DnV96版《海底管道系统规范》对冲击防护的新规定

在海底管道设计中要考虑到在整个海底管道运行期间（通常是20～30年）管道有可能受到由水面船只上掉下的物体或船只拖网鱼具的冲击。在海底管道设计和建造中通常都按挪威船级社的《海底管道系统规范》（以下简称DnV规范）的规定进行设计建造。由于DnV81版规范中对受到冲击后的管道变形没有明确的规定，因此在管道设计中通常是不考虑钢管受冲击后变形的，而DnV96版规范中对受到冲击后的管道变形做了明确的规定，在某些情况下钢管受冲击后变形可达到钢管直径的3.5％，按DnV96规范设计的管道可减少混凝土涂敷的厚度，从而达到降低成本的目的。

In the designation of marine pipe, it is possible that the pipe may be impacted by the objects fallen from the vessels or by the trawlnet during the service life (usually 20～30 years). Usually the design and construction of marine pipe is built in accordance with the Marine Pipe System stan-dard by Norway Ship’s Classification Soclety. Because the pipe deformation is not clearly pressented after in the DnV81 Version, the factor of the pipe deformation is not considered. But in the DnV96, the pipe deformation after shock is clearly prescribed. In certain case, the pipe deformation may reach 3% of the pipe diameter after the shock. According to the DnV96, the concrete coating thickness may reduced so as to lower the construction cost.