J形保护管距海底泥面高度对海底电缆强度的影响

J形保护管为海底电缆提供外部保护，避免其在波浪海流载荷作用下产生较大的移动变形，但运营期海底局部冲刷改变了海底电缆出泥点位置，导致海底电缆发生悬空，影响其结构强度。应用OrcaFlex软件建立分析模型，针对不同局部冲刷深度和不同重现期下的环境参数，采用非线性时域方法对海底电缆的结构状态进行评估。经计算，海底电缆的最小弯曲半径是限值工况，出现在J形保护管喇叭口区域。当J形保护管距海底泥面高度由0.315 m变化至1.500 m时，1 a重现期的最小弯曲半径为3.106～3.526 m,波动范围为13.5%,100 a重现期的最小弯曲半径为2.835～3.123 m,波动范围为10.2%,海底电缆在百年一遇工况下更危险。

Influence of Height Between J-tube and Submarine Mud Line on Strength of Submarine Cable

J-tube provides external protection for submarine cables to avoid large movement and deformation under wave and current loads. However, due to local scouring of the seabed during the operation period, the location of the submarine cable''s mud outlet is changed, resulting in free spanning of the submarine cable, which affects its structural strength. OrcaFlex software is used to establish an analysis model. For the environmental parameters under different local scour depths and return periods, the nonlinear time domain method is used to evaluate the structural state of the submarine cables. According to the calculation results, the minimum bending radius of the submarine cable is a limit condition, which occurs in the bell mouth area of the J-tube. When the distance between the J-tube and the submarine mud line changes from 0.315 m to 1.500 m, the minimum bending radius during a 1-year return period is from 3.106 m to 3.526 m, with a fluctuation range of 13.5%. The minimum bending radius during a 100-year return period is from 2.835 m to 3.123 m, with a fluctuation range of 10.2%. The submarine cables are more dangerous under a 100-year return period.