Analysis of the application of spiral steel pipes in the West-East Gas Transmission Project

The West-East Gas Pipeline Project has taken appropriate measures in spiral steel pipe anti-corrosion, pipeline design, construction, and dealing with complex environments to ensure pipeline safety.

During the design and construction of the West-East Gas Pipeline, we have always prioritized the safety of material selection for the pipeline. Based on the environmental conditions along the route and the reliability requirements of the pipeline, a combination of external anti-corrosion coatings and enhanced cathodic protection was used for pipeline corrosion protection. The external anti-corrosion layer of the pipeline adopts a three-layer PE coating, with a total of 42 cathodic protection stations installed.

Various assessments of geological hazards, including current evaluations, forecasts, and comprehensive analyses, have been completed. The danger levels were classified, and the main types and levels of geological hazards were determined. Land suitability was assessed, and countermeasures for geological disaster prevention were proposed. The activity of the major faults along the route was evaluated, and seismic calculations were performed for the pipeline crossing high-intensity areas. Seismic design was incorporated for eight active faults intersecting the pipeline in the initial design based on the seismic intensity of the region.

Additionally, different design coefficients were used according to relevant design specifications to ensure the safety of the pipeline and the environments it passes through. For particularly complex and challenging areas, the design safety factor of the pipeline was appropriately increased to ensure safety. The working width of the West-East Gas Pipeline construction zone is 28 meters in plains and 18 meters in mountainous areas. The trench cross-section is typically trapezoidal, with the width of the upper opening not exceeding 5 meters and the depth generally not exceeding 2.5 meters.

To ensure the safety of the pipeline in areas such as large rivers and mountains, methods like crossings, tunnel passes, and pipe jacking were adopted. For different regions along the route, suitable protective measures were taken, such as focusing on stabilizing sand in the desert regions of Xinjiang and Gansu, while prioritizing pipeline stability in the plains of Henan-Anhui and the water network areas in southern China.

During the construction of the West-East Gas Pipeline, special attention was paid to environmental protection along the route. The project’s ecological environment along the route is complex and variable. We initiated the "Long-Distance Pipeline Ecological Environment Safety, Restoration, and Component Research" project, systematically analyzing the relationship between pipeline construction and the ecological environment along the route. Environmental protection and restoration requirements were proposed, and specific ecological protection and restoration technical plans were developed.

During pipeline construction, a comprehensive QHSE (Quality, Health, Safety, and Environment) management system was established and improved to ensure the harmonious integration of pipeline construction with quality, health, safety, and environmental protection. Efforts were made to reduce the damage to the natural environment during construction, prevent environmental pollution accidents, and ensure that pollutants were discharged only after meeting relevant national standards.

For example, in the protection of the Zhongshan Grotto cultural heritage site in Shaanxi Province, efforts were made to minimize blasting and excavation in the pipeline route, controlling the amount of explosives used and conducting necessary trial blasts. In special cases, manual trenching was used to meet cultural heritage protection requirements. When the pipeline passed through the densely vegetated forest area of Dajianshan, tunnels were used as much as possible, and additional investment was made in some areas to avoid damaging trees. For specific locations along the pipeline, such as the loess ridges, targeted special designs were implemented, using gray soil backfill to widen ridges, and building interception and drainage ditches as soil and water conservation measures. In both design and construction, the focused disposal and protection of waste generated from tunnel construction were considered. Appropriate engineering measures such as drainage, backfilling, sealing, deep burial, and water-blocking walls were implemented to ensure pipeline safety and reduce soil erosion.

These seemingly small actions laid a solid foundation for environmental protection and created conditions for pipeline safety.