Study on Disaster Mechanism of Oil and Gas Pipeline Oblique Crossing Landslide

Abstract

Landslides are one of the most serious geological disasters in oil and gas pipelines. According to investigations, the cross-cutting relationship between landslides and pipelines can be divided into three types: pipeline longitudinal crossing landslide, pipeline transversely crossing landslide, and pipeline oblique crossing landslide. This different cross-cutting relationship is one of the important factors affecting pipeline landslide disasters. As a result, it is necessary to study the stress and deformation characteristics of oil and gas pipelines under different cross-cutting relationships, which is of great significance for the prevention and control of oil and gas pipeline landslides. In this paper, an ideal pipe-soil coupling interaction model of oil and gas pipeline oblique crossing landslide was established using FLAC3D. The influence of the buried depth of the pipeline, the displacement of the sliding body, and the different intersection angles of landslide and pipeline on the deformation and stress of the pipeline under the action of a landslide is analyzed, and a typical case of pipeline oblique crossing landslide is used for analysis. The results demonstrated that the stress of pipeline oblique crossing landslide is complex, and the stress concentration is obvious at the shear outlet and the trailing edge of the landslide. The stress at the shear outlet is the largest, which should be regarded as the key location. The displacement and stress of pipeline oblique crossing landslide are obviously affected by the displacement of the sliding body and the buried depth of the pipeline. The displacement and stress of the pipeline increase significantly with the increase of the displacement of the sliding body. With the increase of pipeline buried depth, the displacement of the pipeline shows an overall decrease, and when the buried depth of the pipeline is 3–3.5 m, the displacement and stress are close to the peak, indicating that the buried depth is of great risk. The intersection angle between the pipeline and landslide has a significant effect on the stress of the pipeline. The smaller the intersection angle, the safer the pipeline is.