波浪-地震对海底管道垂直弯曲段力学状态的影响研究

考虑波浪力和地震波载荷的影响,通过载荷和约束简化推导穿越强震区海底管道在波浪载荷和地震波载荷作用下的运动方程和状态方程,进而得到海底管道垂直弯曲段应力和轴向应变的影响因素;通过数值计算对海底管道垂直弯曲段强度随剪切波速、管径、壁厚、弯管角度及海底土体性质的变化规律进行研究。结果表明:在地震波和波浪力共同作用下,海底管道垂直弯曲段最大应力出现在弯管下部位置;同一工况下波浪载荷比震波荷载对管道垂直弯曲段最大轴向应力的影响更大;实际海底管道设计时应优先采用大直径、大壁厚管道,管道垂直弯曲段弯管设计角度不大于30°。研究结果为特定区域现场施工提供了技术支持,对海底管道设计中的选管、几何形状优化提供科学依据。

Study on the Influence of Wave Pseudo-earthquake on Mechanical State of Submarine Pipeline Vertical Bending Section

Motion equation and state equation was derived for subsea pipeline across the earthquake zone under wave loads and seismic wave load by simplifying the loads and constraints.Then factors about stress and axial strain were obtained.The strength variation of subsea standpipe affected by wave velocity,pipe diameter,wall thickness,bending angle and subsea soil properties was studied by numerical calculation.The result showed:the maximum stress of subsea standpipe occurred at the elbow lower position in the seismic waves;greater mechanical impact the wave loads were provided to the standpipe than the earthquake under the same conditions;actual design of the subsea standpipe should give priority to larger diameter and wall thickness and the bending angle of the rise should be designed less than 30°.The conclusion of the study provides technical support for the material selection and geometry optimization of subsea pipeline design and construction.