Analysis of the Pipelines Functional Safety on the Mining Areas

Buried pipeline systems, which transports water, sewage, oil or gas, perform the substantial role in urban areas. Sometimes their safe functioning is hampered because of damages caused in mining areas. In this article a characterization of the influence of mining activities on underground pipelines was presented. A description and classification of damages to pipelines with reference to mining influences were given of the various different pipelines systems and pipes materials. An illustrative example of damages to the stoneware sewage pipeline located on the mining area was presented. The effort of such pipe was carried out with using numerical methods (FEM). Model 2D represented stoneware pipe-soil system influenced by traffic load (SLW60) and the mining ground deformations (horizontal strains increasing from 0 to 9 mm/m). Model was built in ZSoil.PC program. The numerical analysis was performed as incremental and iterative. On the basis of the obtained results of numerical analysis (internal forces) the safety factors for various pipes classes with different bending strength were determined. Moreover, functional safety of the spigot-and-socked joints subjected mining impact was also assessed. During increasing of mining impact the insertion length at joints should provide free movement of spigots inside the socket, without losing the join tightness. It has been shown that the insertion length at analyzed stoneware pipes joints wasn’t appropriate which may result in damage of the spigot-and-socked joints during increasing the mining ground deformations.