Study On Mechanical Characteristics Of Buried Pipelines Under The Roadway

With the rapid development of economy and the advancement of the urbanization process, the buried pipeline is widely used in the current society. As an effective means of transportation of materials, buried pipelines are widely used in municipal, water conservancy, transportation, energy and other fields, plays an important role in modern industry and agriculture and people's life. With the following is, pipe types are increasingly diversified, pipe material is more and richer, and the load of the pipeline is also more complex. Buried pipelines that under the roadway, affected by the overlying soil load and traffic load, prone to deformation instability, rupture or leakage and other accidents. Once the accident has happened, inspection and maintenance is very difficult, would bring a big impact on the lives of the residents and cause waste of resources. In this paper, high density polyethylene pipe as the research object, on the basis of summarizing buried pipe mechanics analysis, traffic load simulation calculation, pipeline structure calculation and subgrade pavement engineering and other research situation, by means of theoretical analysis, example contrast verification and numerical simulation, analysis of soil pressure on the pipelines, cross section deformation of pipelines and the pipeline- soil interaction. Establish 2D and 3D finite element models respectively, study the mechanical properties and deformation characteristics of buried pipelines under the action of soil weight, static load and vehicle load. The research content and main conclusions are as follows:(1)Buried pipeline under the roadway including three parts of pipelines, soil and traffic loads, around these three parts, discusses the existing calculation theory of soil pressure on the pipelines, radial deformation of pipe section and additional ground vehicle load, combined with example to verify the existing classical calculation theory and compare with the finite element analysis results, and analyze the deficiency and error of the theoretical calculation.(2)Establish 2D finite element model to study the mechanical properties and deformation characteristics of cross section of buried pipeline, analyze the influence of buried depth, pipe diameter, relative modulus of pipe and soil, load position and size on the mechanical properties and deformation of pipeline. The vertical deformation and the maximum Mises stress of buried pipelines is proportional to the vertical earth pressure of the pipe, with the increase of buried depth, the overburden soil pressure is increased, the additional pressure of pavement is decreased, and there is a best buried depth in theory. Under the same circumstances of buried depth, small diameter pipes are more prone to damage, and rigid pipes are more easily damaged than the flexible pipe.(3)The road structure, buried pipeline and road traffic load are used as an organic whole; establish the 3D model of pipe-subgrade system, analyze the cross section deformation and internal force distribution of pipelines, study the mechanical characteristics of buried pipelines under different traffic loads, discusses the influence of pipeline buried depth, vehicle load type, load position and vehicle speed on the stress and deformation of the pipelines. The dangerous point of buried pipeline is related to the constraint condition of both ends of the pipeline; different kinds of traffic load, the mechanical response of the pipeline shows different characteristics; the speed and the wheel pressure have influence on the mechanical response and deformation of the pipeline.The methods and results of this paper can provide some theoretical basis for the design and construction of buried pipelines in practical engineering, and provide a reference for further research.