海洋自升式平台桩靴触底碰撞动力学研究

Dynamics Research on Collision of Marine Jack-up Platform Spudcan and Seabed

海洋自升式平台在桩腿下放、拔起以及迁移过程中,桩靴与海底会发生碰撞接触的情况。为此,研究了海洋自升式平台桩靴触底碰撞动力学分析方法,采用ANSYS/LS-DYNA软件建立桩靴-海底有限元模型,研究不同速度和不同碰撞角度下桩靴碰撞海底动力学特性。研究结果表明,刚碰到海底时桩靴顶板、壳体和骨架应力集中在中心区域,隔板应力分布比较均匀;随着碰撞时间的延长,桩靴壳体底部应力逐渐变大,顶板、隔板和骨架应力逐渐变小;随着碰撞速度的增大,桩靴最大应力发生的时间依次提前,速度小于3.0 m/s时桩靴的最大应力均在屈服强度之内;桩靴与海底碰撞角度越大,桩靴的最大应力也会增大,在速度为1.5 m/s、角度为3°时桩靴应力达到屈服强度。相关研究成果可为桩靴的设计校核与作业技术提供参考。

Due to heave of sea, uneven seabed, improper operation and other reasons, the spudcan could collide with the seabed when pile legs of the marine jack-up platform are lowered, pulled up and migrated. In order to solve this problem, a dynamic analysis method is studied on collision of marine jack-up platform spudcan and seabed. A seabed FE model is built by using ANSYS/LS-DYNA software to study dynamic properties of collision between spudcan and seabed under different velocities and collision angles. The study results show that the stress of spudcan top plate, shell and framework is concentrated in the central zone, and baffle stress is distributed uniformly when the spndcan just collides with the seabed; with the collision time going, the shell bottom stress gradu- ally increases while the stress of top plate, baffle and framework gradually decreases; maximum stress of the spudcan occurs earlier when the collision velocity rises and it remains within the range of yield strength when the velocity is below 3.0 m/s; maximum stress of the spudcan increases with the collision angle, and it reaches the yield strength under the velocity of 1.5 m/s and collision angle of 3°.