What Does Axial Load Mean?
Axial load is the force acting on an object, parallel and on its axis. A buried pipeline may experience axial loads due to ground movement induced by slope instability. Some pipes made of flexible material may even experience changes in the cross-sectional area due to axial loading.
For calculating stress due to an axial load, the stress will be constant when cross-sectional area remains the same, but if the area changes, stress will also change.
Trenchlesspedia Explains Axial Load
Buried pipes can be damaged due to a variety of factors such as corrosion, external loading, construction defects, and ground movement. Ground deformation of a permanent nature as a result of seismic activities can lead to slope movement, lateral spreading, liquefaction, and landslides. To understand the effect of ground movement on buried pipelines, estimating the maximum soil resistance to axial loading is necessary.
The factors affecting soil resistance are pipe diameter, depth of pipe under the soil, and soil properties. The interaction between the pipe and the moving slope is a function of pipe orientation with respect to the slope. For a pipe axis normal to the direction of soil movement, the pipe will experience lateral force resulting in bending and shear stresses on the pipe wall. For a pipe that is parallel to the slope, stresses induced will be compressive or tensile due to the axial load on the pipe induced by soil movement.