This type of optical cable is sheathed with a steel belt or steel wire and is directly buried in the ground. It is required to have resistance to external mechanical damage and to prevent soil corrosion. According to different conditions and conditions of use of different protective layer structure, for example, in areas with pests and rats, to use a cable with an insect-resistant bite. According to the difference between soil and environment, the depth of buried cable in the ground is generally between 0.8m and 1.2m. During laying, care must also be taken to keep fiber strain within allowable limits.
Direct laying should meet the following requirements:
- Avoid areas with severe acid or alkali corrosion or serious chemical corrosion; when there are no corresponding protective measures, avoid the termite damage zone and heat source, or the sections that are easily damaged by external forces.
- The optical cable should be laid in the trench, and the soft cable or sand layer with a thickness of not less than 100mm should be covered around the optical cable.
3, along the full length of the cable should cover the width of not less than 50mm on both sides of the optical cable protection board, protection board should be made of concrete.
- Laying position In places where urban roads and other frequent excavation are frequent, you can use a prominent logo strip on the protective floor.
- In the laying position of the suburbs or open-air belts, obvious azimuth signs or stakes shall be erected along the straight line spacing of the optical cable path at about 100mm, the turning point or the joint.
- When laying in non-frozen areas, the cable sheathing to underground structures shall not be less than 0.3m, and the depth of cable sheaths to the ground shall not be less than 0.7m. When located on roadways or under cultivated land, they shall be properly deepened and shall not be less than 1m.
- When laying in the frozen soil area, it should be buried below the frozen soil layer. When it cannot be buried deeply, it can be buried in dry and frozen soil layers or backfill soil with good drainage, and other measures to prevent damage to the optical cable can also be taken. .
- When the optical cable route laid directly buried intersects railways, roads or streets, protective pipes shall be worn, and the protection scope shall be more than 0.5m above the roadbed, the two sides of the street pavement, and the side of the drainage ditch.
- In the case of direct-buried optical fiber cable introduction structures, protective pipes should be installed at the through-holes, and the pipes should be blocked by water blocking.
- The net distance between the joints laying the optical cable directly and the adjacent optical cables should not be less than 0.25m; the joint positions of the parallel optical cables should be staggered with each other, and not less than 0.5m net distance; the joint position at the slope topography should be horizontal; for the important circuit The optical cable connector should have a spare cable laying method at the local section starting at about 1000mm on both sides.