INVESTIGATION OF INFLUENCE OF TECHNOLOGICAL PARAMETERS ON THE PIPELINE BUCKLING ON THE EXAMPLE OF GAS PIPELINE 'BLUE STREAM' THEORY, CALCULATION, EXPERIMENT

摘要

The article contains the statement and solution of the problem of pipe buckling under external pressure and bending taking into account deviations of circular cross section, non-elastic deformation and actual "stress-strain" diagram. It is shown that during deep water pipelaying there is an additional reserve of bending capacity. The situation of only external pressure is investigated more carefully. It is demonstrated that modification of "stress-strain" diagram due to Baushinger phenomena after cold expansion significantly and negatively influences on pipe buckling capacity. Calculation results are in good compliance with unique full-scale experiment performed for "Blue Stream " project. The article contains the comparison of calculations for different diagrams as per formulas recommended by DNV Rules for submarine pipelines and INTEC Engineering. Calculations based on actual compression diagram after cold expansion are in good compliance with INTEC method for low actual ovality DNV Rules application for calculations of expanded pipes gives systemic non-conservative error. Deviations are explained not by yield strength value but by actual diagram type. The article includes a list of investigations necessary for update of deep water pipeline stability in case of new materials usage and anisotropy.