What Does Overburden Pressure Mean?
Overburden pressure (also known as overburden stress or vertical stress) is the pressure exerted by layers of soil above a buried pipeline. Trenchless pipeline construction methods such as pipe jacking and microtunneling are carried out below the earth's surface at pre-determined depths.
For designing buried pipelines it is necessary to know the overburden pressure that the pipeline will have to bear so that the pipe does not fail under stress.
In places where the pipeline will pass under highways and railroads, the live load that will pass over the section is also considered.
Trenchlesspedia Explains Overburden Pressure
Buried pipes inevitably experience overburden pressure from the weight of the soil above it. When live loads are also present, the pipe will experience hoop stress and longitudinal stress. The total pressure on the top of the pipe will be the sum of the components of the live load and overburden pressure.
The longitudinal stress on the pipe from the surface loading is due two factors; (a) local bending in the pipe wall which is approximately the Poissons ratio of the pipe material multiplied by the hoop stress due to local bending, and (b) due to the bending of the pipe axis under the non-uniform distribution of pressure on the pipe top in the direction of the pipe axis.