Research On Ship Collision Risk Assessment Method Of Offshore Wind Turbine Single Pile Foundation

At present,a large number of offshore wind farms built in China are offshore and close to the port and waterway,which has a certain impact on the navigation safety of ships.As the number of offshore wind farms continues to increase,although there has not been a major collision between wind turbines and ships,research on the risk assessment of collisions between offshore wind turbines and ships cannot be ignored.Some foreign countries and organizations have conducted risk assessments for many offshore wind power projects,and are trying to establish a unified risk assessment method to formulate guidelines for the safety risks of offshore wind farms.However,a single risk assessment method is not applicable to the marine environment and navigation conditions of different countries and regions.However,domestic research on quantitative risk assessment of ship collisions in offshore wind farms is quite lacking.Obviously,there is an urgent need to formulate comprehensive risk assessment criteria in China to ensure the safety of offshore operations and marine environmental protection around offshore wind farms.In this thesis,combined with the research on ship collision risk assessment at home and abroad,with a wind farm in the offshore of Fujian as the research background,a quantitative risk assessment model for ship collision on a single pile foundation for offshore wind turbines is established.The main research results are as follows:(1)Through the investigation and analysis of wind farms,the environmental factors,ship factors and human factors that affect the risk of collision between wind turbines and ships have been identified;The geometric probability calculation model of ship drift collision and dynamic collision is briefly introduced,and the probability of drift and dynamic collision is calculated to be 0.0141 and 0.00474 respectively.(2)The risk probability analysis method combining fault tree and multi-state Bayesian network and multi-source information fusion method are applied to establish the causal probability calculation model of wind turbine and ship collision;The Bayesian network model is quickly constructed through the fault tree,and then the conditional probability table is obtained through the analytic hierarchy method and the triangular fuzzy number comprehensive expert score and historical data.The drift and dynamic collision probabilities of the ship and the wind turbine are calculated to be 0.04599 and 0.03879,respectively,and the importance of risk factors is analyzed.(3)The MSC.Dytran program was used to simulate the dynamic process of a certain type of wind power hoisting ship hitting the single pile foundation of an offshore wind turbine at different speeds under drift and dynamic collision.The impact energy and structural stress and strain of the wind turbine pile foundation structure and the cabin The displacement acceleration is analyzed.(4)Through the ALARP principle and risk matrix,the acceptance criteria for the collision risk of a single-pile wind turbine and a ship were determined,and the risk assessment of the single-pile foundation affected by the ship collision under different collision conditions and the influence of different risk factors was carried out.It is found that the risk of dynamic collision exceeding 3m/s is completely intolerable,and measures to reduce the risk of offshore wind turbines from collisions with ships have been proposed.(5)A ring-shaped steel structure anti-collision facility for single-pile foundations was designed,the collision damage of the single-pile foundation with anti-collision structure was calculated,and the collision risk evaluation was carried out.Comparing with the risk of no anti-collision structure,it is found that the dynamic collision risk level of 3m/s is reduced by two levels,from completely intolerable risk to tolerable risk,which proves that installing anti-collision facilities is an extremely effective collision risk reduction measure.