"Why, as part of engineering surveys — specifically geological surveys — do we assess the corrosive aggressiveness of soils, including corrosion from stray currents?"
1. Why is this a task for geology and geophysics?
Soil is a complex electrolytic environment. Our task is to assess all risks to the future structure within the geological environment. Stray currents are one of the most aggressive and hazardous factors.
We carry out:
- Analysis of the corrosive aggressiveness of soils (chemical and biological corrosion).
- Measurements to assess the corrosion hazard caused by stray currents (both alternating and direct).
If there are tram lines, power lines, an electrified railway, or simply old underground utilities with leaks near your site, "parasitic currents" appear in the soil. Our geophysics team will "see" them.
2. This is necessary so that your underground structure doesn't fail prematurely.
- Metal structures (pipelines, tanks, piles).
- Foundations with a metal frame (for example, steel piles).
For example, say you built a building on steel piles. Nearby is a tram line. Stray direct currents from the rails "seek" a path to ground and use your piles as that very path. The result is electrochemical corrosion accelerated many times over. A structure designed for 50 years can be destroyed in 10-20.
3. This is a direct regulatory requirement
SP 11-105-97 (Part V, "Engineering and Geophysical Surveys") directly specifies the need for these studies.
GOST 9.602-2016 (Unified System of Corrosion and Ageing Protection
UNDERGROUND STRUCTURES. General Requirements for Corrosion Protection) describes the methodologies in detail.
Conclusion: Assessing the risk of stray current corrosion is not an "optional extra," but a mandatory element of quality engineering surveys.
It enables the design of proper anti-corrosion protection (sacrificial anodes, cathodic protection) and can save millions on premature repairs or emergency remediation.
