Characteristics of buried pipelines and anti-corrosion layer requirements

In recent years, many cities in my country have built sewage treatment plants. Most of the water pipelines in urban sewage treatment projects are steel pipes laid underground. Corrosion problems are a major problem in sewage treatment projects. The quality and lifespan of buried water pipelines directly affect the entire project. Therefore, it is very important to prevent corrosion of buried pipelines in urban sewage treatment projects.

Characteristics of buried pipelines
Corrosion characteristics
The corrosion of buried pipelines in urban sewage treatment projects is mainly soil corrosion, which is characterized by scattered pipeline layout and complex soil conditions, so the corrosion mechanism is complex.
Soil corrosion includes electrochemical corrosion and microbial corrosion caused by salt, water, oxygen, etc. in the soil and steel pipes. Because urban underground electrical facilities and cables are relatively dense, the corrosion caused by stray current is also relatively serious. Pipelines passing near factories may even be chemically corroded by acid or alkali media.
Force characteristics
Urban buried pipelines often pass through roads, buildings, rivers, etc., and their pressure conditions are complex. In addition, the pipeline may be damaged by the collision and extrusion of stone and sand during the buried backfill process.
Difficulty in maintenance
Once buried pipelines are damaged by corrosion, they are difficult to inspect and repair, aggravating corrosion. Environmental damage is often caused during maintenance. Due to this characteristic, the design life of buried pipelines and their corrosion protection is generally required to be more than 20 to 30 years.
Anti-corrosion layer requirements
According to the characteristics of urban buried sewage pipelines, the anti-corrosion layer of the pipeline should meet the following basic requirements:
①Has good chemical corrosion resistance;
②Good insulation performance and compactness to prevent electrochemical and stray current corrosion;
③Resistant to bacterial corrosion;
④Have certain mechanical strength to prevent mechanical damage during transportation and burial;
⑤The construction is simple and safe, and meets the on-site construction requirements.
In addition, there are some special requirements in special areas, such as cold resistance.