The operational reliability of pipeline systems in the conditions of Western Siberia is determined mainly by the ability of the pipeline structure to provide an operational position under the influence of destructive geological processes within the limits of acceptable values. Frost heaving of soils is most dangerous process for “warm” and “cold” pipelines, which is associated with huge forces and small absolute deformations because it don’t allow well-time diagnosis in high snow cover and absent of a planned-high-altitude position monitoring system. To date, design solutions for engineering protection of pipelines against frost heaving do not provide a standard level of reliability, which makes the problem of increasing the efficiency of engineering protection more important.
The authors divided the engineering protection methods into two groups: the first group reduces the heaving properties of the soil; the second group reduces forces from the side of heaving soil. The article shows the results of the numerical study of engineering protection methods of the second group. Analysis of the results showed an increased danger of local frost heaving with a length of no more than 21 m for main pipelines with a diameter of 530 to 1420 mm in comparison with longer ones. It proves the necessity of using the engineering protection on the all distance from the well with heaving soil to the well with non-heaving soil. Reducing the restrained capacity of adjacent non heaving soils reduces the stress-strain state in heaving areas. However it increases the risks of emerging and arch formation in engineering and geological conditions of Western Siberia and is not recommended for use. The use of soil bedding made of non-heaving materials under the bottom of pipe to reduce the forces and displacements from frost heaving can significantly reduce the stress-strain state of the pipeline. The numerical study of the bedding geometric parameters, carried out by the authors of the article, showed that the bedding made of materials more rigid than the soil of the ground should be deeper, and less rigid should be wider, due to the difference in protective properties.
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