中文摘要：

深水海管在使用卷管铺设时，海管截面变形较大，产生椭圆化现象，降低了海管的弯曲能力，甚至使海管发生失稳及局部屈曲．利用应变能法和Ritz法建立了海管椭圆度理论求解方法．用有限元软件ABAQUS对有初始弯曲曲率及无初始弯曲曲率的海管分别进行了非线性有限元分析，并与modified Brazier方法及modified vonKármán方法得到的结果进行了比较．由以上几种方法得到的计算结果基本吻合．再次利用有限元软件对海管椭圆度的敏感参数进行了分析，多组结果显示椭圆度受海管管径、壁厚、初始弯曲曲率、弯曲曲率等参数的影响，并得到了椭圆度随海管几何参数变化的规律．椭圆度的研究为深海卷管铺设提供了理论基础．

英文摘要：

During the reel-lay installation in deep water, large deformation occurs on the pipe- line, leading to ovalization, instability or even local buckling. Ovality theory was established based on strain-energy method and Ritz method. Also, finite element analysis was employed by software, ABAQUS. The results obtained from the former procedures were compared with those from modified Brazier and modified yon Kármán, serving as a good verification of the for- mer solution. In addition, intact and defective pipelines are separately simulated by ABAQUS, suggesting that ovality is subject to pipeline-diameter, wall-thickness, initial bending curvature and bending curvature,et al. The law between ovality and geometrical parameters is further obtained. The above research of ovality is of certain interest to reel-lay installation.