Design Theory And Monitoring Of Mooring Underwater Storage Tank

Increased ability to crude oil reserves is a important guarantee to improve the national energy security,the coastal land resources shortage and ground crude oil reservoir of location and the safe distance of urban residential requirements make dramatically increased the difficulty of crude oil reserve capacity increasing along the coast,so development of nearshore shallow waters of the crude oil storage facilities gradually on the agenda.The underwater storage tank is the core equipment of crude oil offshore storage.The design theory of tensioning mooring underwater storage tank is studied in this thesis,and the main principles and analysis methods of load bearing design,emplacement design and monitoring design are described in detail.The mooring simulation test was carried out by using microwave wave pool to explore the complex mechanical relationships among incoming wave composition,tank motion,tank slosh and mooring cable tension.Aiming at the relationship between tank motion response and mooring cable tension,a mooring cable tension monitoring method based on tank motion signal was preliminarily formed.The main research contents of this thesis include:(1)The structural form of a single-layer thin-wall carbon steel underwater storage tank and its tensioning mooring emplacement strategy are demonstrated.The feasibility of the scheme is proved by the detailed design and calculation of the tank.The FroudeKrylou wave diffraction pressure borne by the tank during underwater emplacement is calculated by using the linear wave theory,and the stability of underwater emplacement is checked.(2)In view of the extreme conditions,the confining pressure of the nonlinear analysis of bearing capacity tank empty cans,paper,eigenvalue buckling analysis is utilized to extract tank crushing mode,and build tanks rolled out of roundness,and then using the method of modified Riks analysis of elastic-plastic deformation process of tank crushing,tank under external pressure deformation buckling failure and the sequence of yield failure,The rationality of the designed storage tank in stability is tested.(3)The use of pressure wave microwave wave pool,slightly linear wave is studied under the action of mooring motion response of storage tank model,obtained under different combination of wave,velocity and acceleration of floating body model threeaxis duration curve,at the bottom of the mooring line tension and pressure change of realtime data,contrast the loading capacity of motion response characteristics and the influence of the mooring force,The data reflecting the hydrodynamic characteristics of the tensioned mooring in the frequency domain are obtained,and the reliability of the experimental results is partially verified by Orcaflex model.(4)According to the wave force and related motion differential equation of floating body moving under regular wave,a monitoring method of mooring cable tension is proposed by calculating the movement data of storage tank,and another storage tank model with larger scale is used to carry out the verification experiment of monitoring principle.At the same time,the liquid sloshing in the model tank is studied,which provides support for further improving the prediction accuracy of wave load on the tank.