a thickness of 35 mm, a bulb flat (56), and a vertical bulkhead (58) with a thickness of 35 mm in a 5-way method are arranged in a grid pattern inside the body and each joint is welded to complete an internal reinforcing frame, and the ring connector (9) is lifted using a land crane (16) and a lifting device (17), and aligned and welded to the upper part of the suction pile (11). Claim 14 In claim 13, the assembly of the sub-tower (6) is characterized by the ring connector (9) being welded to the top of the suction pile (11), the outer wall body of the sub-tower (6) being manufactured by rolling steel plates, the sub-tower local buckling prevention stiffener (7) being manufactured and welded to the inner surface of the manufactured sub-tower (6) to ensure structural stability and prevent local buckling, the sub-tower (6) with internal reinforcement completed being lifted using a land crane (16) and a lifting device (17), and the sub-tower (6) being vertically aligned and welded to the upper central position of the ring connector (9). Claim 15 In claim 14, to ensure stability during ground penetration of the foundation structure and to prevent scouring during operation, a scouring prevention skirt (57) is attached to the lower part of the ring connector (9) to penetrate into the ground and block soil loss around the suction pile (11); to suppress deformation caused by internal suction pressure and external earth pressure of the suction pile (11), a suction pile local buckling prevention stiffener (10) is installed inside the suction pile (11); a grid-shaped beam (51) is installed on the top of the suction pile to resist the upper pressure generated during penetration; to withstand the concrete load poured into the interior to suppress the upward force of the sub-tower (6), a grid-shaped beam (52) is installed on the floor of the sub-tower between the bottom surface of the sub-tower (6) and the upper deck of the ring connector (9); and to ensure rigidity and control operation of the sub-tower (6), an internal sub-tower local buckling prevention stiffener (7), suction A composite modular suction pile and fused offshore wind foundation structure system characterized by installing a hose (31), a concrete hose (36) for concrete pouring, an air vent pipe (52), a compressor hose (22), and an automatic valve (open, close) (54) for flow control, installing a work platform (59) to support the joining process of the post tower (3) and the turbine (2), constructing a suction pile and sub-tower ballasting system (8) for filling seawater inside the suction pile (11) and the sub-tower (6) to stably sink the composite modular foundation structure into seawater, and maximizing structural rigidity by densely arranging a bulb flat (56), a 35 mm thick horizontal bulkhead (55), and a 5-way 35 mm thick vertical bulkhead (58) inside the ring connector (9) so that a 6-degree-of-freedom load transmitted from the sub-tower (6) can be distributed and transmitted to the suction pile (11). Claim 16 In claim 15, after completing the installation of a composite modular foundation structure including the suction pile (11) on the upper part of the pontoon (12), pressure sealing to completely seal the space between the air pack cone (18) and the suction pile (11) is achieved by operating an air compressor (21) provided on the pontoon (12) to inject air pressure into the aramid fiber-reinforced polyurethane air pack (19) attached to the lower end of the suction pile (11) through a compressor hose (22), and by controlling the pressure inside the aramid fiber-reinforced polyurethane air pack (19) to reach 40 bar to 50 bar to expand the aramid fiber-reinforced polyurethane air pack (19), thereby causing the aramid fiber-reinforced polyurethane air pack (19) to be strongly compressed between the outer surface of the air pack cone (18) of the pontoon (12) and the inner surface of the suction pile (11). A composite modular suction pile and fused offshore wind foundation structure system characterized by forming a completely sealed structure that blocks the inflow of seawater into the suction pile (11) during launching. Claim 17 In claim 16, the composite modular foundation structure is placed on top of the pontoon (12), and a monitoring system is installed to maintain long-term soundness during installation and operation. This involves densely arranging fiber optic sensors (FBG) (71), which are resistant to electromagnetic interference, along the weld lines of the sub-tower (6) and the ring connector (9) where stress is concentrated, to determine the strain distribution of the structure in real time. The fiber optic sensors (71) are attached to the surface or embedded using an epoxy-based adhesive and secured with protective metal clips. Acoustic emission (AE) sensors (72) are placed on the inner and outer sides of the joints of the sub-tower (6), the suction pile (11), and the ring connector (9) to capture elastic waves when micro-cracks occur. The acoustic emission sensors (72) are attached using an epoxy or silicone-based adhesive, and a coupling agent is applied between the sensor and the structure to improve signal transmission efficiency. Smart wireless accelerometers (73) are fixed to the top of the post tower (3) and the sub-tower (6) using bolt fastening and clamping methods to detect the natural frequency of the structure. A composite modular suction pile and fused offshore wind foundation structure system characterized by installing a device for monitoring the decrease in rigidity due to changes, installing a device for supplying power to sensors by attaching an energy harvesting device (74) utilizing micro-vibrations and wave energy to the structural contact area of ​​the sub-tower (6) and the ring connector (9) by welding or bolting, and installing a corrosion-resistant casing (75) made of titanium or specially coated stainless steel to protect each sensor and communication cable from seawater corrosion, wherein the casing (75) is fixed to the internal frame of the structure by welding or bolting. Claim 18 In claim 17, loading a composite modular foundation structure placed on top of the pontoon (12) and stabilizer (13) from the quay (24) to a semi-submersible barge (23) for marine transport involves controlling the draft and trim of the barge by adjusting the flow rate of the ballasting tank provided inside the semi-submersible barge (23) in real time so that a horizontal state is maintained between the quay (24) and the semi-submersible barge (23), and while the skid rail (15) installed on the quay (24) and the rail on the upper deck of the semi-submersible barge (23) are aligned with each other, the assembly of the pontoon (12) and stabilizer (13) on which the foundation structure is placed is moved horizontally via a skid shoe (14) to be transferred to the semi-submersible barge (23), and the stability and horizontal state of the semi-submersible barge (23) are continuously maintained in response to load changes occurring during the loading process. A composite modular suction pile and fused offshore wind foundation structural system characterized by completing shipment by performing precision ballasting to maintain stability. Claim 19 A composite modular suction pile and fused offshore wind foundation structure system according to claim 18, wherein the assembly of the pontoon (12) and stabilizer (13) on which the composite modular foundation structure is placed is loaded into the upper deck position of the semi-submersible barge (23), and the heel and trim during the loading process are restored through ballasting control of the semi-submersible barge (23) to secure a horizontal state, and the pontoon (12) and the upper deck of the semi-submersible barge (23) are firmly fastened together by welding a binding device or a binding member to prevent movement of the foundation structure due to external forces during maritime transport. Claim 20 In claim 19, the towing for transporting the composite modular foundation structure loaded on the semi-submersible barge (23) to the installation site is characterized by concentrating the towing load by connecting two strands of towing wire ropes (43) extending from the bow side of the semi-submersible barge (23) to one link plate (44), connecting a main towing wire rope (43) to the opposite side of the link plate (44) and connecting it to the two strands of ropes, connecting the end of the main towing wire rope (43) to a tugboat (25), and then using the propulsion force of the tugboat (25) to tow the semi-submersible barge (23) loaded with the foundation structure to a set offshore installation location. Claim 21 In claim 20, the launching preparation performed when the semi-submersible barge (23), towed by the tugboat (25), arrives at the set offshore installation site is characterized by mooring the semi-submersible barge (23) to the set installation coordinates, releasing the fastening device installed between the pontoon (12) and the semi-submersible barge (23) for offshore transport, and injecting seawater into the ballasting tank provided inside the semi-submersible barge (23) to slowly sink the barge while maintaining a horizontal position, thereby allowing the pontoon (12) and the composite modular foundation structure placed on the upper deck of the barge to come into contact with the sea surface and secure their own buoyancy. Claim 22 In claim 21, the precision sinking for floating the pontoon (12) and the composite modular foundation structure on the sea through ballasting of the semi-submersible barge (23) is characterized by continuously injecting seawater into the ballasting tank of the semi-submersible barge (23) to slowly sink the barge in a horizontal state, and when the sinking depth of the semi-submersible barge (23) reaches 5.3m relative to the upper deck and reaches a critical state just before the pontoon (12) and stabilizer (13) combination separates from the barge due to its own buoyancy, the ballasting speed is controlled to further sink the barge by measuring the stability and horizontality in real time, and so that the pontoon (12) and the composite modular foundation structure are safely separated from the semi-submersible barge (23) to form an independent floating state, thereby forming a composite modular suction pile and fused offshore wind foundation structure system. Claim 23 In claim 22, the final launching for completely floating the pontoon (12) and the composite modular foundation structure on the sea through precision ballasting of the semi-submersible barge (23) is characterized by controlling the ballasting speed by decelerating it while monitoring the magnitude of the buoyancy received by the pontoon (12) and stabilizer (13) combination in real time from the point where the sinking depth of the semi-submersible barge (23) reaches 5.3m relative to the upper deck, and by carefully further sinking the semi-submersible barge (23) to a final target depth of 7m, thereby completely separating the pontoon (12) and the composite modular foundation structure that were placed on the upper deck of the barge from the barge and converting them into an independent floating state by their own buoyancy. Claim 24 In claim 23, the completion of launching the pontoon (12) and the composite modular foundation structure, which have secured their own buoyancy by the sinking of the semi-submersible barge (23), by completely separating them from the upper area of ​​the barge is characterized by connecting a towing wire rope (43) to each of the semi-submersible barge (23), the pontoon (12), and the stabilizer (13) assembly, and connecting them to individual tugboats (25) or multiple tugboats, and moving each of the tugboats (25) in mutually opposite directions or in a direction that allows for securing a safe separation distance, thereby physically separating the pontoon (12) and stabilizer (13) assembly in a floating state and the semi-submersible barge (23) in a sinking state. Claim 25 In claim 24, the control for stably sinking the pontoon (12) and the composite modular foundation structure, which have been separated from the semi-submersible barge (23) and are in a floating state, to the seabed is such that, in order to prevent overturning and ensure structural stability during sinking, the balance between buoyancy and weight is precisely controlled by using a marine crane (26) to support the upper load and applying a downward load to the foundation structure through a stability load device (27), and by operating a ballasting compressor (61) to inject seawater into the stabilizer bulkhead (66) tank and the pontoon bulkhead (67) tank, which are respectively independently partitioned inside the stabilizer (13) and the pontoon (12), through the stabilizer ballasting pipe (62) and the pontoon ballasting pipe (64), and by individually controlling the stabilizer ballasting valve (ON, OFF) (63) and the pontoon ballasting valve (ON, OFF) (65) during the injection process to adjust the ballasting amount of each tank, thereby A composite modular suction pile and fused offshore wind foundation structure system characterized by maintaining the horizontal state of the foundation structure while slowly sinking it, and ballasting seawater using the suction pile and sub-tower ballasting system (8) inside the suction pile (11) which is watertightly attached to the air pack cone (18), thereby finally sinking the entire composite modular foundation structure vertically toward the seabed. Claim 26 In claim 25, the vertical sinking control for settling the pontoon (12), which has been separated from the semi-submersible barge (23) and is in an independent floating state, and the composite modular foundation structure on the seabed is performed by supporting the upper load with a marine crane stability adjustment (26) to prevent overturning caused by changes in stability and flow occurring during sinking, and by operating the stability load device (27) to apply a downward load to the foundation structure to actively adjust the weight balance corresponding to buoyancy to secure structural stability, and by supplying compressed air from the ballasting compressor (61) and selectively injecting seawater into the stabilizer bulkhead (66) compartment tank inside the stabilizer (13) and the pontoon bulkhead (67) compartment tank inside the pontoon (12) through the stabilizer ballasting pipe (62) and the pontoon ballasting pipe (64), and during the injection process, the stabilizer ballasting valve (63) and the pontoon ballasting A composite modular suction pile and fused offshore wind foundation structure system characterized by controlling the opening and closing of valves (65) individually to precisely control the amount of ballasting for each compartment tank, thereby maintaining the horizontal alignment of the foundation structure and allowing it to sink slowly, and by operating the suction pile and sub-tower ballasting system (8) to fill additional seawater into the suction pile (11) which is watertightly connected to the air pack cone (18), thereby finally causing the entire composite modular foundation structure to sink vertically toward the seabed. Claim 27 In claim 26, the removal and separation for separating and lifting the pontoon (12) and stabilizer (13) assembly from the composite modular foundation structure sunk to the seabed is achieved by opening the compressor air valve (28) connected to the compressor hose (22) to completely discharge the pressurized air inside the aramid fiber-reinforced polyurethane air pack (19) that was sealing the space between the air pack cone (18) and the suction pile (11), thereby releasing the fastening force by the aramid fiber-reinforced polyurethane air pack (19), and controlling the stabilizer ballasting (ON, OFF) valve (63) and pontoon ballasting (ON, OFF) valve (65) connected to the ballasting compressor (61), the stabilizer ballasting pipe (62), and the pontoon ballasting pipe (64) to the compartment tanks of the stabilizer bulkhead (66) and the pontoon bulkhead (67). A composite modular suction pile and fused offshore wind foundation structure system characterized by performing ballasting or de-ballasting, and by precisely adjusting the inclination and buoyancy of the pontoon (12) and stabilizer (13) combination through ballasting or de-ballasting, thereby gradually separating the pontoon (12) combination upward from the air peg cone (18) of the suction pile (11) settled on the seabed, and physically completely separating the pontoon (12) and stabilizer (13) combination from the composite modular foundation structure and causing it to float to the sea surface. Claim 28 In claim 27, the pontoon (12) and stabilizer (13) assembly and the composite modular foundation structure are completely separated, and the recovery of the pontoon (12) and stabilizer (13) assembly to land is performed by controlling the floating speed and horizontality of the assembly in real time through a marine crane stability adjustment (26) and a stability load device (27) in order to maintain the stability of the pontoon (12) and stabilizer (13) assembly separated from the foundation structure, while maintaining the interior of the suction pile (11) settled on the seabed in a submerged state, and securing stable support of the foundation structure by operating the suction pile and the sub-tower ballasting system (8) to selectively de-ballast the seawater filled inside the sub-tower (6), and connecting a towing wire rope (43) to the pontoon (12) and stabilizer (13) assembly and using a tugboat (25) from the foundation structure installation point A composite modular suction pile and fused offshore wind foundation structure system characterized by separating them by a safe distance, operating the ballasting compressor (61), stabilizer ballasting pipe (62), pontoon ballasting pipe (64), stabilizer ballasting (ON, OFF) valve (63), and pontoon ballasting (ON, OFF) valve (65) to discharge seawater from the compartment tanks of the stabilizer bulkhead (66) and the pontoon bulkhead (67), thereby securing buoyancy so that the pontoon (12) is exposed above the sea surface, leveling it, and then towing it back to the onshore quay (24). Claim 29 In claim 28, the suction penetration and soil treatment for finally penetrating the composite modular foundation structure settled on the seabed to the design depth is performed by operating the marine crane stability adjustment (26) and the stability load device (27) to maintain the verticality of the structure, and by using the self-weight of the suction pile (11) to initially penetrate it into the seabed ground. After the initial penetration is completed, the automatic valve (open, closed) (54) connected to the suction hose (31) is opened, and the suction manifold (29) and suction pump (30) installed on the marine crane (33) are operated to suck in seawater and soil inside the suction pile (11), thereby penetrating the suction pile (11) into the ground using the internal and external pressure difference generated by sucking in the seawater and soil inside the suction pile (11). After transferring the soil sucked in by the suction pump (30) to the soil temporary storage (32), the soil is discharged. A composite modular suction pile and integrated marine wind foundation structure system characterized by environmentally friendly dredging that minimizes pollution caused by suspended matter in seawater by guiding and discharging it to the seabed surface through a pipe (34). Claim 30 In claim 29, the final penetration and settling of the composite modular foundation structure to the design depth through the generation of continuous negative pressure using the suction pump (30) is achieved by vertically lowering and penetrating the suction pile (11) until the lower end of the suction pile (11) and the scour prevention skirt (57) provided on the outer surface of the ring connector (9) reach the seabed ground, and by ensuring that the scour prevention skirt (57) is completely penetrated into the seabed ground and the lower surface of the ring connector (9) comes into close contact with the ground, a blocking structure is formed to prevent ground scour around the suction pile (11), and the flow rate flowing through the suction hose (31) is controlled by controlling the opening and closing of the automatic valve (open, closed) (54) during the penetration process, and the suction through the suction manifold (29) and suction pump (30) provided on the marine crane (33) A composite modular suction pile and integrated marine wind foundation structure system characterized by continuously sucking up soil inside the pile (11), transferring the sucked-up soil to the soil temporary storage (32), and then guiding and discharging it to a location near the seabed through the soil discharge pipe (34) to prevent changes in seawater turbidity and the spread of pollution. Claim 31 In claim 30, after the suction pile (11) and the ring connector (9) have been fully driven into the seabed ground to the design depth, since the suction pile (11) has weak pull-out resistance underground, the self-weight increase and internal filling to resist the uplift force occurring during the operation of the structure are applied to the internal space of the sub-tower (6) to secure pull-out resistance by applying a structural load to the internal space of the sub-tower (6), and concrete filling (35) is formed by pouring plain concrete up to the design required height, and concrete supplied from a marine ready-mix concrete unit (37) placed on the marine crane (33) or on the upper part of the work vessel is pumped into the interior of the sub-tower (6) through a concrete hose (36) to fill the space so as to be integrated with the lower bottom surface of the sub-tower (6) and the upper part of the ring connector (9), thereby increasing the total self-weight of the foundation structure and minimizing the tensile stress transmitted to the suction pile (11). This characterizes the composite modular suction pile and fused offshore wind foundation structure. System. Claim 32 In claim 31, after the installation of the sub-tower (6) and the filling of the interior concrete are completed, the fabrication and installation of the upper tower for stacking and joining the upper structure, the post tower (3), is performed by first forming the main body of the post tower (3) by rolling and welding an outer steel plate at a land-based fabrication plant, installing a post tower local buckling prevention stiffener (4) on the inner circumference of the post tower (3) to prevent local buckling, and pre-fabricating and attaching a post tower installation stabing cone (5) to the lower end to induce precise joining with the lower structure, loading the fabricated post tower (3) onto a marine crane (33) and transporting it to the installation site, then using a post tower installation device (40) equipped on the marine crane to vertically lift and erect the post tower (3), and inserting the post tower installation stabing cone (5) at the bottom of the post tower (3) into the upper opening of the sub-tower (6) settled on the seabed, thereby vertically connecting the upper and lower towers A composite modular suction pile and fused offshore wind foundation structure system characterized by performing coaxial alignment and temporary installation, circumferentially welding the joint between the sub-tower (6) and the post tower (3) on a work platform (59) installed on the upper part of the sub-tower (6), and finally completing the installation of the upper structure by performing weld quality inspection including non-destructive inspection. Claim 33 In claim 32, after the installation of the post tower (3) is completed, the installation of an upper power generation unit for stacking and combining a power generation turbine (2) and a turbine blade (1) on the upper part of the post tower (3) is characterized by transporting the turbine (2) and the turbine blade (1), which are loaded on a separate transport barge, to the offshore installation site, lifting the turbine (2) and the turbine blade (1) using the offshore crane (33), operating the turbine and blade installation device (42) provided on the offshore crane (33) to perform vertical alignment and temporary installation by inserting the stabbing cone (5) provided at the bottom of the turbine (2) into the upper opening of the post tower (3), welding the joint between the post tower (3) and the lower frame of the turbine (2) on a work platform (59) installed on the upper part of the post tower (3), and performing a weld quality inspection including non-destructive testing to complete the installation of the turbine (2) and the turbine blade (1), and the composite modular suction pile and fusion Offshore wind power foundation structure system.

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