# Study of the Effect of Cutting Frozen Soils on the Supports of Above-Ground Trunk Pipelines
## 1 Introduction  
The global energy market has experienced a substantial increase in demand for energy carriers in recent decades. To address this demand, the construction of reliable oil and gas transportation systems through main pipelines has become crucial. The system of trunk pipelines is a vital component for the efficient functioning of the oil and gas industry and plays a significant role in meeting the essential resource needs of oil and natural gas for the population [1, 2]. Most of Russia's oil and gas reserves are located in Western Siberia, and the routes of the main trunk pipelines run through areas of continuous permafrost distribution. The underground laying of pipelines in such areas is challenging due to various factors. As a result, above-ground construction of trunk pipelines has become a more practical solution [3, 4]. It is important to note that damages to even small sections of pipelines can result in severe consequences, including the loss of raw materials, costly repairs, ecological pollution, and other detrimental effects [5]. The Russian trunk pipeline routes currently span over 500 km through areas with predominant continuous permafrost distribution [6]. Approximately 60% of the total area of the Russian Federation, or 10 million km\({}^{2}\), is covered by permafrost [7]. The construction of an above-ground trunk pipeline requires a complex design and pile foundation supports to ensure stability and reliability. The pile foundations are susceptible to defects, and it is necessary to consider the soil characteristics when selecting the support structures [8]. Operations in areas with continuous permafrost distribution can present challenges due to the climatic and engineering-geocryological conditions of the area, as well as the thermal and mechanical impact of the pipeline and support structures on the natural environment [9]. These challenges can arise from the temperature effects of the pipeline and the mechanical effects of the support structures on the ground. The growth of hazardous cryogenic processes is primarily caused by seasonal thawing and seasonal ground freezing, which leads to the bending of pipelines and the displacement of support structures. The significant volume of frost-heaving soil can result in a loss of the designed position of the above-ground trunk pipeline [10; 11]. During seasonal freezing, the frozen soil rises due to frost heave forces as the water contained in the soil expands upon cooling, causing an increase in ground volume [12; 13; 14; 15]. This leads to the pulling out and displacement of the support structure (Figure 1), which in turn results in a loss of stability for both the support and the pipeline itself [16]. The supports of above-ground trunk pipelines are subjected to loads from the ground resulting from the complex cryogenic processes caused by low temperatures, which have a negative impact on the operational reliability of the pipelines. This could lead to an accident, causing harm to the environment and resulting in significant losses of raw materials. Hence, enhancing the operational reliability of trunk pipelines laid in permafrost soils is of paramount importance [17]. To prevent the effects of the above-mentioned risks, it is necessary to determine the following factors [18]:  
* trunk pipelines are engineering structures of great length and pass-through areas with different engineering-geocryological conditions;
* along the length of the pipeline route, various soil and frost processes take place, which may negatively reveal themselves in the form of frost-heaving bumps. The objective of the study is to enhance the operational reliability of above-ground trunk pipelines constructed on permafrost soils. This is a significant aspect in the realm of oil and gas transportation as it offers the potential to conserve resources and minimize inspection and monitoring expenses.