海洋石油隔水管承载力动测分析研究

海洋石油隔水管具有长径比大和壁厚较薄等突出特征。采用动力试验检测隔水管竖向承载力时常常忽视残余应力的影响，导致结果准确性低。依托某实际工程，开展隔水管现场动力试验和波动拟合计算承载力研究，分析连续锤击下管土体系动力响应特性以及残余应力产生和作用机理，提出残余应力分析方法。通过承载力和压、拉应力计算及其对比分析可知，考虑残余应力的计算结果更能反映管土体系实际受力状态，可有效地修正上部土阻力高估和下部土阻力低估导致的误差，以提高计算承载力和应力分布的准确性。试验结果表明，考虑残余应力时隔水管承载力略高于不考虑残余应力结果；压应力在隔水管上部低于而在下部高于不考虑残余应力结果；拉应力结果与压应力相反。研究成果对隔水管在海洋石油钻井工程中安全应用方面具有十分重要的现实意义。

Dynamic test of bearing capacity of offshore oil-drilling risers

Offshore oil-drilling risers have large length-to-diameter ratios and thin walls. The effect of residual stress is often neglected in the dynamic test on the vertical bearing capacity of risers, which leads to low accuracy of results. Based on a practical project, field dynamic test and wave fitting method were adopted to calculate the bearing capacity of risers. The dynamic characteristics of a riser-soil system and mechanism of residual stress generation and action under continuous hammering were analyzed, and the analysis method of residual stress was presented. Calculation and comparative analysis of bearing capacity, compressive stress, and tensile stress were performed, and the calculation results considering residual stress reflect well the actual stress state of the riser-soil system and effectively correct the error caused by the overestimation of upper soil resistance and underestimation of lower soil resistance, and the accuracy of bearing capacity and stress distribution can be improved. The results show that the bearing capacity of risers considering residual stress is slightly higher than those without residual stress. Compressive stress is lower in the upper part and higher in the lower part of risers than that without considering residual stress, and the result on tensile stress is opposite that of compressive stress. Research results have practical importance in the safe application of risers in offshore oil-drilling engineering.