Experimental study on the mechanical behavior of buried steel pipeline subjected to the local subsidence

Localized subsidence of soil layer is a typical geological disaster for buried long-distance oil and gas pipelines, which seriously threatens the safe operation of oil and gas pipelines. Therefore, a series of large-scale model tests are performed to investigate the mechanical response of the buried pipe induced by surrounding soil when the localized soil layer sinks. Results indicate that the subsidence height has a relatively greater impact on pipe strain and soil pressure than the subsidence range. Moreover, the distribution of the pipeline strain presents obvious regional characteristics and is divided into subsidence regions, non-subsidence affected regions, and non subsidence unaffected regions. With the increasing moisture content of the backfill, the strain of the pipeline and the earth pressure around the pipe was reduced. In addition, the modified Marston earth pressure formula is proposed to estimate the vertical earth pressure on the top of the pipeline. The vertical earth pressure calculated using the proposed method fits well with the test results.