Method for identifying the main factors controlling landslides based on a particle coupling algorithm simulating the ultimate state of a gas pipeline

Abstract

To determine the ultimate load of buried gas pipelines under different working conditions under landslide action and provide a quick decision-making tool for landslide risk management, a pipe–soil coupling model is established based on smoothed particle hydrodynamics and the finite element method. The double elastic slope criterion and fault tree analysis method are used to perform limit and failure analyses on the pipelines. The research results indicate that pipeline stress and strain during oblique crossing are positively correlated with the crossing angle. The upper section of the pipeline exhibits tensile bending, whereas the lower section exhibits compressive bending. Local stress is concentrated at the elbows at both ends of the pipeline during longitudinal crossing, which is similar to the force applied during oblique crossing. The ultimate pipeline bearing capacity is negatively correlated with its burial depth and pressure. There is a positive correlation between the distance from the pipeline to the rear edge of the landslide and the width of the landslide. There is also an optimal value for the moisture content of landslides. Fault tree analysis reveals that, to prevent pipeline failure under the action of landslides, priority should be given to determining a reasonable pipeline laying method, reducing the moisture content of the sliding body, controlling the thickness and width of the landslide body, controlling the displacement and inclination angle of the sliding body, timely eliminating soil and soil pressure, and avoiding the failure of drainage systems and support facilities. Based on the research results, we propose a method that can preliminarily identify the main control factors affecting pipeline integrity. This method provides a reference for studying and developing engineering mitigation measures, identification procedures, and operation guidance documents for geological disaster risks for pipelines crossing landslide sections.