走滑断层作用下光纤复合海底电缆的力学响应规律研究

Mechanical Responses of Fiber-Optic Composite Submarine Cable Under Strike-Slip Fault Movements

作为一种长距离传输电力和信息的有效工具,海缆难免需跨越断层活动区域。为深入研究断层作用下海缆的力学响应规律与其破坏机制,以典型的走滑断层为依托,利用ABAQUS建立了海床-海缆相互作用的数值仿真模型,得到了海缆典型结构层的位移、应变以及应力等的变化规律。研究结果表明:在走滑断层作用下,海缆的变形大体呈'Z'字形,海缆外被层、铜导体的轴向塑性应变随断层错动位移的增加而增加;海缆外被层可发生明显的开裂甚至剥离变形,同时尽管XLPE绝缘层与镀锌钢丝铠装层的截面变形量均先随断层错动位移的增加先增加而后缓慢下降,但两者变化并不同步;由于断层错动位移所引起的拉-剪应力,海缆整体上表现为张拉破坏。研究方法和成果可为跨断层光纤复合海底电缆的设计和运营维护提供一定的技术指导。

As an effective tool for transmitting power and information over long distances,submarine cables are inevitably required to cross the fault activity area.In order to deeply study the mechanical response and failure mechanism of submarine cable under fault movements,a 3 D numerical simulation model of seabed-submarine cable interaction is established using ABAQUS,and the strain and stress of typical structural layer of submarine cable is obtained.The results show that under the action of strike-slip fault movement,the deformation of the submarine cable is generally'Z'shape,and the axial plastic strain of the outer layer of the submarine cable and the copper conductor increases with increment of the displacement of the fault.Apparent cracking and even peeling deformation can occur in the outer layer of the submarine cable,and although the cross-section deformation of the XLPE insulation layer and the galvanized steel wire armouring first increases and then decreases slowly with the increase of the fault dislocation displacement,the changes are not synchronized.As a result of the tensile and shear stress caused by the dislocation displacement of the strike-slip fault,the submarine cable as a whole presents tensile failure.The research methods and achievements can provide certain technical guidance for the design,operation and maintenance of cross-fault fiber-optic composite submarine cable.