Mechanical response of X65 pipeline under rolling compaction of heavy trucks and the influencing factors

With the acceleration of urbanization, more crossings of roads and pipelines appear, which poses some threat to the safety of pipeline operation. Taking X65 pipeline as the research object, the mechanical response of pipelines under three types of dynamic loads, namely no-load, half-load and full load, was studied through field tests. A parameterized numerical calculation model considering the nonlinear pipe-soil interaction was established, and the accurate simulation of vehicle dynamic loads was realized, which indicates that the error between the numerical calculation results and the test results is within 5%. On this basis, the influence of vehicle weight, pipe diameter, wall thickness, internal pressure and other factors on the axial mechanical response of the pipelines was further investigated. The results show that the overall vertical bending deformation and local deformation are caused by the rolling compaction of heavy trucks. Meanwhile, the axial compressive stress applied to the top of pipelines and the axial tensile stress caused by the Poisson effect of internal pressure offset each other, so that the axial stress at the top of the pipeline decreases. However, the axial tensile stress at the bottom and side of the pipeline are superimposed with that generated by Poisson effect of internal pressure, which increases the axial stress applied to the bottom of pipeline. Therefore, increasing the diameter, wall thickness and buried depth of pipeline can reduce the influence of rolling compaction of heavy trucks on the pipeline. Besides, the weight of heavy trucks has the greatest influence on the axial stress of the pipeline, generally less than 100 MPa.