Mesoscopic Study on Mechanical and Deformation Behaviors of Reinforced Buried Pipelines Under Vertical Loads

In order to deeply study the protective effect of geogrid-reinforced buried pipelines under vertical load, indoor model tests were carried out, and a discrete element simulation analysis model was established. The mechanical response and deformation behavior of geogrid-reinforced buried pipelines and surrounding soil systems under vertical load were explored from the mesoscopic level, and the development and evolution laws of the load-settlement curve of loading plate, contact force between particles inside the model, particle displacement, and vertical radial deformation of pipelines were revealed under different buried depths of pipelines and reinforcements. The results show that when the buried depth of the pipeline is shallow (H = 1.5D), the ultimate bearing capacity is smaller than that of the pipeline with a large buried depth. Although the settlement of the loading plate is smaller under the same load, the vertical radial deformation of the pipeline is large. After the geogrid above the pipeline is reinforced, the ultimate bearing capacity of the model system is significantly increased, and the vertical radial deformation of the pipeline is reduced. A shallower buried depth of the geogrid indicates a more obvious reinforcement effect. When the buried depth of the geogrid u is reduced from 0.75B to 0.25B, the ultimate bearing capacity is increased by about 57.2%, and the radial deformation of the pipeline is reduced by about 27.9%. In this study, the interaction mechanism among pipelines, soil, and geogrid is revealed from the mesoscopic level, and the mechanical and deformation behavior of geogrid-reinforced protected buried pipelines were visualized.