Physical mechanisms of typical risk sources and classification analysis of risk modes for sea ice disasters on marine engineering structures are explored in the study. Based on 22 accidents and 14 potential risk cases, the risk sources of sea ice disasters on marine engineering structures are classified and 6 sea ice disaster sources (extreme ice force, dynamic ice force, ice jamming, etc.) are proposed. The structural failure modes and main influencing factors of sea ice disasters on marine engineering structures are demonstrated. Based on the physical mechanisms of sea ice failure and removal, risk sources and failure modes are summarized for three dominant kinds of marine engineering projects in China (platform, port, and nuclear power facilities). The risk mode analysis of sea ice disasters in the study provides the technical support for marine engineering structures in the design stage, operation stage, and risk assessment and emergency stage.
The icing phenomenon occurs every year in the Bohai Sea and the northern Yellow Sea, which are the ice-covered sea area with the lowest latitude in the northern hemisphere in China. International studies on sea ice disasters began in the early last century (Sanderson, 1988) and China has also carried out relevant studies for more than forty years (Bao, 1991; Yang, et al, 1993; Sun, et al, 2011). The sea ice disasters are the third largest marine disasters in China. Since the 20th century, more than 20 sea ice disasters have occurred in the Bohai Sea, including 5 severe ice disasters respectively in 1936, 1947, 1957, 1969, and 1977. According to the statistical data of sea ice disasters (Yang, et al, 1993), medium and severe sea ice disasters in the whole Bohai Sea and Yellow Sea occurred once approximately every 5 to 6 years and sea ice disasters in local sea areas occurred almost every year. The sea ice disasters have attracted widespread attention since the No. 2 offshore platform was overthrown by sea ice in 1969. In the sea ice disaster in early 2010, some ports and navigation channels were frozen and a large number of aquaculture products died, thus resulting in a direct economic loss of nearly ¥ 6.4 billion (Zou et al. 2011; SOA, 2010).