Research of the Causes of Defects Type “Dent” on the Linear Part of the Main Pipelines

This article discusses the main reasons for the formation of defects such as dents on the main pipelines. As a rule, the presence of dents is typical for laying in conditions of rocky soil or permafrost. In this case, fairly large rock fragments appear at the base of the trench, which act on the pipe with a force equal to the weight of the pipe and the weight of the back fill soil. This is why most of the dents form on the bottom surface of the pipe. As a method of combating the formation of dents, back filling of soft soil at the base of the trench is usually used, but these measures lose their effectiveness because over time the soil from the base of the trench is washed away and the metal of the pipe comes into contact with the stone fragment. This article examines the process of dent formation through numerical simulation. The procedure for modeling is considered, and the results obtained are analyzed. The dimensions and shape of the dents obtained during numerical modeling coincide with the parameters of the dents recorded on real objects. The purpose is to study the mechanism of death formation on large diameter pipes under the influence of static load caused by external force factors. The scientific novelty lies in the refutation of the theory suggesting the possibility of dents on large diameter steel pipelines solely as a result of dynamic action from moving parts of the construction equipment or pipe impact during a fall. The study proved that a dent can form under the influence of static load. The parameters of the dent obtained during the simulation coincide in shape and size with the dents found on real pipelines, which confirms the nature of the formation of dents due to the static effect of the pipe's own weight and the weight of the filling soil. © 2024, Abylkas Saginov Karaganda Technical University. All rights reserved.