Mechanics Analysis Of Clamping Load On Ocean Platform Foundation Pile And Research On Its Series Devices

In recent years, with the rapid development of marine engineering technology, seabed oiland gas and offshore wind power generation have drawn more and more attention fromcountries all over the world. This paper originates from two scientific research projects fromChina National Offshore Oil Corporation (CNOOC), Large-scale Offshore Wind TurbineInstallation Process and R&D of Deepwater Jacket Hydraulic Pressure Installing Facilities.The subjects investigated are offshore oil platform jacket piling bar and offshore wind turbineimpeller bearer piling bar, which are both called ocean platform foundation pile. At present,the offshore construction techniques about the two kinds of piling bars are both monopolizedby overseas companies. A set of standard offshore operation equipment has not beendeveloped in China where the relevant basic theory and installation techniques have justbegun to be studied recently. Therefore, this paper is set in the offshore installation techniquesabout ocean platform foundation pile, extracts the common problems with the mechanicalprinciples and makes autonomous development and experimental study about a series offoundation piles gripping devices and hangers in the basis of the characteristics of theoverseas products, and finally concludes the technical theory that can guide the offshoreoperation.The analysis of the present status of the home and broad research and development isdone and the summary of jacket foundation pile leveler, the underwater operation of skirt pilegrippers and the hoisting operation technology of offshore wind turbine impeller bearerfoundation piles is made in the paper. Analyze the buckling deformation of the foundation pileunder radical force and do the research on the features and patterns of buckling deformationunder certain size of load; make the study of local plastic deformation of the foundation pileunder the clamp pressure and integral stability.After doing researches and analysis on clamping institutions load-bearing mechanicalproperties, the design principles of the foundation clamping mechanism are determined.Analyze the load-bearing principles of the clamping mechanism, including analyzing bendingand shear resistance on the pressing tooth embedded in base metal, tooth point deforming andstress，constant strength tooth point minimal contour，conical chuck ring bending stress andanalysis about the contact issues of the foundation pile.The base pile bilateral spreader with wedge block sliding self-locking symmetricalclamping, the base pile unilateral spreader with dual cam rotating self-locking unilateralclamping and the foundation pile grippers underwater are researched separately based on its function and motion principle, while the appearance and structure of abroad are consideredand learned. The experimental studies break the monopoly of foreign technology and achievethe independent innovation development of these devices.According to the control requirements of series base pile clamping devices for hydraulicactuators, the force feedback control and the displacement synchronous control of thehydraulic system are studied. The displacement synchronous control loops of inter-groupbranch and master-slave servo among groups and the hydraulic circuit controlled by pistonforce with sign feedback are designed respectively; Open loop and closed loop mathematicalmodels are established, while the transfer functions of synchronous displacement and forcecontrol are export; PID control parameters for displacement synchronous control and forcecontrol are ensured through system simulation analysis and research.Finally, the principle prototypes of ocean foundation pile bilateral clamping spreader,base pile unilateral clamping spreader and the foundation pile grippers underwater aredesigned and manufactured, and then the relevant experiment studies are carried out to verifythe correctness of theoretical analysis and the rationality of design.