As for the prevention of cable floating bodies, it is a systematic work involving the entire process of design, construction, and operation and maintenance. Cable floating bodies usually refer to the phenomenon where underwater or submarine cables are detached from the seabed/riverbed due to external factors (such as water flow, waves, ship interference) and suspended in water. This will bring serious risks such as cable wear, insulation damage, and even breakage.

Here are comprehensive preventive recommendations, which can be addressed from the following stages:

I. Planning and Design Phase (Root Cause Solution)

This is the most fundamental and economical prevention link.

1. Accurate Marine/Hydrographic Survey:

◦ Water flow data: Detailed measurement of flow velocity, direction (including surface and bottom currents), tidal patterns, wave data, etc. in the route area. Avoid laying cables in strong current areas or eddy areas.

◦ Seabed topography and geology: Using multi-beam echo sounding and side-scan sonar, accurately master the seabed topography (avoiding gullies and steep slopes) and geological conditions (such as sand waves and silty seabeds prone to erosion). Select a flat, stable, and non-erodible seabed route.

2. Scientific Cable Selection and Design:

◦ Unit weight: Calculate according to water flow velocity and select sufficiently heavy cables (such as thickened armor layer), using their self-weight to maintain stability. \”Double armor\” or special heavy-duty outer sheath design can be adopted. ◦ Outer sheath: Use wear-resistant materials (such as polyethylene PE) to cope with occasional slight friction.

◦ Dynamic cable design: If used for floating structures (such as offshore wind power), it should be specially designed as a \”dynamic cable\”, whose structure can withstand continuous bending and movement.

3. Rational Protection Plan Design:

◦ Burial protection: This is the most effective method. Use submarine cable plows or jet-burial machines to bury the cable at a certain depth below the seabed (usually 1.5 meters to 3 meters, determined according to geology and risk level). The burial depth should be able to resist expected scouring and external interference.

◦ Covering protection: In sections where burial is not possible or additional protection is needed (such as landing points and channel intersections), use:

■ Concrete weights/cover plates: Directly cover the cable to provide stable pressure.

■ \”Saddle-shaped\” weights: Better fit the cable shape.

■ Stone/gravel coverage: Place the cable in a pre-dug trench and then backfill and cover with appropriately sized stones. ◦ Flexible protection devices: Such as \”protection mattresses\”, used to cover the cable to prevent suspended sections from being worn.

II. Construction and Installation Phase (Precision Execution)

Even the best design needs high-quality construction to ensure.

1. Accurate Cable Laying:

◦ Control tension and slack: Maintain appropriate tension during laying and reserve a certain \”S-shaped\” or \”wavy\” slack so that the cable can naturally conform to the seabed, avoiding being pulled straight and suspended due to excessive tension.

◦ Real-time monitoring: Use underwater robots (ROVs) to monitor the cable’s seabed condition and attitude in real time, ensuring that it is laid along the designed path and tightly against the seabed.

2. Ensure Burial/Protection Quality:

◦ Verify burial depth: After burial, use probes on ROVs or shallow subsurface profilers, etc., to sample and check whether the actual burial depth of the cable meets the design requirements.

◦ Ensure protection is in place: Check whether weights, stone coverage, etc., are uniform, tight, and there are no missed points.

III. Operation and Maintenance Phase (Continuous Monitoring)

After cable laying, the environment may change, requiring continuous monitoring and maintenance.

1. Regular Route Patrols:

◦ Acoustic Detection: Regularly scan the cable route using multi-beam echo sounding and side-scan sonar, compare with historical data to identify seabed topography changes (such as scour pits, sand wave migration) and newly emerged suspended sections.

◦ ROV Inspection: For key sections with identified issues, dispatch an ROV for underwater video and measurement to accurately assess the length, height, and risk level of the suspended sections.

2. Establish a Risk Early Warning Mechanism:

◦ Cooperate with marine and meteorological departments to monitor extreme weather events such as typhoons and giant waves, which may drastically alter seabed morphology. Strengthen patrols after such events.

3. Timely Maintenance Intervention:

◦ Once risk-prone suspended sections are detected, timely remedial measures should be taken, such as:

■ Throw sandbags or stone materials: Fill and support below the suspended section.

■ Install additional weights: Add weights above the suspended section.

■ Perform back-digging and burial: For longer suspended sections, secondary burial construction may be required.

Summary: Key strategies for preventing cable buoyancy

planning and design

Avoid risks and enhance self-respect

Detailed hydrological survey, selection of stable routes, design of heavy cables, priority adoption of buried schemes

construction and installation

Precise laying to ensure protection

Control the laying tension and slack, use ROV for real-time monitoring, and strictly verify the burial depth and installation quality of protective devices

maintenance

Continuous monitoring and timely intervention

Regular acoustic and ROV inspections, establishing an early warning mechanism for extreme weather, and rapid repair of suspended sections

Core Idea: Preventing cable floating bodies is a ‘system project’, which must start from the source (design). Through refined construction and continuous maintenance, a complete closed-loop management should be formed to maximize risk reduction and ensure the safe and stable operation of cable lines. ‘Prevention is better than cure’; investing more in preliminary design and construction is much cheaper than post-incident emergency repair and restoration.