Research on mechanical response of buried steel pipelines under continuous collapse

Formation collapse is one of the common geological hazards for the buried long-distance pipelines. In order to study the mechanical response law of the buried steel pipelines under continuous collapse, experiments and numerical simulations of buried steel pipelines under continuous collapse were carried out, the deformation and stress changes of the buried steel pipelines during continuous collapse were analyzed, and the theoretical calculation results of pipeline mechanics under the collapse geological hazards were checked. The research results show that, in the case of collapse in a small area, the deformation and stress of pipelines increase continuously with the collapse area enlarged, and the displacement and stress in the middle of the pipelines are maximized. When the collapse area is expanded to a certain extent, the soil collapses completely, the pipelines are suspended, the displacement of the pipeline is reduced, the stress of the pipe is released greatly, and the maximum stress position of the pipelines changes from the middle to the point near the collapse boundary of the pipelines. The calculation results of the pipeline stress under the collapse geological hazards are greater than the experimental and simulation values if the friction or cohesion are considered based on the gravity, which are of more guiding significance. Further, the reasearch results could provide effective guidance to pipeline protection.