According to the traffic safety situation in the restricted sea area of Zhoushan, this paper builds a three-dimensional dynamic ship field from the horizontal and vertical directions; then, on the basis of the ship domain model, the three-dimensional space collision risk and time collision risk sub-models are established. Additional risk weighting is carried out for special cargo ships that are prone to accidents by investigating, collecting and analyzing accident data and ship dynamic data; then, the risk degree of these three sub-risk factors is comprehensively considered to establish a systematic comprehensive evaluation model of navigable risk in Zhoushan restricted sea area and the risk level of collision accidents; finally,the case of collision between General cargo ships and fishing boats is used to verify this. This model is innovative in the field of building three-dimensional dynamic ships. In addition, not only the external risk factors but also the additional risks in the transport of special cargo are considered in the assessment of navigable risk. Compared with most of the other models, the three-dimensional dynamic field is used to calculate the collision risk between ships which not only considers the hazard in the horizontal direction, but also covers the hazard in the vertical direction and has good integrity. The analysis of the results shows that the collision risk degree obtained by the comprehensive assessment model of navigation risk can effectively evaluate the collision risk degree of the ship during the course of traveling and can provide a reference for the ship's collision avoidance decision-making and navigation safety.
Zhoushan sea area is one of the busiest sea areas in China, with Yangtze estuary in the north and Xiangshan Bay in the south. With the development of China's economy, zhoushan sea area has brought unprecedented opportunities, limited zhoushan sea area will also face the needs of navigation expansion and greater water traffic safety challenges. The higher the traffic density of ships in different regions, the higher the collision risk. Due to the high risk of accidents, it is necessary to carry out empirical studies on various risk factors affecting traffic safety in Zhoushan sea area and put forward reliable quantitative analysis methods (Chen,2020).