A systematic literature review on permanent ground deformation patterns imposed on buried steel pipelines

Overtime, continuous research efforts have been devoted to investigating the effects of permanent ground deformation (PGD) on buried pipelines. These efforts have faced major uncertainties in the ground movement patterns that impose displacement-controlled loads on pipelines. This study presents a systematic review of the PGD patterns available in the literature for the analysis of buried pipelines, with particular emphasis on the PGD directions relative to pipeline axes. Depending on the directions, PGD patterns are divided into three groups: longitudinal, transverse and oblique. The relevant literature is organized into four main categories: experimental, numerical, analytical and probabilistic. Seven different PGD patterns (block, ramp, step, ridge, sinusoidal, asymmetric ridge, and asymmetric sinusoidal) available in the literature are discussed in this study. All these PGD patterns, except asymmetric sinusoidal, were applied in the longitudinal direction. In contrast, only three (block, sinusoidal and asymmetric sinusoidal) were applied transversely, which indicates a potential gap considering the randomness of PGD relative to pipeline axes. Besides, one additional PGD pattern (trapezoidal) is suggested in the present study based on the literature review. The findings of the present study show that 84 % of the reviewed cases considered either block or sinusoidal PGD pattern, while only 16 % considered the other PGD patterns (ramp, step, ridge, asymmetric ridge, and asymmetric sinusoidal). Almost all these 16 % reviewed cases assumed pipelines primarily as linear elastic materials. Based on these observations, the present study recommends a comprehensive study on the effects of all the mentioned PGD patterns on pipelines in all three directions.