Reliability analysis method for buried pipelines based on probability density evolution

Conducting the dynamic analysis of buried pipelines subjected to seismic action poses a complex engineering challenge. A reliability analysis method based on probability density evolution and the equivalent extreme value distribution was developed in full consideration of the randomness inherent in ground motions. This method offers a probabilistic and statistical perspective for investigating the stochastic dynamic response and reliability of buried pipelines. The method was used to conduct the stochastic dynamic analysis and reliability assessment of pipeline displacement, and its validity was compared and confirmed against the Monte Carlo Simulation (MCS) method. The results demonstrate that the Generalized Probability Density Evolution Method (GPDEM) is an economical and efficient approach for use in seismic dynamic reliability analysis, with broad applicability in the dynamic reliability analysis of nonlinear structures under seismic actions. The displacements of buried pipelines are highly sensitive to seismic action, undergoing significant nonlinear changes, and pronounced horizontal reciprocating motions can exacerbate fatigue damage in pipelines. Furthermore, pipelines may gradually subside over time, posing a severe threat to their safe operation. To ensure the seismic safety of buried pipelines, it is crucial to assess their seismic performance by considering the randomness of ground motions. A single evaluation index is inadequate for accurately assessing the performance level of buried pipelines across all time states. Results show that a reliability analysis based on the GPDEM can reasonably characterize the evolution of the probability density function of the dynamic response of buried pipelines during seismic events, thereby providing a theoretical foundation for the seismic design of buried pipelines.