The variation of the seabed may cause the scour around the the foundation of bottom-supported platform in nearshore oilfield, when the platform is fixed on the seabed. For the severe consequences that may cause the slip of platform especially instability of the structure, which need to be paid more attentions in offshore engineering to make it work safely. So it's important and necessary to investigate the characteristic of scour and take effective measures to prevent it. In this paper, scale models are adopted in experiment to study the scour of bottom-supported platform in currents.
It can be observed clearly that the basic characteristic of scour and the evolving tendency of the foundation of the platform through the experiment of two different scales in currents. The area where could be scoured more easily is concluded by analyzing the results. Scour pit pattern and scour depth also can be got through the measurements by ultrasonic topography device. At the same time the maximum scour depth around the foundation of platform can also be inferred based on the scale models theory, which will be helpful for the more sdudy about scour prevention. And it will also have conductive effect for such engineering problem.
Soft soil are widely distributed in Chinese Bohai nearshore region, especially in Dagang, Liaohe and Jidong offshore oilfield, which could induce scour around submersible platform foundation in drill or explore process. Sediment scour of platform foundation could induce platform slide, even lose the stability, which threaten platform safety. Foundation scour is the most important issue of submersible platform safety operation.
Wang (1998) carried out scour experiment around submersible platform foundation in wave and current interaction. The results showed that there were scour area under platform foundation and scour holes in front and side of foundation look like U shape. Wave and current interaction increase scour probability, mainly because of the large-scale eddy erosion and current transportation. Zhong (2003) analyzed scour process and principle around platform foundation in Chengdao oilstate and researched scour origin and velocity of pile foundation, which provide reliable reasons for design and construction. Han (2006, 2007, 2009) researched the silty sand scour around artificial island and structure through series model theory and analyzed the sand scour variation under different combination of wave and current.
In order to investigate scour ability around submersible platform and take anti-scour method to protect the platform foundation, series model theory was adopted to research scour character around submersible platform. The experiment was carried out in wave tank of CNPC key laboratory of Offshore Engineering.