Dynamic Behavior of Underground Viscoelastic Pipelines Under Seismic Impact in the Form of Real Earthquake Records

4. RESULTS


_{Thus, a system of equations of vibration of an underground polymer pipeline is derived based on the Hamilton–Ostrogradsky variational principle for an arbitrary direction of seismic action, taking into account the interaction of the pipeline with the environment. The SSS of a polymer pipeline under the action of seismic action of an arbitrary direction is investigated, taking into account the influence of the conditions of fixation under the influence of various seismic loads in the form of real earthquake records. Unlike steel pipelines, in polymer pipelines the stresses are an order of magnitude less from the action of real seismic loads. When the end of the pipeline is rigidly fixed to a stationary object, the stress near the fixing point is approximately twice as much as when it is pliable.
All this makes it possible in the future to generally consider the stress-strain state of underground polymer pipeline systems under arbitrarily directed seismic impacts. This provides for further in-depth analysis of the behavior of polymer pipelines based on the calculation results and actual data of earthquakes in the countries of the far and near abroad.
The calculation of an underground structure under the influence of recorded real seismograms takes into account all the features of the seismic process contained in the seismograms, and therefore more objectively characterizes the behavior of the structure under seismic influence, allows you to calculate the true stresses in the body of the object under study. This allows for more accurate calculations of maximum stresses in an underground pipeline and to make a more reliable conclusion about the seismic resistance of a particular pipeline for ground conditions at the construction site and to suggest ways for designers and builders to ensure the seismic resistance of the objects under consideration.}
CONFLICTS OF INTEREST

No conflict of interest was declared by the authors.