Reliability analysis of city gas pipelines subjected to surface loads based on the Kriging model

Surface loads imposed on pipelines by illegal buildings in urban areas are common. A surface load can cause ground subsidence and pipeline deformation, as well as accidents such as leakages of oil and gas media and even explosions. In this paper, a pipeline reliability model based on stress–strength interference is established; based on structural reliability theory, the authors analyze the maximum equivalent stress of a pipeline’s dangerous section and pipe yield stress. Through the combination of the Kriging model and the method proposed by the Joint Committee of Structural Safety (JC method), the established limit state equation is approximated as a surrogate model, and the non-normal random variables are normalized using the JC method. The reliability indexes of the pipeline in the frame and brick–concrete structures were solved using MATLAB, and the results were verified and compared using the Monte Carlo Simulation (MCS) method. Through calculations, the reliability of the pipeline under the surface load of a frame-structure building was 0.9852, while the reliability of the pipeline under a brick-concrete structure was 0.9998, and the relative error with the MCS method was less than 1%. The method used in this paper has good applicability in analyzing the reliability of pressure-occupied pipeline and has certain reference and guiding significance for practical engineering.