Research on Scour Protection Technology for Submarine Cable Based on Grid-like Frame Structure

Submarine cable is the main channel for transmitting offshore wind power, a clean energy source, and facilitating the mutual support of cross-regional clean energy resources. The requirements for its safety and reliability are increasingly stringent. Influenced by ocean currents, submarine cable is susceptible to be scoured, leading to exposure and suspension, which can compromise its safe operation. This paper presents a design for an scour protection device for submarine cable featuring a net-like frame structure. The hollowed-out structure can reduce ocean currents without directly blocking the water flow, thereby avoiding local scour caused by conventional heavy-load protection methods such as rock-dumping and interlocking concrete mats. Through numerical calculations and simulation analyses of 7 protective devices with different structural configurations under various working conditions, it has been confirmed that the best scour protection effect is achieved when the number of horizontal and vertical reinforcement bars in the outer support frame is 7×3 and the inclination angle of the outer bearing is 15°. Under a current speed of 2 m/s, the flow obstruction effect approaches 70%. Field tests conducted in a certain sea area showed that when the maximum ocean current speeds reached 0.35 m/s, the device exhibited a significant impeding effect on the bottom water flow within its interior. The internal flow velocity trends remained consistent with those outside but were consistently limited to below 0.1 m/s, achieving a flow obstruction effect of approximately 70%. This can effectively promote the sedimentation of sediment carried by the water flow near the submarine cable, weaken the cylindrical wake effect caused by exposed cable sections, and protect the submarine cable from scouring.