Research On Dynamic Calculation Method Of All-vertical-piled Wharf In Offshore Deep-water

Offshore deep-water wharf is the tendency of port and waterway engineeringconstruction，from the domestic and foreign development actuality and the existingengineering practice，pile-bearing platform structure is suitable for offshore deep sea，so it has a broad application prospect. Due to the increase of depth, the extension ofpile, the large of flexible, dynamic response characteristics of structure, wave andstructure interaction, etc are more serious. The traditional design concept, designstandards and calculation methods of offshore structure have not completelyapplicable. But our country still lack further and systematic research on this aspectis.In view of above questions, combined with a actual offshore all-vertical-piled wharfdesign scheme, the paper carry out a series of research on dynamic calculation methodof offshore deep-water wharf. The main content is as follows：1. A3-D elastic-plastic finite element models of foundation and structure wereestablished with ABAQUS. Basing on the criterion of instability, the stability of thestructure under wave load and ship impact force were analyzed, then bearingmechanism and failure mode were made clear and definite.And the influence of theembedded depth of the piles, the thickness of the piles and geological conditions onstructure bearing capacity were also discussed.2. Basing on the existing calculation method of horizontal bearing pile, the thebearing capacity simplified calculation method of all-vertical-piled wharf wererespectively established employing m method and P-Y curve method. Throughcontrasted with the calculation results of the finite element model, the validity wasverified.3. A3-D finite element model of pile foundation structure considering fluidstructure interaction was established with ADINA. By means of numerical simulatingvibration performance of piles in water, the influence of water on self-vibrationcharacteristics and damping ratio on structure were analyzed. Using speed entrancemethod simulate numerical wave, then simulating wave and pile foundation structureinteraction,the effect of fluid and solid coupling interaction on wave force of pileswere analyzed, and a simplified calculation method of wave force amplificationcoefficient considering fluid and solid coupling interaction was established.4. The natural period and mode of vibration for offshore deep-water structurewere studied through numerical simulating, and were compared with the traditional offshore structure to furthur know about mechanics characteristics of offshoredeep-water structure. Wave load and ship impact force were applied to the structure inthe form of dynamic, then the dynamic response of the structure were simulated. Theresults show that the dynamic response of all-vertical-piled wharf under wave loadand ship impact force is similar to the response of single free degree system of the piletop condensed quality, the dynamic magnification coefficient of structural responseunder wave load and ship impact force were obtained.5. Basing on the static simplified calculation method for all-vertical-piled wharf,considering fluid and sturcture interaction and the amplification effect of structuredynamic response，the dynamic simplified calculation method for all-vertical-piledwharf were established to provided guidance and design basis for the engineeringpractice. Through contrasted with the calculation results of the finite element model,the validity was verified.