Landslide is the main geological disaster that threatens the safe operation of natural gas pipelines. It is of great significance to investigate the analysis method that is suitable for the evolution law of landslide and the mechanical response of overburden pipes in engineering. Therefore

based on the principle of the minimum potential energy

the total potential energy balance equation of slope system (from anti-sliding section to sliding section)

i.e.

the Lagrange variational equation

was firstly adopted to obtain the critical conditions for the instability and slip of the slope. When the strain energy of the sliding section is equal to the strain energy for the crack and penetration of the anti-sliding section

the slope will slip. Meanwhile

the strain energy stored in the slope will be transformed into kinetic energy. On one hand

according to the contact relationship between the rock mass and the pipeline during the sliding process

the mechanical response model of the pipeline in two landslide stages is proposed. On the other hand

considering the fragmentation of the rock and soil mass

the uniform stress model of pipeline under the action of rock landslide and the non-uniform stress model of soil slope pipeline are proposed respectively. In view of this

based on the mechanical response for the small-scale interaction of the pipeline and soil

the stress expression of the pipeline in the pre- and post-sliding stages of rock and soil slopes

which is suitable in the elastic part

is derived. Finally

taking the EES244 section of natural gas pipeline from Sichuan to East as the research target

the total potential energy equation of the slope system is established

the situations for deformation

instability and slip of the slope are analyzed

the stress values of the pipeline in different sliding stages are calculated

and the safety of the pipeline is evaluated. Meanwhile

the stress analysis and the safety verification of the pipeline are carried out from a large-scale perspective by means of the numerical method. The results show that a sudden change of stress in the pipeline will be occurred near the interface between the sliding zone and the non-sliding zone

and the internal stress in the sliding zone increases slightly

while the whole pipeline is in a safe and stable state. Therefore

combining the small-scale theoretical calculation and the large-scale numerical method is of great significance and practical value

especially for the preliminary designing of the proposed pipeline

the safety evaluation of the existing pipeline and the later maintenance of the pipeline.