Mechanical response of polygonal-shape transverse buried gas pipeline under the action of landslide

The gas pipeline of Zhongwei-Guiyang tie line K1224 at the slope is a typical polygonal-shape transverse buried pipeline. Due to rainfall and road excavation at the toe of the slope, the slide of this slope leads to pipeline deformation. In this paper, based on numerical modeling and in-situ monitoring, the destruction characteristics of landslide deformation under different operating conditions and the corresponding mechanical response of the pipeline were analyzed by means of the incomplete coupling of pipe-soil separation. It is indicated that the activity of the landslide is intensified by road excavation at the toe of the slope together with rainfall. The horizontal displacement of the pipeline along the sliding direction of the slope is particularly obvious, and the phenomena of sudden displacement increase occured near the turning points of the pipeline. The stress near the turning points of the pipeline is much higher than that in straight sections. Due to the uneven landslide displacement controlled by microtopography and its moment, the stress concentration degree near the turning point in the southern side of the pipeline is the highest. What's more, the stress near the turning point in the southern side of the pipeline is close to the stress limit of the pipe material, so this part is the most dangerous area of this pipeline section.