Abstract: Based on model test results, the influence of model size on the mechanical and deformation properties of a buried pipeline under static load is studied by finite element numerical simulation software. The numerical results showed that when the distance between outside wall of the pipeline and horizontal boundary falls into the range of less than 25D(D, pipe diameter), the ultimate bearing capacity of soil gradually increases with the increase of the model size in horizontal direction.The variation regularity of pipeline radial deformation ratio in the process of loading is obviously different while the model size is different.Under the action of surface static load, the pipeline is mainly subjected to circumferential pressure. And due to the arch effect of soils at the top of the pipeline, the earth pressure around the pipeline reaches the highest at side of the pipeline, the second at top of the pipeline, and the smallest at bottom of the pipeline.Regularities for bearing capacity of the soils at top of the pipeline, for the force for the pipeline to take and for the deformation the pipeline maintain basically the same when the horizontal expansion of the outer wall of the model box exceeds 20D.

Key words: buried pipes, finite element method, boundary constraints, static load