Definition - What does Bedding mean?
Bedding, in the context of trenchless technology, is the material laid below a pipe that supports the pipe against the top and adjacent soil load on the pipe. To prevent pipe failure, proper, graded bedding materials need to be compacted and laid all along the trench so that the load is evenly distributed. The greater the difference between the width of the trench and the pipe, the greater the load on the pipe.
Trenchlesspedia explains Bedding
The bedding material laid for the pipe depends on soil conditions at the site. The bedding needs to be prepared and compacted well because the load-carrying capacity of a pipe is highly dependent on the quality of support from the bedding below it. Improper bedding can result in deflection of flexible pipes like PVC in a vertical direction, creating breaks in the joints, causing leakages, or in the case of rigid pipes like concrete, causing the pipe to break at the point where the bedding does not support the overlying weight. There are different classes of pipe bedding - A to D - that are used depending on the strength of the pipe. Class B is the most favored bedding method.