Directly buried fiber optic cable This kind of optical cable is armored with steel tape or steel wire on the outside and buried directly in the ground. It is required to have the performance of resisting external mechanical damage and preventing soil corrosion. Different sheath structures should be selected according to different use environments and conditions. For example, in areas with pests and rodents, optical cables with sheaths that prevent pests and rodents from biting should be selected. Depending on the soil quality and environment, the depth of the optical cable buried underground is generally between 0.8m and 1.2m. When laying, care must also be taken to keep the fiber strain within the allowable limits.
Direct burial laying should meet the following requirements:
1. Avoid areas with strong acid and alkali corrosion or severe chemical corrosion; if there are no corresponding protective measures, avoid termite-hazardous areas and areas affected by heat sources or areas that are easily damaged by external forces.
2. The optical cable should be laid in the trench, and the surrounding area of the optical cable should be covered with soft soil or sand layer with a thickness not less than 100mm.
3. The entire length of the optical cable should be covered with a protective plate with a width not less than 50mm on both sides of the optical cable. The protective plate should be made of concrete.
4. The laying position is in places where excavation is frequent, such as urban access roads, and an eye-catching sign belt can be laid on the upper layer of the protection board.
5. At the laying position located in the suburbs or open areas, obvious azimuth signs or stakes should be erected at the straight line interval of about 100mm along the optical cable path, at the turning point or at the joint.
6. When laying in non-frozen soil areas, the cable sheath to the foundation of the underground structure should not be less than 0.3m, and the depth from the cable sheath to the ground should not be less than 0.7m; when it is located on the roadway or cultivated underground, it should be properly deepened, and should not be less than 1m.
7. When laying in permafrost areas, it should be buried below the permafrost layer. When it cannot be buried deeply, it can be buried in dry permafrost layer with good soil drainage or backfill soil, and other measures to prevent damage to the optical cable can also be taken. .
8. When the optical cable line laid directly buried intersects with railways, highways or streets, protective tubes should be worn, and the protection range should exceed 0.5m above the roadbed, both sides of the street and the side of the drainage ditch.
9. When the optical cable laid directly buried is introduced into the structure, a protective tube should be installed at the penetrating slope hole, and the tube mouth should be blocked by water blocking.
10. The clear distance between the connector of the directly buried optical cable and the adjacent optical cable shall not be less than 0.25m; the joint positions of the parallel optical cables should be staggered from each other, and the clear distance shall not be less than 0.5m; the position of the connector on the slope terrain shall be horizontal; for important circuits It is advisable to leave a spare way to lay the optical cable at the local section starting from about 1000mm on both sides.