世越号起吊姿态敏感性分析与方案选择

Sensitivity analysis of Sewol lifting attitude and salvage plan selection

韩国世越号打捞是世界上首次利用托底钢梁原状态整体起吊难船出水的工程。客滚难船装载的货物容易在沉没后发生移位,上层建筑长时间沉没海底后发生泥沙淤积导致难以准确估计整船的重量重心及浮力浮心的位置。利用水池模型试验和数值计算两种方法分别对大型浮吊船单臂架打捞法和双驳船抬吊打捞法进行了难船姿态受重心位置偏移的敏感性分析。水池模型试验中发现,用大型浮吊船单臂架打捞法,世越号的姿态受其重心位置偏移非常敏感,容易发生侧翻;而用双驳船抬吊打捞法,世越号的姿态受其重心位置的影响非常有限,难船和抬浮驳船都可以保持一个较好的姿态。对比水池模型试验的结果,由于难以计及托底钢梁的翘动和滑动现象,数值计算中得到的难船起吊姿态值偏小。双驳船抬吊打捞法被选为打捞世越号的施工方案,其对难船重心位置偏移不敏感的特性得到了现场实证。这个特点为世越号的成功打捞出水起到了关键作用。

Korean Sewol recover^^project is the first project in the world to apply supporting beams to lift the wreck out of water without changing its submerged status.Cargo positions in roro ship can change easily after being submerged.M u d and sands can silt up in super structures which have a large space.Thus,weight and buoyancy of the wreck are very difficult to predict.With model testing and numerical calculation methods,sensitivity analysis of Sewol lifting attitude to its gravity center is conducted for floating crane single boom lifting plan and twin barges lifting plan respectively.Model testing shows that,the calculated Sewol lifting attitude is very sensitive to its gravity center and it potentially rolls over with floating crane single boom lifting method.Sewol lifting attitude is limitedly affected by its gmvity center for twin barges lifting method and barges attitude can also be kept well.Comparing with model testing,the calculated Sewol lifting attitude is too low with numerical method because sliding and seesaw movements of supporting beams under Sewol are not able to be included into numerical model.Twin barge lifting plan is selected to lift Sewol out of water.It is proved that Sewol attitude is stably maintained within the lifting operation.This is the important feature to make Sewol salvage project successful.