Local Buckling Strain Failure Criterion of Large Diameter Gas Pipelines

Abstract Large bending and axial compression are two typical load conditions that cause axial buckling in buried oil and gas pipelines. A numerical simulation model is established using nonlinear finite element software to compare the buckling response characteristics of pipelines under these two types of loads and to explore the applicability of the current standards “Oil and Gas Pipeline Systems” (CSA Z662-2011) and “Seismic Technical Code for Oil and Gas Transmission Pipeline Engineering” (GB/T 50470-2017). The influence of different parameters on buckling is analyzed. By comparing the ultimate compressive strains obtained from simulations under various conditions with the ultimate compressive strains calculated using the recommended formulas in CSA Z662-2011 and GB/T 50470-2017, it is found that the results from CSA Z662-2011 and GB/T 50470-2017 are not conservative for the axial compression model but are conservative for the bending loading mode. The ultimate compressive strain of the pipeline under axial compression load is always smaller than that under bending load. Based on the simulation results, an analytical formula for calculating the ultimate compressive strain of the pipeline with higher accuracy is obtained. The research results can provide guidance for pipeline engineering design and construction.