Study On System Safety Modal Of Channel Navigational Environments

Waterway transport is a transportation mode of high risk. Due to the complexity of natural and hydrological environment, as well as the flaw of the waterways, ships may suffer some accidents during navigation. Meanwhile, with the development of waterway transport, ships tend to larger size, more specialized and higher speed. On the other hand, the traffic density in inland waters and ports are more intensive then before. All the above result is an increasing risk for the waterway transport.Analytic hierarchy process, factor analytic process and other methods are frequently applied to the domestic and foreign waterway transport safety research to extract safety factors of navigable environment system. On the basis of acquiring of safety factor state, mathematical statistics, fuzzy theory and gray theory are applied to analyze and assess system safety state. The above research methods provide effective approach to analyze system safety factors and system safety state in a specific condition. In terms of the system dynamic characteristic, space distribution field of the individual safety factors in navigable environment system are studied to build the general expression of system safety modal and research the system safety characteristics as well as its evolution. The research is significant to make a more in-depth study and understanding of the impact of the system safety driver.The thesis studies the system safety modal of channel waters navigation environments taking the western Shenzhen port channels for example. Principle elements related to the system safety are extracted and the spatial distribution and modal characteristics are studied. To this aim, firstly, the paper makes the grids of channel water and gathers AIS data, maritime accidents and natural environment data; Secondly, it studies the space distribution flied of the factors in channel navigation environment, build the mapping function of system safety modal to the factors, and establish the general expression of system safety modal. Finally, based on the work above, the study makes an analysis on safety features comprehensively and evolution characteristics of the safety modal of channel navigable environment. So far, the main results of this paper can be concluded as follows.1. The channel navigation environment element fields (especially vessel traffic density and velocity) are described and analyzed by means of two-dimensional fields. In a macroscopic point of view, the analytic way intuitionally describes the navigable environment factor distribution of channel waters. In a microscopic point of view, the analytic way provides the information of channel navigable environment elements in unit water area.2. The general expression of the safety state of vessel traffic flow and the natural environment-ship system safety modal are established respectively. Based on the expression, the modal features and evolution characteristics of the system are analyzed by drawing spatial-distribution maps of system safety modal.3. The general expression of vessel traffic flow and natural environment-ship system safety modal are combined to compose the general expression of the safety modal of channel navigation environment system and obtain variation characteristics of safety modal in different system modal. On the basis of catastrophe theory, the thesis analyzes the mutation characteristics and evolution mechanism of navigable environment of channel waters by selecting specific safety factors, and provides solid support for decision-making system.