海底管道腐蚀后剩余强度评估方法研究

Research on Assessment Method of Remaining Strength of Corrosion Subsea Pipeline

海底管道在服役期间会由于腐蚀而受到不同程度的损坏,进而导致强度降低,影响其安全性。为预测管道腐蚀后的损伤程度,须对腐蚀后管道的剩余强度进行评估。通过计算分析,对腐蚀海底管道剩余强度的分项安全系数法和许用应力两种评估方法进行了详细研究。结果表明:检测腐蚀管道的设备存在误差,即精度不为0时,存在一个相对腐蚀深度(d/t)0,两种方法的评估结果相同;提高设备的测量精度和置信水平,更有利于客观评估腐蚀管道的剩余强度。

Subsea pipe strength will be reduced by corrosion in operation phase, it is necessary to estimate the remaining strength of corrosion pipeline in order to forecast the damage level of corrosion pipeline. Through calculation analysis, the two assessment methods for corrosion subsea pipeline were studied, namely calibrated safety factor method and allowable stress approach. The results show that there is a relative defect depth （d/t）o existed when inspection accuracy is not 0 and the two methods has the same assess- ment result at （d/t） o. Also, the improvement of inspection accuracy and confidence level for inspection equipment will be benefit to assess the remaining strength of corrosion pipeline more objectively.