Geological disasters and pipeline defects are two major risks to safe operation of oil and gas pipelines. Mountain landslides are a common geological disaster in long-distance oil and gas pipelines. Cracks are one of the pipe defects that are difficult to be found but often occur in pipeline operation. When a pipeline pass-ing through the landslide area encounters pipe cracks， the effect of multiple loads may lead to the aggrava-tion of pipe cracks and even fracture failure. Based on the limit analysis design criterion， the influence of relevant factors on the axial crack of pipelines in the landslide area is studied. The influence of landslide width， landslide displacement， crack location， crack depth ratio， crack shape ratio and pipeline internal pres-sure on crack J integral is analyzed by the finite element method. Results showed： The greater the landslide width， the smaller the J integral， and the greater the land- slide displacement， the greater the J integral. When the crack is located at the 12 o’clock position， the J integral value is the largest， that is， the axial crack is the most dangerous when it is perpendicular to the landslide surface. The increase of crack depth ratio and pipe-line internal pressure will lead to an exponential increase in the maximum value of the J integral， while the increase of crack shape ratio will lead to a linear decrease in the maximum value of the J integral， and the maximum value of J inte- gral is obtained at the deepest part of the crack. A larger crack depth ratio will lead to crack propaga- tion velocity along the depth direction being much larger than that along the length direc-tion， and a larger crack shape ratio will lead to crack propagation velocity along the length direction being higher than that along the depth direction.
