Dynamic stability analysis of pipeline based on reliability using surrogate model

摘要

The surrogate model is applied to a reliability analysis of the stability of untrenched pipelines. Experience has shown that the stability of a pipeline is sensitive to a number of variables associated with soil properties, structural modelling, and hydrodynamic loads. Because uncertainties are unavoidable in these key design parameters, it is vital to evaluate pipeline instability failure using a probabilistic approach. However, a reliability analysis of on-bottom stability in the time domain is often a very computationally expensive process.The stability of a pipeline exposed to time-varying environmental loads is a highly nonlinear phenomenon with pipe-soil-fluid interactions. In this work, surrogate model technology was utilised to realise the reliability analysis which is also quite time consuming. A Fourier model was used to calculate the hydro-dynamic forces acting on a pipeline.The surrogate model was constructed using experiment sampling and, in conjunction with a Monte Carlo simulation, was employed to perform the reliability evaluation. Moreover, the influences of various random variables on pipeline instability are discussed through a sensitivity analysis. An accurate assessment of the conservatism in the different variables could lead to fewer conservative stabilisation requirements.The results show that using a surrogate model for reliability analysis not only reduces the computational cost significantly but also produces a highly accurate evaluation of pipeline stability.