Application of mathematical modeling methods to determine the effect of soil on natural vibration frequencies of pipelines

When a pipeline is subjected to an external influence that can affect the frequency of its natural vibrations, the parameters of its natural vibrations change, which increases the measurement error, and often simply distorts the results of vibration control. For pipelines, such an impact may be the influence of the soil when pipelines are laid without a channel. Different types of soil affect the change in the natural vibration frequency of the pipeline in different ways.
The purpose of the article is to analyze the influence of various types of soils on the parameters of natural vibrations of the pipeline. The aim of the study was to theoretically confirm the dependence of the change in the frequency of vibration of the pipeline under the influence of soil.
A modal analysis of natural oscillations of 5 polyethylene pipelines was performed. As initial data, it is assumed that the design pipeline is laid in a trench with inclined walls, with the slope laid on a flat base at a depth of 2.5 m. The calculations were performed in the ANSYS finite element analysis software package. In order to build a mathematical model, the degree of soil impact on pipelines is determined by studying the vertical and lateral pressure of the soil on the above pipelines, and the natural vibrations of pipelines are analyzed.
The results of the modal analysis for polyethylene pipes with a laying scheme with inclined walls and different soils (gravel sands, coarse and medium-sized; heavy clays) are presented. The soils were chosen that are the most common on the territory of Russia.
Thus, the obtained dependence of the degree of influence of different soil on the natural frequencies of pipelines significantly increases the reliability of vibration diagnostics of buried communications, can facilitate the work on its organization and allow determining long-term forecasts of pipeline operation.

1. Berzin P. O. Control and diagnostics of heat and power equipment. In the collection of materials in the VIII All-Russian, scientific and practical conference of young scientists with international participation "Young Russia", Kuzbass State Technical University named after T. F. Gorbachev 2016;: 325.

2. Gerasimova A. G. Principles of choosing materials for heat and power equipment and pipelines of TPP. Science – education, production, Economy: proceedings of the 14th International Scientific and Technical Conference 2019; 1: 91.

3. Dudorov V. E., Timofeev I. S. Analysis of accidents at pipeline transport facilities (oil, oil products). Fundamental research of the main directions of technical and physical-mathematical sciences. Collection of articles on the results of the International Scientific and Practical Conference 2018; : 71–74.

4. Nikulin N. Yu., Kushchev L. A., Temnikov D. O. Modern technological aspects of the development of heat supply systems. Modern construction and Architecture 2016; 4 (04).

5. Sazonova S. A., Sushko E. A. Development of methods and algorithms for technical diagnostics and ensuring the safety of fire extinguishing systems, heat, water, and gas supply and industrial technological pipelines. Modern problems of civil protection 2017; 2 (23): 40–45.

6. Dmitriev A. V. Investigation of the frequency of free vibrations for pipelines with different physical and mechanical properties of the material. Online magazine "Transport Facilities" 2020; 1.

7. Koval A. I., Medvedev A. E. Measures of technical diagnostics of the state of pipelines. Materials of the III All-Russian Student Scientific and Technical Conference 2017;: 97–98.

8. Gaponenko S. O., Ibadov A. A., Kondratyev A. E. Determination of informative frequency ranges for monitoring the location of buried pipelines. Scientific progress – the creativity of the young. Povolzhsky State Technological University 2018; 2: 68–71.

9. Shlychkov D. I. Problems of the technical condition of existing pipeline systems. Innovation and Investment 2020; 4: 207–210.

10. Prodous O. A., Vasilyeva M. A. Simplified type of normative dependence for hydraulic calculation of pipelines made of polymer materials. Water supply and sanitary engineering 2017; 9: 53–56.

11. Vikulin P. D. Hydraulics and aerodynamics of water supply and sanitation systems. National Research Moscow State University of Civil Engineering 2018;: 386.

12. Fedorova N. N., Valger S. A., M Danilov.N., Zakharova Yu. V. Osnovy raboty v programmnom complex ANSYS 17 2017;: 210.

13. Sekacheva A. A., Pastukhova L. G., Noskov A. S. Modeling of dynamic characteristics of a vertical pipeline element. Collection of reports of the VII All-Russian Scientific and Practical Conference with International Participation 2019;: 334–341.

14. Baykova L. R., A Novikov N. V. The use of the software package of the finite element method in the study of hydrodynamic parameters and vibration of pipelines. Transportation and storage of petroleum products and hydrocarbons 2020; 3.

15. Gaponenko S. O., Kondratiev A. E. Perspective methods and methods of searching for hidden channels, cavities and pipelines by vibroacoustic method. Bulletin of the North Caucasus Federal University 2015; 2(47): 9–13.

16. Nazarychev S. A., Gaponenko S. O., Kondratiev A. E. Determination of informative frequency ranges for monitoring the location of a buried pipeline. Spiral 2018; 8: 2481.