Methods to Evaluate Corrosion in Buried Steel Structures: A Review

Abstract

Around the world, there are thousands of metal structures completely or partially buried in the soil. The main concern in their design is corrosion. Corrosion is a mechanism that degrades materials and causes structural failures in infrastructures, which can lead to severe effects on the environment and have direct impact on the population health. In addition, corrosion is extremely complex in the underground environment due to the variability of the local conditions. The problem is that there are many methods to its evaluation but none have been clearly established. In order to ensure the useful life of such structures, engineers usually consider an excess thickness that increases the economic cost of manufacturing and does not satisfy the principles of efficiency in the use of resources. In this paper, an extended revision of the existing methods to evaluate corrosion is carried out to optimize the design of buried steel structures according to their service life. Thus, they are classified into two categories depending on the information they provide: qualitative and quantitative methods. As a result, it is concluded that the most exhaustive methodologies for estimating soil corrosion are quantitative methods fed by non-electrochemical data based on experimental studies that measure the mass loss of structures.

Improving the diagnostics of underground pipelines at oil­and­gas enterprises based on determining hydrogen exponent (PH) of the soil media applying neural networks

“…Sour, alkaline and neutral soils are the main types of natural soils [1]. It was noted in [2,3] that electrolytic composition of the soil medium significantly influences rate of growth of defects such as cracks in the pipe steel. Specifically, it was proven in [4,5] that many factors influence the process of soil corrosion of underground metal structures, namely, water content, chemical composition and pH value of the medium, electrical resistance, soil type, salinity, noise, porosity, etc.…”

“…The main types of failure of underground metal pipelines (UMP) of oil-and-gas enterprises include [1,2]: 1) mechanical failure of structural material; 2) corrosion as an arbitrary process of metal failure caused by electrochemical, chemical, biochemical interaction with the medium.…”

“…3) electrolyte flow rate; 4) contact with other metals, etc. Hydrogen exponent (pH) of soil media is the most important of all above-mentioned technological factors which influences rate of corrosion failure of oil-and-gas enterprise UMPs [1][2][3]. The factors determining influence of corrosion activity of soils on the UMP metal show difficulty of diagnosing oil-and-gas enterprise UMPs in soil media.…”

“…The factors determining influence of corrosion activity of soils on the UMP metal show difficulty of diagnosing oil-and-gas enterprise UMPs in soil media. As is well known, the list of main factors includes [2,4,5]:…”

Design of Predictive Models to Estimate Corrosion in Buried Steel Structures

“…The existing literature on the corrosion of steel in soil shows a lack of a clearly established method in the dimensioning of buried metal structures [10]. The engineer responsible for the design of the structure estimates the amount of steel required for each project.…”