Is directly buried cable corrosion resistant?

　　The corrosion resistance of directly buried optical cables is the key to ensuring their long-term stable operation. The following is a detailed analysis from the aspects of technical principles, material design, environmental adaptability and industry standards:

　　First, anti-corrosion structural design

　　Directly buried cables are protected against corrosion by a multi-layer protective structure.

　　Metal sheath: Usually aluminum or steel sheath is used to provide basic mechanical protection, but its corrosion resistance is limited.

　　Polyethylene (PE) outer sheath: as a core protective layer, it has excellent corrosion resistance and waterproof performance, and can effectively isolate acid, alkali, salt and other chemicals in the soil.

　　Water-blocking layer and anti-corrosion layer: Some optical cables (such as patent model GYTA53) add water-blocking tape and internal anti-corrosion layer on the outside of the optical fiber to form a chemical barrier.

　　Armor layer: Steel strip or wire armour not only enhances mechanical strength, but also partially blocks the intrusion of corrosive substances.

　　Second, the anti-corrosion mechaniSM

　　Chemical protection: PE materials are inert to common corrosive substances (such as acid, alkali and salt) in the soil, forming an effective barrier.

　　Physical barrier: Multi-layer structure (metal sheath + PE + armor) to delay the penetration of corrosive media.

　　Patented enhanced design: such as GYTA53 optical cable, through the synergistic effect of water barrier layer, radiation protection layer, and internal corrosion protection layer, the corrosion resistance life is improved.

　　III. Environmental adaptability and limitations

　　Soil pH:

　　Acidic soil (pH < 6): may accelerate metal jacket corrosion, requiring additional protection (e.g. cathodic protection).

　　Alkaline soils (pH > 8): may also corrode metals, and soil resistivity needs to be taken into account.

　　Moisture content: Humid environments accelerate electrochemical corrosion, and the sealing of the PE sheath becomes crucial.

　　Special scenarios: in highly corrosive areas such as saline-alkali land and swamps, it is recommended to use high-corrosion-resistant materials (such as double-layer PE sheaths) or cathodic protection measures.

　　IV. Industry standards and testing

　　Burial depth requirements: usually requires a burial depth of ≥ 1.2 meters to avoid surface soil tillage or man-made damage.

　　Life test: In laboratory simulated soil, high-quality optical cables can withstand corrosion for more than 30 years.

　　Maintenance Specifications: Construction needs to avoid damage to the outer sheath, and the damaged point needs to be repaired and re-sealed in time.

　　V. Practical application and maintenance recommendations

　　Regular inspection: check whether the cable route has settlement or excavation marks to avoid mechanical damage to the outer sheath.

　　Electrocorrosion protection: In stray current areas (e.g. near railways and power lines), sacrificial anode method or external current cathodic protection is used.

　　Monitoring technology: through air pressure monitoring or electrical performance testing, timely detection of outer sheath breakage points.

　　summarize

　　Directly buried cables are resistant to corrosion through multi-layer material design and structural protection, but additional maintenance measures are required in extreme environments (e.g. saline soils, swamps) or long-term exposure. Users should choose the appropriate model according to specific soil conditions and use scenarios, and follow construction specifications to ensure cable life.