Application study of stress sensing and control techniques for buried pipelines crossing landslide areas

Objective Buried pipelines that cross landslide areas are susceptible to deformation and damage due to the displacement load caused by slope sliding. Therefore, it is essential to study the levels and distribution patterns of stress in these pipelines and implement appropriate stress relief measures to ensure the operational safety of oil and gas pipelines.

Methods This paper presents practical research on post-landslide pipeline stress sensing and control, employing a vector finite element method in conjunction with ultrasonic stress detection and pipeline stress monitoring techniques. To address the deficiencies in stress evaluation and control techniques for buried pipelines that traverse landslide areas, the study focused on the pipeline section XTGD002, which crosses a landslide area on the Zhangshu-Xiangtan connecting line, part of the West-East Gas Pipeline II. Initial stress evaluations and dynamic stress monitoring were conducted on the pipeline subjected to slope displacement. Furthermore, pipeline stress relief was implemented using high-frequency monitoring data. The paper elaborates on the methods for initial stress evaluation, stress monitoring, excavation control, and safety margin analysis, all of which were validated through engineering operations carried out on-site.

Results Stress was concentrated at the center and in the shear zones on both sides of the slope, where the neutral plane of the pipeline was perpendicular to the orientation of the displacement load’s action on the slope. The study led to a method for optimizing the layout of monitoring points, based on the NDT results of circumferential welds in affected pipeline sections and their initial stress evaluation results. Additionally, it provided an economically rational stress monitoring solution for pipeline sections subjected to landslide impacts. Through field practices that address the technical processes involved in the excavation control of buried pipelines crossing landslide areas, a scientific and rational excavation control strategy was developed, emphasizing the staged cascade release of pipeline stress.

Conclusion The research outcomes demonstrate the applicability and feasibility of initial stress evaluation and stress monitoring techniques for buried pipelines crossing landslide areas, providing new insights into the evaluation and control of stress in these pipelines.