Submarine cables are wrapped in insulating materials

Cable laid on the seabed for telecommunications transmission

It can be divided into submarine communication cables and submarine power cables

Submarine power cable

The laying of submarine cables mainly includes three stages: cable route survey and cleaning (before), submarine cable laying (during), and burial protection (after).

Before laying submarine cables - cable routing survey

  This includes: cleaning up the water depth, terrain, shallow geological profile measurement, sediment surface sampling, columnar sampling, and static cone penetration survey of the offshore routing area, as well as investigating traffic and construction conditions and obstacles that reflect the status of marine development activities.
  Recently, the use of advanced GPS post-processing positioning and cone penetration testing (CPT) technology has greatly improved survey speed and effectiveness.

Submarine cable laying - recognized as a complex and difficult large-scale project

  When laying submarine cables, it is necessary to control the cable's entry angle and laying tension by controlling the sailing speed of the laying vessel and the cable release speed, in order to avoid damaging the cables due to small bending radius or excessive tension.
  In shallow waters, such as those with a depth of less than 200 meters, cables are buried. In the deep sea, cable laying is used, where cables are released by cable laying ships and continuously monitored and adjusted using underwater monitors and remote control vehicles. The speed, direction, and cable laying speed of the laying ship are controlled to avoid uneven areas and rocks and damage to the cables.

After laying submarine cables - burial protection

  In the final stage of construction, the main focus is on deep burial protection of submarine cables, reducing the impact of complex marine environments on submarine cables and ensuring safe operation.

  In sandy and muddy areas, high-pressure flushing is used to create a trench about 2 meters deep, where cables are buried and covered with sand nearby; In coral reefs and clay areas, cut a 0.6-1.2-meter-deep trench with a cutting machine, bury the cable in the trench, and naturally backfill to form protection; In hard rock areas, it is necessary to cover the cables with hard objects such as cement cover plates for protection.