PSI - Issue 5

Chmelko Vladimír et al. / Procedia Structural Integrity 5 (2017) 614–619 Garan, M., Chmelko, V./ Structural Integrity Procedia 00 (2017) 000 – 000

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3. The pipeline safety monitoring with corrosive defect The corrosion decrease of the wall thickness is a problem occurring mainly in the line sections of the pipeline. The pipeline systems of the line and distribution sections of the transit pipeline are quasi-statically loaded systems. During their operation a corrosion process takes place in some locations, resulting in a local decrease of material thickness in the pipe wall, which reduces the safety reserves of operation. Another factor that can be associated with the reduction of operational safety is the additional stress from unstable subsoil (pipeline on slope, undermining subsoil, ...). Separate as well as simultaneous action of these phenomena can lead (in a number of cases has already led) to pipeline crashes. The concept of on-line monitoring of the pipeline condition with a corrosion defect located in the soil at the location threatened by landslide and thus with the risk of additional loading stress on the pipeline, loaded by internal gas pressure is shown in (see Fig. 2).

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Fig. 2. Monitoring of safety the pipeline with corrosion defect concept.

The principle of the monitoring system is in a connection of a knowledge about the loading state with corrosion defect and knowledge of the actual depth and size of the corrosion defect. The loading condition can be obtained by continuous measurement using strain gauges, which must be appropriately deployed around the circumference of the pipeline. The location and cross-section suitable for installing sensors can be determined by a combination of two factors:  Pipe inspection for the presence of corrosion defects  Localities with the assumption of additional stress From the known depth of corrosion defect and known or predicted environmental parameters, the parabolic law can be calculated by incrementing its depth h